This is an significantly expanded and revised version of a zeppelin timeline I posted several years back over several separate posts. Since it has been a while and rigid airships are always a staple of AH, I thought I'd do this again. As it was originally, it is styled as a history book or journal article written from the timeline. I'm also doing a desktop published version with CanisD illustrations (with permission), photos (some real many faked or misrepresented), and tables.
The timeline depends on several PoDs, mainly USS Akron and Macon not being lost in the 1930's and the enactment of the 1928 "Airship Act" that would have give airship airlines favored status a the flag us carrier (this almost happened).
The Early Years
In view of the tremendous value of the Navy’s rigid airships during the 1941-45 Battle of the Atlantic, it is instructive to realize that, during several periods in the 1920’s and 1930’s, the entire program came very close to being eliminated. For at least the first fifteen years of their service in the US Navy, rigid airships were considered by all but a few advocates as unnecessary and ineffective experiments forced upon the fleet by a few important senior commanders and influential members of Congress representing districts which stood to benefit by the development of an airship industry in the United States.
From the beginning, both traditional “battleship admirals” and the new naval “airpower advocates” had little use for the zeppelin airship. In an environment of limited funding, traditionalists considered airships unproven competitors with light cruisers, submarines, and other vessels with clear offensive capabilities in naval warfare. Air power advocates, on the other hand, saw airships as directly competing for scarce aviation funds with flying boats and aircraft carriers. Since the only military mission the zeppelin was believed suitable for was unarmed scouting and reconnaissance, and even this had not been proven, most navy officials were unhappy to sacrifice either surface ships or airplanes to build rigid airships .
In fact, early US experience with rigid airships tended to support this pessimism. Both ZR-1, USS Shenandoah, and ZR-2, the unnamed British R-38, were destroyed in crashes before either ship had a chance to demonstrate any military value. Their loss reinforced the impression among the US public and many naval personnel that zeppelin airships were fragile craft, excessively vulnerable to weather conditions and inherently unsound. Lost in these accusations was the fact that neither ZR-1 (a copy of a 1916-vintage German naval zeppelin), nor ZR-2 (based on the very lightly-built German “height-climbers, and widely believed to be a particularly faulty design) were designed for North American weather conditions or rigorous low-altitude fleet scouting operations.
Even the highly successful ZR-3, USS Los Angeles, did very little to advance the cause of the rigid airship in the US Navy. Because ZR-3 was a new airship built by the Zeppelin Company as war reparations (to replace German naval zeppelins destroyed by their crews after the armistice), Britain and France insisted that the ship be built as a non-military vessel and not operated as a part of the fleet . Thus, while the ship served well to train crews and “show the flag” across the country for over 10 years, it had little opportunity to demonstrate any value to key decision makers in the Navy Department.
A Change in Fortunes
The Goodyear-Zeppelin Corporation was founded in 1923, as a joint venture of Goodyear Tire and Rubber Corporation, of Akron, Ohio, and the Zeppelin Company in Germany. This provided US airship designers with full access to all Zeppelin patents and trained design staff. Following in the early 1930’s, Goodyear-Zeppelin as well as the German Zeppelin Company proposed a number of subsidiary commercial airlines to operate trans-Atlantic and trans-Pacific passenger and mail service in Goodyear-Zeppelin built airships.
In 1928, following strong lobbying efforts from the Goodyear-Zeppelin Corporation, and as recommended by the United States Maritime Commission (USMC) and National Advisory Committee on Aeronautics (NACA), the United States Congress passed “An Act for the Establishment of a Commercial Airship Transportation Industry in the United States”, commonly referred to as “the Airship Act” . While this act initially provided no direct funding for the construction of airships or related industries, it set US policy to establish Goodyear-Zeppelin’s airship airlines as the official US flag carriers in any future trans-Atlantic or trans-Pacific airborne commerce, provided for all commercial airships to be constructed to US Navy specifications and be crewed by naval reservists, and require all civil airships and facilities liable for nationalization as naval auxiliaries in the event of war or national emergency.
In 1934, as an important element of the New Deal public works recovery measures implemented by Franklin Roosevelt, the Airship Act was amended to provide funding for several large airship-related construction projects. This included three new airship building sheds at the original Goodyear-Zeppelin Air Dock in Ohio; and four combined building sheds/hangars to be wholly operated by the Navy, two each at existing naval air stations (Sunnyvale, California; and Lakehurst, New Jersey).
In subsequent years, the Act was amended further to provide additional Works Progress Association (WPA) funding to build up to eight “civilian” airships similar in basic design to the Navy’s ZRS-4 (USS Akron) type airship, with passenger spaces occupying areas used as airplane hangers in the naval ships. WPA funds were also used to build other infrastructure supporting the commercial airship industry, including helium extraction plants, duralumin fabrication factories, hangers, and passenger/freight handling facilities. Also under the amended Airship Act, NACA established the Merchant Airship Academy in San Francisco, California, to provide training to civil (and potential naval) aircrew and air dock workers.
A vision of the future – the ZRS class ships
Despite positive developments in the civil arena, the role of the rigid airship in the US Navy remained uncertain through the early 1930’s. Goodyear-Zeppelin’s first rigid airship, ZRS-4, USS Akron, entered service in early 1931. A key improvement in this ship and its immediate successors was the provision of an internal hangar capable of handling and servicing five small Curtiss F9C fighter planes. In early training exercises, Akron was operated very conservatively and made little use of its airplanes. Employing tactics more suited to the German Navy in 1916, Akron’s commanders tended to use the airship itself as the scout, only launching planes after contact was made. As they soon discovered, attempting to locate and stealthily track surface ships in a gigantic silver object flying at only several thousand feet was virtually impossible. In fleet exercises, Akron was often seen and “shot down” by surface ships or ship launched floatplanes before she herself saw the ships. As her crew became more experienced with their ship, Akron began to use her airplanes more as primary scouts, but in two years flying, the ship had not demonstrated any real value to the fleet.
Akron’s sister ship, ZRS-5, USS Macon, entered service in 1933, and at that point things began to improve. Prior to this, all failings of the Akron in fleet exercises were automatically interpreted as a basic failing of the airship as a type, not as a possible product of poor crew performance or sheer bad luck. With two ships at its disposal, the Navy could now compare the performance of these ships and better understand how and why they performed as they did. Also, as would be expected, there was a natural evolution in the effectiveness of their commanders and crews as they learned from each other and became more experienced with the unique abilities and drawbacks of these giant ships.
The navy’s rigid airship program narrowly escaped a major setback in early 1935 when USS Macon suffered a serious casualty to her upper fin during a routine training exercise off Point Sur, California. A sudden gust of wind tore most of the upper fin off the ship, resulting in secondary hull damage and almost total helium loss in gas cells I and II. Only the extremely prompt and efficient action of her officers and men kept the ship aloft, and she was able to return to Sunnyvale with only minor additional damage. Not only did this accident help show that large rigid airships might be less susceptible to loss through battle damage than previously thought, it uncovered a potentially serious design flaw in the Akron/Macon fin design that could be adequately (if not ideally) corrected by strengthening of the forward fin attachment points, which unlike all previous and subsequent airships, were not cruciform structures.
Macon was repaired and back in service in July, and by late 1935, most senior officers accepted Akron and Macon as useful, if not exceptionally valuable, adjuncts of the fleet. The ships’ commanders had developed effective operational doctrine focusing on the use of the ships’ F9C fighters to greatly extend the effectiveness of the airships as strategic scouts, and their crews were both well trained and experienced. In the six “Deep Pacific” fleet problems undertaken in late 1935, the airships proved themselves very effective long range scouts, frequently locating and identifying “enemy” forces well in advance of other scouting vessels or carrier-launched scout planes. Although they often found themselves “shot down” as the problems evolved and the operational areas became more congested, this usually occurred well after they had provided information judged sufficiently important to justify their loss. Nonetheless, there was very little interest in investing additional funds for such large and expensive units which lacked any offensive capability of their own. It appeared Akron and Macon would remain the only fleet airships in the US Navy for the foreseeable future.
The Turning Point
A key event transforming the Navy’s grudging acceptance of airships to advocacy was Fleet Problem XIII in February, 1936. This featured a simulated “Orange” attack on a “Blue” base in the Panama Canal Zone. Orange, presumed to have occupied Pearl Harbor, was tasked with mounting successful airstrikes and shore bombardment of the Panama Canal Zone in preparation to a hypothetical invasion. Since the exercise presumed Orange had seized the initiative in the war, it was provided a powerful strike force centered on both main fleet carriers (USS Lexington and USS Saratoga) supported by the battleships USS Colorado, USS West Virginia, USS Tennessee, and USS New Mexico, and a mixed screening force of light cruisers, destroyers, and submarines. Blue was deliberately provided a much smaller defensive force comprising only two older battleships (USS Wyoming and USS Arkansas), the small carrier USS Ranger, two heavy cruisers, a few submarines, shore-based flying boats, coastal aviation, and the Akron and Macon. Although the problem was designed primarily to explore doctrine regarding the offensive use of aircraft carriers, it was also an ideal situation for the two rigid airships to demonstrate their unique and unmatched capabilities as high speed, high endurance, long range aerial scouts. This, along with a combination of ideal weather conditions for airship scouting and poor decisions by Orange fleet commanders, ensured their outstanding success.
Operating together under the overall command of Admiral William Moffett, and assisted by an unusually strong northwesterly tailwind, Akron and Macon moved at extremely high speed toward the Orange fleet’s projected approach route. This placed them in the general vicinity of the Orange fleet well before they would normally be expected to arrive. Very early in the exercise, Macon’s scout planes were able to locate the advance scouting screen for the Orange force in the open Pacific over 1500 miles from the Canal Zone and report the location and heading to the Blue main force.
Making excellent use of their scout planes and employing the low cloud cover to maximum effect, the airships were able to swing round the advancing enemy and take up station behind the main Orange force of battleships and carriers, just outside of visual range. Although Moffett expected his airships would eventually be located and “destroyed” by Orange’s carrier planes, they remained undetected throughout most of the problem, providing valuable coded information from their F9C scout planes to Blue’s main force.
On the other hand Orange, under the overall command of Admiral William Halsey, made far less effective use of its scouting assets. Although radio signals from the airships eventually gave Halsey a general idea of their relative bearing, he inexplicably made no serious effort to find and “destroy” them, claiming in his debriefing that he was worried his own scout plains might actually collide with them in the low clouds. In other respects as well, Orange aerial reconnaissance was unexpectedly poor.
Presuming inaccurately that the weak Blue fleet would seek to engage near the Canal Zone under the protection of its land-based aircraft and shore batteries, Orange continued to push ahead toward Panama at high speed. In fact, Blue Force commander Admiral Ernest King adopted the opposite strategy. Knowing that Halsey ultimately needed to enter Panamanian waters with effective air cover to offset Blue’s substantial land based air assets, King hoped to attack and eliminate one or both of Orange’s carriers early in the exercise. This would deprive Halsey of the air support he needed for a successful strike.
Toward the end of the second day of the problem, information provided by the airships allowed the Blue submarine USS Cuttlefish to infiltrate the Orange screen and “torpedo” USS Lexington, the referee on board the aircraft carrier ruling her “severely damaged” and requiring her to return to Hawaii. Halsey complied and detailed two destroyers to escort her.
Guided by information from Akron and Macon, King was able to avoid the Orange scout screen. Thus, by 0400 on the 3rd day of the exercise, the main Blue force consisting of the carrier USS Ranger and the heavy surface units had reached a position less than 150 miles northeast of the Orange main force.
At 0700, the Ranger launched its small strike force, which achieved complete surprise. Referees judged the Saratoga’s flight deck irreparably damaged, making her unable to operate aircraft for the remainder of the problem. They also ruled all of Ranger’s attacking aircraft lost in the action, but by then the damage was done. In two separate actions made possible by reconnaissance from Akron and Macon, Orange had lost all of its offensive and defensive air support. Halsey recognized that, in a real combat situation, any attempt to proceed with close-in shore bombardment without air cover could be disastrous. He then sought instead to bring the Blue force containing the Ranger into a surface action against his overwhelming force of battleships. Unfortunately, he was unable to locate the Blue ships, and they succeeded in slipping away.
By then, the two Blue airships had divided up, Akron continuing to shadow the main Blue force, with Macon tailing the “crippled” Lexington en route to Hawaii. Since the aircraft carrier had been ruled to be “heavily listing“ after the Cuttlefish’s “torpedo hits” it was not permitted to operate its aircraft, making it essentially a blind sitting duck. Knowing this, Admiral Moffett on the Macon prevailed on the referees to presume that, in an actual wartime situation, he would have a small number of 250lb bombs on board which could be changed out for the F9Cs’ external fuel tanks.
As required by the referees, Macon’s HTA unit simulated the “bombing up” of their aircraft by removing and then replacing the fuel tanks on three fighters currently in the hangar being refueled, and less than 2 hours after Moffett received approval from the judges, they were launched. The three planes soon arrived over the “crippled” carrier and made a perfect low angle bombing run across the length of the flight deck. To add insult to injury, the F9C pilots dropped toilet paper rolls as they flew by, all of them bouncing off the ship’s deck. Faced with such evidence, the referee on Lexington ruled the attack successful. Because the bombs were small, the Lexington was not “sunk”. However, the referee did rule that the attack started fires resulting in the loss of parked aircraft and personnel. In exchange, the three F9Cs were ruled “shot down” by Lexington’s anti-aircraft batteries and escorting destroyers. However, Macon’s attack showed that, in the right situations, aircraft carrying rigid airships could be effective offensive weapons.
As a result of Fleet Problem XIII, the rigid airship went from being a tolerated curiosity to a potentially valuable naval asset. All of the plans and designs which had been languishing for years at the Navy’s Bureau of Aeronautics (BuAer) Lighter-than-Air section now had a real chance of seeing fruition.
The Prewar Buildup, 1936-1941
The Navy requested and received authorization to procure two more ZRS type ships in the 1936 naval appropriations. The first ship was already well under construction at the Goodyear-Zeppelin Air Dock as the third commercial ship authorized under the amended Airship Act. She was based broadly on the Akron design, but her hangar bay was replaced by internal accommodations for 50 passengers, crew, freight, and mail. Following a redesign to restore the airplane hangar and bring all other elements of her design to operational naval standards, she entered service as ZRS-6, USS Wichita, in early 1937.
ZRS-7, USS Newark, was designed and built from the keel up as a naval airship and entered service in early 1938. Newark was built to a significantly revised experimental design proposed by the Navy’s Bureau of Aeronautics (BuAer). This corrected the design flaws which almost led to Macon’s loss in 1935 and, more significantly, replaced the internal airplane hangar and trapeze of Akron, Macon, and Wichita with a strengthened keel mounting six individual airplane launching stations and trapezes in tandem along the bottom of the ship. Although the planes’ partially exposed stowage restricted the ability of the HTA unit to perform extensive maintenance on them, the individual launching stations promised much quicker launching and retrieval operations. This system soon proved itself very efficient and, after USS Newark, no further naval airships were built with internal hangars.
In 1940, the Navy also received one additional airship from a very unexpected source: Nazi Germany.
When the European War broke out on September 1, 1939, the German airliner LZ-130 Graf Zeppelin had just completed its final westbound crossing of the North Atlantic season and was being serviced at the Lakehurst Air Dock. Because the Graf’s return voyage to Germany would of necessity take it over French or British airspace, and neither Allied nation would guarantee its safety, the ship was interned by the United States.
The Graf reigned as a hangar queen until April, 1940, when the United States Navy offered to purchase the ship from the Deutsche Zeppelin-Reederei. Initially, this offer was made, not so much to procure another airship for the Navy, but to restore full hangar capacity at Lakehurst for the new ZRCV airships under contract. After some negotiation, including a stipulation that the ship would not be based in the Atlantic or transferred to any Allied nation, the Nazi government approved the sale, believing that this highly visible and successful diplomatic deal with neutral America outweighed any potential risk that the ship might be of military value to the US Navy in the event of a war with Germany.
Although some thought was given to simply scrapping the ex-German ship, BuAer successfully argued for its refitting and incorporation into the fleet. At the time of its purchase, the state-of-the-art Graf was one of the largest operational airships in the world, capable of carrying a sizeable number of aircraft if properly refitted. In June the now-unnamed airship was flown to Goodyear-Zeppelin’s Airdock at Akron for conversion. Her passenger accommodation bay was reconstructed to house an airplane hangar with associated service and crew spaces, and several supplemental trapeze stations were added along the lower keel.
As requested by Germany, she was assigned to the Sunnyvale Naval Airship Training Squadron in California as ZRN-3. She received the name USS Bismarck. This odd name for a US ship in 1940 was ostensibly in honor of the capital of North Dakota, but there is anecdotal evidence it was indeed a deliberate double entendre to reflect the ship’s German origins.
Following the German declaration of War in December 1941, the airship was put into active service and assigned to Rigid Airship Patrol Squadron 3 at Lakehurst. Because her airplane hangar limited the size and capability of the aircraft she could operate she was rerated as a scout airship and designated ZRS-8. She was also renamed USS Belleau Wood, which also had German connotations, but of a nature far more suitable to a warship of the US Navy engaged in combat with Germany.
The ZRCV Ships – Aerial Aircraft Carriers
Before the ZRS-7 design was finalized, BuAer requested a series of design studies for the next generation of rigid airships for the navy. Unlike the previous ZRS ships which were not optimized to carry the larger and heavier naval aircraft coming into service, the ZRCVs were designed from the keel up as dedicated aerial aircraft carriers that would be able to operate a wide variety of modern aircraft. In their ultimate design, these became the largest operational airships ever built, being over 900 feet long and containing a volume of over 10,000,000 cubic feet of helium gas. The ships carried trapezes and launching/retrieval stations for up to 10 hook-on aircraft.
The initial 1936 design study offered by Goodyear-Zeppelin, ZRCV-A, was proffered prior to BuAer’s disenchantment with internal hangars and was little more than an enlarged version of Akron, retaining the deep ring construction, the lateral keels with internal engines, and an internal aircraft hangar. With a volume of 8,500,000 cubic feet, ZRCV-A could have carried as many as 8 aircraft similar in size to the F2C in a hanger one-third larger than that fitted on the earlier ship.
However, continued experience with the Akron-class ships had pointed out difficulties with their aircraft handling systems. The principal complaints expressed by airship officers involved the inefficient and complex monorail system that moved the F2C’s around in the hanger and the fact that only one airplane could be readied and trapeezed down for launching at a time. Even after aircraft operations from the Akron-class ships were perfected, it often took as long 20 minutes to ready and launch each plane, meaning that by the time the last airplane was out, the first could be nearing the end of its flight endurance.
Because recovery and stowage of each airplane was also a time-consuming matter, operation of all five aircraft at the same time was virtually impossible except over land or in the vicinity of an aircraft carrier where planes running short on fuel could land if necessary. Since this would be highly unlikely when the airships were operating in their intended role as long-range naval scouts, Akron and Macon rarely had more than two of its airplanes flying at the same time in their pre-war training flights. To improve this situation, airship commanders began to fit each ship with a series of “perches” on which pilots could hook, but this was an awkward and unsatisfactory solution.
Finally, in rejecting the ZRCV-A design, BuAer noted that the F2C was selected for service from the Akron-class ships solely because it was the smallest relatively high-performance airplane available that could fit through the hangar doors, not because it had any other particularly desirable traits. By the early 1940’s the F2C would be thoroughly obsolete for any useful purpose. Further, BuAer believed that any new purpose-built airplanes capable of being stowed in an internal airship hanger would be limited in size by the hangar and its door. Such airplanes would also be outclassed by their larger land- or carrier-based equivalents in a few years. Since the future ZRCVs were intended to operate with the fleet as dedicated aircraft carriers with an effective offensive capability, a way had to be found to both improve the efficiency of aircraft operations and provide for continual upgrades to larger and heavier airplanes capable of delivering effective ordinance loads.
Goodyear-Zeppelin had anticipated this problem and proposed design study ZRCV-B. This was very different from the Akron design. It reverted to “traditional” zeppelin practice with external engine cars and a strong ventral keel, widened aft of the control car to provide a long internal hangar, from which 8 airplanes could be hung in tandem on their own trapezes. As a concession to crew safety and comfort, however, retractable doors were provided beneath each aircraft to provide an enclosed service area
BuAer was not favorably disposed to this scheme as well, primarily because the long internal hangar and mechanisms required for the individual doors added considerable structural weight to the airship, reducing its useful lift. Although the hangar openings were capable of handling all existing single-engine naval aircraft, they would not be adequate for some of the larger types that were under design and expected to be entering service in the early 1940’s. Armed with initial positive experience from ZRS-7, BuAer rejected the airplane hangar altogether, requesting instead a revised design with aircraft stowed semi-externally on individual trapeze stations along the lower keel.
Goodyear-Zeppelin did not offer a new design incorporating BuAer’s recommendations. Instead, the firm provided additional calculations and anecdotal data to show that the efficiency of airship crews servicing and arming aircraft in a completely enclosed environment would outweigh
the weight savings gained by semi-external individual mountings.
The Navy was not pleased with Goodyear-Zeppelin’s reaction. Admiral Moffet then directed BuAer to request an outside ZRCV design competition which would not include Goodyear-Zeppelin. The Navy knew full-well that Goodyear-Zeppelin was the only American firm with the detail design capability and manufacturing plant capable of providing the US Navy with rigid airships, but felt that this step would prompt the Ohio firm to adhere more to BuAer’s demands in the future.
In fact, the competition produced several interesting outside proposals which, if the respondents had their own manufacturing capability, might have been seriously entertained. A total of ten proposals were received of which three were considered to have sufficient merit to warrant detailed design studies
As with the original competition that led to the ZRS-4 and her sisters, a proposal was offered by Dr. Karl Lanz of the WW1-era Schutte-Lanz airship firm in Germany. Lanz proposed to partner with an American firm (presumably Goodyear) to produce the airships if his design was accepted.
Lanz’s design was very similar to the ZRCV-B, although it varied in a few highly visible, but superficial, details. This airship was not looked upon favorably by BuAer, officially because it was very similar to the Goodyear proposal that had already been rejected. Further, the close similarity between the two proposals indicated to some BuAer reviewers that Lanz might have been working in collaboration with Goodyear, perhaps less to be the selected design contractor himself than to further document the advantages of Goodyear’s concept, presumably from a respected outside source. This suspicion is clearly evident in the following quote from an internal BuAer memo:
“…Not only does this [Lanz] design propose the same aircraft handling scheme we already rejected, our evaluation of the detailed schematics, show over 70% direct commonality with the Goodyear design. Hangar layout is is virtually identical, down to the placement of emergency lights, aviation fuel tanks and lines, and electrical wiring. Crew quarters are disposed similarly. The external engine cars are virtually identical in location, size, and internal layout. In fact, most of the main differences between this proposal and Goodyear’s ZRCV-B are cosmetic – fin and overall hull shape – differences in appearance that mask the overall structural and detail design similarities. It is our opinion that Lanz has either produced a thinly disguised copy of the ZRCV-B for his own purposes or is working in collaboration with Goodyear-Zeppelin…”
A more promising offer was made by a British team under Barnes Wallis and Neville Shute Norway of Vickers. Wallis assembled many of the original design staff responsible for the British rigid airship R-100, and had secured an arrangement to construct a prototype ship at Cardington. Had Vickers’ proposal been accepted, they also proposed to contract with Goodyear-Zeppelin for large-scale production.
In this case, however, there was clearly no collusion with Goodyear. The British entry borrowed much from the original 5,000,000 cubic foot R-100, including its geodesic internal bracing and relatively few longitudinal main girders. Instead of an internal aircraft hangar, the British design featured a long external aircraft handing gondola extending directly aft from main control station. Seven aircraft were arranged in tandem, each on its own trapeze system. In essence the aircraft were mounted externally from the main hull structure, but pilots and service personnel could access cockpits and engines from the fully enclosed gondola and walkways.
This approach avoided the awkward system of individual hangar doors proposed in the ZRCV-B, while still providing a largely enclosed space for most aircraft maintenance and servicing activities. BuAer found many elements of this proposal interesting and worth further study, but in the final analysis the Navy was uncomfortable sourcing the design of its next series of airships to a non-American designer. Also, some reviewers felt that the R-100’s structural scheme, which differed in many respects from “traditional” zeppelin or US practice, had not really been proven during the few short test flights and single Atlantic crossing the ship made before it was dismantled.
From the design perspective alone, the most interesting offer came from Metalclad Aviation, a successor to to the US Aircraft Development Corporation of Detroit, Michigan. This firm had designed and produced the small and revolutionary ZMC-2 rigid airship for the US Navy in 1927. The ZMC-2 was truly unique in that it completely abandoned the traditional fabric covered duraluminum zeppelin framework in favor of a stressed-aluminum skin, with only minimal internal bracing. Such a system was both lighter and less resistant to wear and tear than the traditional zeppelin framework, evidenced by the fact that ZMC-2 was still in active service almost 10 years after its first flight, and throughout its career suffered from far less osmotic gas loss that the Navy’s blimps or rigid airships.
Metalclad’s proposed ZRCV was in essence a massively scaled-up but less rotund ZMC-2 with a long external gondola for aircraft handling similar in concept to that offered by the British design. Like ZMC-2, the proposed Metalclal ZRCV eschewed the traditional fixed cruciform fins with elevators or rudders in favor of an interlinked system of eight separate movable control services.
Although BuAer felt that the Metalclad design had much to commend it, reviewers recommended that the Navy would be unwise to build a series of large operational airships on a design which had only been successfully demonstrated on a small prototype. However, the Metalclad concept showed enough promise to warrant further evaluation.
Although unwilling to accept Metalclad’s proposal for the current ZRCVs, BuAer proposed the procurement of one 3,000,000 cubic foot Metalclad training airship in 1941. These plans were put on hold and then cancelled by the outbreak of the Second World War. In any event, BuAer’s hesitancy about switching to the Metalclad concept was eventually borne out by the ZMCW-1 crash in 1965, which could be directly attributed to the lack of redundancy and rigidity inherent the metal clad principle.
Not surprisingly BuAer concluded that none of the outside proposals offered the combination of design quality and immediate constructability that the Navy needed and which Goodyear could provide. However, as expected, the review team liked several features of the Vickers and Metalclad designs, particularly the provision of individual aircraft service and launching facilities unburdened by hangar doors or other movable enclosures.
When informed of the results of the study, and certainly eager to protect their place as the US Navy’s only source of large airships, Goodyear-Zeppelin finally produced a design study that fully met all of BuAer’s requirements: ZRCV-C. With a few minor alterations, this design became the basis for all ZRCV ships completed before and during the Second World War.
Structurally, the ZRCV-C was similar to the rejected ZRCV-B, with the principal difference relating to aircraft handling, Rather than the long internal hanger in the earlier design, the ZRCV-C borrowed from the existing ZRS-7 and featured a series of 10 individual aircraft trapeze stations located in tandem beneath the hull to service, launch, and retrieve airplanes. As in the ZRS-7 the airplanes would be carried on their own trapezes partially outside of the hull, only the cockpit and upper fuselage being readily accessible from an enclosed area.
Although this would complicate aircraft access and maintenance when biplanes or high-wing aircraft were operated, BuAer presumed at the time that future aircraft embarked on the ZRCVs would be most likely be low wing monoplanes. As later events proved, this presumption was incorrect. By 1943, the main ASW attack aircraft on all ZRCV ships was the high-wing Harrier flying boat, which necessitated external stowage of virtually the entire aircraft, service being achieved by retractable crew and equipment baskets. Although this worked sufficiently well, Harrier servicing and maintenance on a ZRCV remained an uncomfortable and potentially hazardous task for service crews, requiring the airship to be flown at 20kts or less when being done.
In the 1938 naval appropriations bill, funding was authorized for 10 ZRCV ships to be completed over the following four years. The first two, ZRCV-1, USS Tulsa, and ZRCV-2, USS Intrepid, were commissioned in 1940. Also in 1940, as part of the overall military buildup authorized by President Roosevelt, construction of all commercial airships was suspended and the ZRCV program was accelerated. ZRCV-3, USS Anchorage, ZRCV-4, USS Sacramento, and ZRCV-5, USS Bon Homme Richard were completed in 1941. All five ships were based at Lakehurst, and before US entry into the war, they were clandestinely providing ASW air cover for Britain-bound convoys under the guise of “operational training”.
The 1938 Training Airship Program
Once all 10 ZRCV’s were scheduled to be fully operational in 1943-44, the Navy anticipated relegating the three oldest ZRS ships (USS Akron, Wichita and Macon) to a dedicated training squadron. The sole airship used for crew training in the 1935-40 period, USS Los Angeles, lacked the ability to handle aircraft and consequently had no remaining value to an airship service whose raison d’etre had become carrying airplanes.
However, until the entire ZRCV fleet was in place, all ZRS ships would remain operational fleet vessels. As an interim solution, BuAer proposed two smaller aircraft-carrying training airships (the ZRN-class) in 1938. These would replace the old Los Angeles. However, the ZRN’s would be sufficiently modern and capable to serve in an operational capacity if the need arose.
The 1938 ZRN program was very controversial, both in the Navy and out.
Many flag officers questioned the need for dedicated naval training airships at all since one of the purposes for the original Airship Act and Goodyear-Zeppelin’s two existing commercial airships was supposedly to provide a pool of trained reservists for the naval airship service. Many in congress argued that the Navy already had several aircraft-carrying ZRS airships and that, surely, at least one of them could be repurposed as a crew trainer with no additional appropriations
Others, supported by no less a figure than President Roosevelt, felt that the ZRN ships were far larger and far more capable than necessary for mere training purposes. Why, they asked, did the proposed ZRN have to be a 4,000,000 cubic feet ship larger than the famous Graf Zeppelin I that flew around the world? Why did it have to operate three airplanes? Why did there have to be two airships? Roosevelt, never a big supporter of the Navy’s rigid airships, clearly believed that the entire ZRN program was a backdoor attempt by BuAer to expand the Navy’s operational force of fleet airships beyond the numbers authorized by Congress in 1938, merely by calling two of them training ships.
The President then ordered BuAer to develop preliminary designs for the shortest, smallest, and least expensive airship that could provide the Navy with basic training in the operation of airships and hook-on aircraft. BuAer dutifully developed two alternative designs, each for an airship of approximately 1,000,000 cubic feet. One was a small, rotund, zeppelin-style rigid airship with space for a single airplane landing/service station in the lower keel immediately aft of the control car. The other was 1,200,000 cubic foot metalclad airship with the control car itself containing hook on facilities for a single airplane.
These designs demonstrated that an airplane-carrying airship built to the smallest possible dimensions was worse than no airship at all. The traditional zeppelin design would be only marginally less expensive than the planned ZRN, but have far less capability. The metalclad, with its stressed skin envelope, would have little value for training flight personnel in the inspection and maintenance of the Navy’s existing and planned fleet of zeppelin-style airships. Armed with this information, Admiral William Moffett eventually succeeded in convincing Congress and the President to fund both ZRN airships as originally proposed, and they were included in the final 1938 Naval Appropriation.
Both ships were built by Goodyear-Zeppelin to a design prepared by C.P. Burgess of BuAer. ZRN-1 USS San Juan was completed in early 1940, followed by ZRN-2 USS Austin in mid-1941. With a gas capacity of slightly under 4,000,000 cubic feet and a length of 710 feet, the ZRNs had trapezes and launching stations for 3 aircraft. Despite President Roosevelt’s suspicions, the Navy never gave any thought to incorporating either ship in the active fleet during the Second World War. Both ships were based at Sunnyvale, which became the principal training station for the naval airship service. The ships spent the bulk of the war at Sunnyvale until the rigid airship program was disbanded.
The Second World War
Developing a New Operational Doctrine
It was only with the ZRCV ships that the rigid airship came into its own as a serious component of the United States Navy. However, until the outbreak of the Second World War, their raison d’etre was still poorly understood.
Following the attack on Pearl Harbor in December 1941, the Navy’s priorities changed. Aircraft carriers and airplanes assumed highest priority, and even those supportive of the airship believed the ZRCV program should be curtailed. Only two ZRCVs already nearing completion were finished: ZRCV-6, USS Honolulu, and ZRCV-7, USS Manila Bay. The remaining three ships were cancelled. Many airship building sheds were transformed into assembly plants for a variety of naval aircraft. However, design work on the “next generation” ZRCV continued, and three sheds at Goodyear were reserved for the repair, refitting, and modification of the operational airships.
Prior to 1940, BuAer, as well as many of the most senior officers in the Navy’s lighter-than-air sections, initially saw the ships’ prime function in terms of the 1937-1938 Pacific Fleet Problems, most of which were designed with Japan as the likely enemy. Both USS Akron and USS Macon participated in these exercises, which amply demonstrated the ability of the aircraft-carrying large rigid airship as a fast, long range, scout. The ZRCVs presumably would have given this long range reconnaissance wing a credible offensive capability as well.
All of these plans were predicated on the Navy’s decades-old “War Plan Orange”, which presumed that, in the event of war with Japan, the small US Navy Asiatic squadron and unfortified advanced bases would be overwhelmed fairly early in the campaign. This would force the main Pacific Fleet to steam west across the Pacific from Hawaii to either contest ongoing Japanese invasions in the Philippines, or barring that, seize bases in the Marianas from which it could begin the gradual economic blockade of Japan. It was presumed that in either case, the Pacific Fleet would have to defeat the Japanese Navy in a decisive engagement south of Japan, probably relatively early in the campaign.
In this context, the ZRCV’s would operate with light cruisers and aircraft carriers as a fast scouting screen in advance of the US main battle line and its support train as it steamed westward from Hawaii. Their role would also be to locate and assist in the destruction of any Japanese submarines that were expected to be lying in wait for the US force along its route.
It was presumed that the ZRCV’s would likely be lost if they chanced upon Japanese aircraft carriers, although airship advocates offered the promise that the airships’ small strike force of dive bombers could exact some retribution by damaging the Japanese carriers, and limiting their usefulness as scouts or offensive weapons in the fleet action followed.
As later events in the Pacific showed, this was not a specious argument. Under existing Japanese doctrine that focused on a single “decisive battle”, the IJN’s aircraft carriers were not designed, nor were they expected, to take battle damage and maintain an operational capability. They were designed essentially as “first strike” weapons whose key purpose was to locate and destroy US aircraft carriers in the initial stages of the expected fleet action, and then hopefully assist the battlefleet by providing aerial reconnaissance and conducting additional airstrikes on the enemy with whatever surviving aircraft they had. Key to success was the presumption that Japanese carriers could strike first before they received damage that rendered their own flight decks or hangars inoperable
The 1942 Battle of Midway and later actions would abundantly demonstrate that IJN aircraft carriers were probably even more susceptible to crippling damage from a few bomb strikes or torpedo hits than anticipated. Given this, one must wonder what might have happened if even a single solitary ZRCV on picket duty had encountered the Japanese Pearl Harbor strike force on the western approaches to Hawaii.
Because airships had less endurance than surface ships, the Navy in 1936-1938 converted three fleet oilers, USS Richland, USS Howard, and USS Stennis, to serve as airship tenders. These were similar to, but larger than, the old USS Patoka, each with a large high mast and ample supplies of helium, fuel, and other supplies to allow the airships to operate for extended periods with the fleet.
Prior experience with Patoka had been limited to sheltered harbors or bays. Experiments in 1938 with the ZRS USS Wichita showed that mooring and servicing a rigid airship from a tender on the open sea was an unreliable proposition. It was often impossible to moor the airship in anything but the calmest seas. In addition, even when the Wichita had been successfully moored, she was forced to uncouple several times to avoid damage when sea and wind states conflicted.
Experiments to use the obsolescent aircraft carrier USS Ranger as a base for airship operation avoided the mooring difficulties, but the airship could not be “docked” to the carrier’s deck, requiring it to be in full flight status while taking on fuel or ballast. In the late 1930’,s underway replenishment of surface ships was still an experimental and dangerous process, and this was when both vessels were operating in the same fluid medium. In the case of airships and a surface replenishment ship, the vessels are within completely different fluids, making their chance of breaking fuel lines or even colliding with each other far more likely. And the collision of a rigid airship with the upper works of a surface vessel would almost certainly be fatal to the airship.
As a result, the Navy decided that it would be necessary to station tenders in sheltered advance locations such as Midway Island, Wake Island, or (rather optimistically) the Japanese occupied Marianas. In fact, the virtual impossibility of effectively servicing rigid airships at sea was one of the reasons the decision was finally made in 1940 not to station any airships with the Pacific Fleet in Hawaii.
The following excerpt from BuAer Report 1939.A offers a succinct discussion of the matter:
“The airship’s abilities and drawbacks are such that it can never hope to be the advanced fleet scout the Navy had in mind in 1935-36. No way has yet been found to provide replenishment to airships operating for extended periods at sea.
Although far faster than surface scouts and aircraft carriers, airships will be unable to operate for any extended duration with the Fleet once it enters the western Pacific, unless advance stations in Wake Island, Guam, or the Philippines, are still available. If they scout ahead at their cruising speed of 60kts, they will arrive in the Western Pacific well ahead of other fleet assets, and may find the bases at which they hope to replenish occupied or under siege by the enemy. In addition they would be subject to attack by enemy naval or land-based aircraft with little means of self-protection. The airships would then be forced to return to Hawaii or perhaps Midway for replenishment and be unavailable to provide tactical scouting for the fleet when it arrives. As a result, the only real use of the Navy’s rigid airships in the Pacific would be in a maritime reconnaissance role once suitable bases are built or recaptured or in an ASW capacity in the central and eastern Pacific. Attention is drawn to USS Macon’s success in the recent Midway problem, in which she was very successful spotting the submerged submarines USS Cockle and USS Snapper and keeping them under observation for much of the exercise.
This would appear to be the best current use of the new ZRCV ships currently under construction. Whether the ships are based with the Pacific or Atlantic Fleet should be determined based on diplomatic and geopolitical developments this study is not intended to address”
The BuAer report was completed in October 1939, after the outbreak of the European War. Although at the time the US had adopted a policy of strict neutrality, both the Navy and the Army (especially the Air Corps) were developing strategic plans to address the contingency of possible war with Germany. For the US Navy, this once again meant having to face the specter of German submarines engaged in unrestricted warfare against US trade and commerce in the Atlantic. As events transpired in 1940 and early 1941, this was proven out even before the United States was thrust into the Second World War.
Basing, Facilities, and Organization.
Initially, with the exception of training airships based at Sunnyvale NAS in California, all rigid airships were operated in the Atlantic theatre of operations. Several major bases and a number of secondary facilities were developed for the rigid airship service
Lakehurst Naval Air Station The primary rigid airship base throughout the war was Lakehurst Naval Air Station, New Jersey. It was administrative home of the entire US Navy Airship Operational and Research Commands throughout its existence and was also the designated home port for all rigid airships active in the Atlantic theatre of operations. The base was initially commissioned in 1921 and had been expanded in 1935-41. By 1942, Lakehurst NAS comprised three new double hangars capable of sheltering up to six rigid airships simultaneously, several low mooring masts and circles on which additional ships could be grounded while waiting for space in the hangers, and the complete range of airship support facilities.
The original 1921 Hangar No.1, as reconstructed in 1939, was capable of sheltering one ZRCV or ZRS-class ship or two smaller ZRN’s. Lakehurst Hangars No 2, 3, and 4, completed in 1938-41, were massive twin structures designed to shelter two ZRS or ZRCV-class ships each. Lakehurst NAS also possessed landing strips and sheds for the airships’ HTA units. During the war, the airfield was expanded to handle the complete range of land-based aircraft operated by the USN.
Norfolk Naval Air Station In 1940 a single twin hangar for ZRCV ships was completed at the Norfolk NAS in Virginia, supplemented by a complete shop capable of maintaining, repairing and servicing the airships. In 1941-42 two ZRCVs, USS Sacramento and Tulsa, were detatched to Norfolk where they could coordinate closely with other naval aircraft and ships struggling to counter Germany’s “Operation Drumbeat” U-boat offensive off the US east coast. After early 1943, no rigid airships were permanently based at Norfolk, although the hangars were often used by ZRS and ZRCVs on temporary details.
Sunnyvale Naval Air Station Prior to 1940, Sunnyvale NAS in California was being developed as the home base for the large number of rigid airships planned for the Pacific Fleet. Consequently, Sunnyvale possessed a capacity well in excess of what it eventually needed as an LTA training facility. This comprised two large twin hangers for four ZRS or ZRCV ships as well as its original single hangar built for USS Macon. With the consolidation of the Naval Airship Operational Command at Lakehurst, only the original Hangar No. 1, which could just fit both smaller ZRNs, was kept in service. One bay of Hangar No. 2 was kept active as an airship maintenance and repair shed. Remaining hangars and all other base facilities were refitted to house non-rigid airships as well a variety of other naval aircraft operating from the large airfield.
Goodyear-Zeppelin Airdock (“Akron NAS”) In any discussion of “major airship facilities”, mention must also be made of the Goodyear-Zeppelin Airdock, in Akron, Ohio. By 1941 the Akron complex consisted of two giant double fabrication hangars capable of constructing four ZRCV ships concurrently, one operational hangar for a ZRCV-class ship, the original Goodyear-Zeppelin ZRS construction hangar, and numerous other facilities devoted to the construction, repair, and maintenance of the Navy’s rigid airships and blimps. During the war, Goodyear also became a major builder for US naval aircraft, particularly Grumman Wildcats and Vought Corsairs. This necessitated the addition a large airplane manufacturing plant and a military airfield. By 1945, the Goodyear Airdock had become the largest single privately- owned aircraft manufacture and maintenance complex in the United States.
Although the Goodyear-Zeppelin Airdock remained a private corporate facility, the close – many would say incestuous - relationship between Goodyear and the US Navy’s airship establishment meant that Goodyear’s airship works often functioned as a naval facility. Not only did Goodyear build all of the Navy’s airships, their initial test flights and final pre-acceptance shakedown cruises under mixed Goodyear-Navy crews were based at Akron. In 1941, the Navy established a small administrative facility immediately adjacent to the Goodyear Airdock, consisting of barracks for officers and enlisted personnel, administrative offices, preflight school for both LTA and HTA crews, and other support staff. This was duly commissioned the “Akron NAS” although it neither few, built, nor maintained any naval aircraft.
Mirroring the Navy’s practice of satellite bases for its principal training and operational bases, Goodyear also maintained mooring masts at several company properties throughout the central USA and in Amarillo, Texas, where much of the helium used in the airships was produced. The Navy often used these outlying Goodyear properties as destinations for long-distance shakedown cruises before officially the accepting rigid airships into service.
Secondary Airship Bases
In addition to the above major facilities, the Navy constructed a number of secondary airship bases for its rigid airships, a number of which featured a large “temporary” wooden hangar capable of housing a ZRCV-sized ship, a single mooring mast and mooring out circle, and replenishment facilities. Unlike the primary bases, the secondary facilities had limited maintenance capability and were not equipped to repair substantial damage to the ships or their aircraft.
At wartime peak in 1944 there were five outlying secondary bases in the US with rigid airship hangars and most necessary supply and replenishment facilities. These, together with other facilities, also served as home bases for the Navy’s large fleet of small blimps used in air-sea rescue and coastal ASW work. Although the blimps were provided their own hangars on some bases, this was not always the case, a condition that on occasion resulted in operational or logistic difficulties.
Pensacola NAS, Florida boasted one large wooden hangar capable of sheltering and servicing two ZRCV or ZRS ships on detached duty and was also the home base for two blimp patrol squadrons. ZRCV and ZRS ships often operated from Pensacola. In addition to its LTA support role, Pensacola was a major base for land-based patrol aircraft, pilot training, and flying boat operations. Its location in Florida was ideal to provide ASW coverage in the Atlantic, Caribbean, and Gulf of Mexico.
Ceiba NAS, Puerto Rico contained a large wooden hanger capable of sheltering and servicing one large rigid airship, but only limited maintenance and repair facilities. Although originally intended as a temporary base of rigid airships on detached duty, it also served primarily a home base for blimp ASW and Air-Sea Rescue squadrons, eight of the smaller non-rigid airships usually being housed in the large hangar. Rigid airships were never based at Ceiba for any extended periods, and even temporary use of the base by rigid airships was discouraged because of logistical problems, a fact that was brought home by the USS Honolulu landing accident in 1943.
South Weymouth NAS, Massachusetts was one of the navy’s chief blimp bases, but also boasted a single large steel hangar and mooring out circle capable of handling a ZRCV airship. Like Ceiba, South Weymouth never hosted rigid airships on extended stays, primarily because of its relatively close proximity to Lakehurst. At various times, USS Wichita, USS Sacramento, and USS Intrepid operated from Weymouth.
Tillamook NAS, Washington boasted two large airship hangars capable of handling, servicing, and sheltering ZRCVs. It was originally commissioned as an operational satellite base for Sunnyvale NAS. However, when all fleet airship operations were moved to Lakehurst, Tillamook was repurposed for ASW and Air Sea Rescue coastal blimps and aircraft. Occasionally one of the ZRNs from Sunnyvale would conduct training flights to Tillamook, but it never hosted a rigid airship.
Houma NAS, Louisiana contained two large airship hangars suitable for use by ZRS or ZRCV airships. It was ideally located for airships and other aircraft undertaking ASW and Air Sea Rescue operations off the busy mouth of the Mississippi River, a common target area of U-boat activity early in the war. The facility was also a very active blimp base. At one time or another in 1942-43, USS Akron, USS Macon, USS Belleau Wood, USS Honolulu, and USS Bon Homme Richard were detatched to Houma. However, only Macon ever stayed for an extended period at Houma.
Non-US Facilities
Bartolomeu de Gusmão, Brazil. The commercial Zeppelin hangar at this airport near Rio de Janeiro was the only modern airship facility in the western hemisphere outside of the US. After Brazil entered the Second World War in 1942, the Brazilian Air Force made the facility available as a distant basing option for US rigid airships patrolling the South Atlantic. Several additional smaller hangars were built to house a number of blimps that also operated from the facility. Because of its fully equipped zeppelin hangar and complete servicing facilities, “Barty” was well suited for US rigid airship operations. Several ships, particularly USS Belleau Wood (the former German Graf Zeppelin II and one of the ships for which the Brazilian hangar was specifically built) were frequently detached there. In fact, Belleau Wood so often operated from Bartolomeu de Gusmão that the US gave serious consideration to transferring the airship to the Brazilian Air Force under lend-lease. Accordingly, prospective Brazilian LTA flight and ground personnel were trained at Sunnyvale NAS, graduating in early 1945. However, by then the war was nearly over and, given the reduced enemy submarine threat, Brazil no longer desired the airship and the plan was cancelled.
Other Facilities At one time or another during the war US rigid airships, including the ZRN training squadron, made use of temporary mooring mast facilities erected in Hawaii, Cuba, Iceland, the Panama Canal Zone, Gibraltar, Casablanca, Midway Island, and Guam. Ships were never based at these sites; they were only used as way stops, or in the case of ZRNs training destinations. After the liberation of France in 1944, the prewar French naval airship base at Cuers-Pierrefeu near Toulon became available to US airships. During the last months of the war, Toulon often served as an extended way stop for US rigids on transatlantic sweeps despite the fact that its hangars were not quite long enough to completely enclose a ZRCV. It was, however the most suitable existing European site for his purpose. Although Britain retained number of large airship sheds from its 1920-31 airship program, the Navy never considered using them, in large part because southern England remained an occasional target for Luftwaffe raiders (and later V-1 and V-2 missile attacks) until the end of the war.
Organization
In 1942, the Navy’s LTA program was divided into three overall Commands.
The Naval Airship Training and Reserve Command was centered at Sunnyvale NAS and was responsible for all aspects of LTA training and recruitment. Three largely independent training programs existed for Rigid Airship Training Services, Non-Rigid Airship Training Services, and Ground Support Services. Separate from the above units, both ZRN airships, as commissioned ships under the command of their own Commander and Executive Officers, comprised the Naval Airship Training Squadron.
The Rigid Airship Operations and Research Command based at Lakehurst combined three Divisions: the Base Operations Division responsible for building, maintaining, supplying, and staffing all airship bases, a Research Division responsible for coordinating all research relating to the design and operation of rigid airships and their associated equipment, and three Rigid Airship Patrol Squadrons consisting of all the commissioned airships, each ship under the command of its own captain (usually a Commander in formal rank) and executive officer.
The Non-Rigid Patrol Airship Division was very much a stepchild, despite the large numbers of blimps (over 75) eventually procured by the US Navy during the war. Blimps were treated as aircraft, not commissioned ships in the US Navy. Thus, whereas effective commanding and executive officers of a rigid airship would accrue promotion credit toward captaincy of larger surface ships and eventual flag officer status, this avenue was not available to the men (usually lieutenants or even ensigns) who commanded blimps. Individual blimps were assigned as needed to patrol squadrons (ZNPs) based at the many rigid and non-rigid airship bases, with the primary functions being near- coastal ASW patrol and air-sea rescue. Blimp operating doctrine specifically discouraged these craft from initiating combat with enemy submarines unless the U-boat constituted an immediate threat to a merchant ship or the airship itself. Because of these limitations and the existence of 12 operational rigid airships, many in the Navy questioned the very rational for the large blimp fleet at all. However, if the log books and reports of German submarine captains are to be believed, the sight of blimps (often referred to as “dwarf Zeppelins” by the Germans) often forced submarines to submerge and break off pursuit of convoys, possibly saving countless lives.
Operations
Regardless of where rigid airships might operate, they were all assigned to one of three Rigid Airship Patrol Squadrons home based at Lakehurst NAS or to the Naval Airship Training Squadron based at Sunnyvale NAS. Although all three patrol squadrons called Lakehurst NAS their home, each had largely non-overlapping operational areas of responsibility.
Rigid Airship Patrol Squadron 1 (ZRP-1) comprised the 4 US-built ZRS-class ships, USS Akron, USS Macon, USS Wichita, and USS Newark. ZRP-1’s home base was Lakehurst. Since its ships were significantly smaller, shorter ranged, and less capable than the ZRCV ships, ZRP-1 typically operated on convoy escort, air/sea rescue, and ASW duties in the western Atlantic and Gulf of Mexico. Individual ships were often detailed to secondary bases in Florida, Puerto Rico, or Texas, where they sometimes operated in so-called “hunter-killer” groups with detached ZRCV ships. Late in the war, USS Akron was detached to Sunnyvale NAS and ended the war operating from Guam. Other than Akron, ZRS-ships rarely operated from overseas bases.
Rigid Airship Patrol Squadron 2 (ZRP-2) included the ZRCVs USS Tulsa, USS Intrepid, USS Anchorage, and USS Sacramento. ZRP-2’s ships were all home based at Lakehurst, but detached units were often detailed to satellite facilities in Norfolk or Weymouth for extended periods. From these bases as well as temporary masts in Iceland, ZRP-2 provided convoy escort, air/sea rescue, and independent ASW work primarily in the north Atlantic sea lanes.
Rigid Airship Patrol Squadron 3 (ZRP-3) consisted of three ZRCVs (USS Honolulu, USS Bon Homme Richard, and USS Manila Bay) and the former German airliner USS Belleau Wood. ZRP-3 was also home based at Lakehurst. However, ZRP-3’s principal theatres of operation were designated the Gulf of Mexico, Caribbean, and South Atlantic, where they served primarily in the ASW hunter-killer role, either independently or in concert with other airships, surface units, or aircraft. Ships of ZRP-3 often spent extended time at secondary bases or masts in Puerto Rico, the Canal Zone, and Brazil. Belleau Wood, in particular, was often detailed to Bartolomeu de Gusmão in Brazil. The hanger there had been specifically designed for her and her sister Hindenburg when she was a commercial German airship, making it well suited as a nearly permanent base-of-operations for the ship.
Naval Airship Training Squadron The two US-built ZRNs spent the entire war assigned to Sunnyvale NAS, California, although long distance training flights often saw them based temporarily at secondary facilities in Oregon, Washington, the Canal Zone, and Hawaii. While training over 1500 seamen and HTA aircrew for the airship service, they also conducted convoy escort missions between California and Hawaii under virtual wartime conditions. After 1944, both ships were outfitted with advanced air-search radar and were utilized in the unpublicized defense against Japanese balloon bombs, a number of which were destroyed by the airships’ own HTA training units.
Non Rigid Airship Operations
Although not the subject of this study, the US Navy also made considerable use of non-rigid “blimps” in ASW and air-sea rescue work. These craft, considerably smaller than the rigid ships, were considerably less expensive to build and man, and were ordered in large numbers from Goodyear aviation. The most common “K-class” airships operated only from the mainland USA and were chiefly responsible for patrolling US coastal waters and conducting ASW searches in the areas of convoy assembly points. Far too small to carry aircraft or more than small number of depth bombs, the blimps’ principal role upon sighting an enemy submarine was to call surface help and maintain station over the target. In practice, they eventually served primarily as coastal patrols and in the air-sea rescue role.
The Overall Performance
Prior to late 1943, rigid airships in the Atlantic only operated within their out-and back radius of action (roughly 3000 miles for the ZRS ships and 5000 miles for the ZRCVs). While all the ships were fully capable of transatlantic convoy escort or patrol missions with fuel to spare, the only suitable basing and hangar facilities not in German hands were in England, and even here, the Navy did not want to risk its airships in the relatively congested airspace of northwestern Europe where they could be subject to Luftwaffe attack, either on the ground or in transit.
With the successful Anglo-American invasion of North Africa, transatlantic ASW missions became possible. Temporary mast facilities were erected at Gibraltar, and by late 1944, after the liberation of France, ships could put in at the old French naval airship base near Toulon.
It is probably not an exaggeration to say that US rigid airships were as instrumental in securing ultimate victory in the Battle of the Atlantic as any other naval aviation assets. They and their hook-on planes provided a degree of 24-hour aerial coverage in the vicinity of convoys which was unmatched by either land-based air or escort carriers. They could launch and retrieve their planes when sea conditions made operation from small escort carriers impossible.
However, the airship (both rigid and non-rigid) was really not ideally suited to close convoy escort. Airships were highly visible from a surfaced submarine at long distances. This frequently allowed submarines to locate and converge on convoys under close airship escort in situations where the merchants might otherwise have gone unnoticed. Also, the close proximity of a visible ZRCV to convoys at times had the opposite, equally unhelpful effect, of making a submarine abort a possible attack when effective escorts were present that could destroy the U-boat.
As a result, the operating doctrine for rigid airships shifted away from close escort to independent patrol and the hunting and killing of U-boats. This was particularly their role in the mid-Atlantic “gap” outside the range and endurance of most shore-based ASW aircraft. Also, airships could conduct sweeps and patrols at night and in poor visibility conditions that grounded many most other aircraft. ZRCVs could also operate their aircraft when rough sea conditions made operations from small escort carriers problematic. As patrol vessels the airships’ relatively high speed in comparison to surface ships and extremely high endurance in comparison with aircraft played real dividends.
From 1943 on, the airships were equipped with the largest and longest ranging air/sea search radars, towed and buoy sonar and hydrophones, and magnetic anomaly detection (MAD) equipment. The ZRCV-class ships were, in particular, well-armed with depth bombs, standard bombs, and other anti-ship weapons, both for use by their hook-on airplanes and the airship itself. Toward the end of the war, acoustic homing torpedoes were added to this arsenal. As a result, the ZRCVs were more than capable of both finding and pressing home attacks on submarines.
Because of their long endurance, the airships could loiter on ASW searches in the “gap” for up to a week, and although their attack planes had limited range and relatively poor offensive capabilities in comparison with their land-or carrier based counterparts, they could be rearmed and refueled by the airships while on station. For these reasons, being located, tracked, and engaged by a ZRCV was one of a u-boat commander’s worst nightmares.
Although the older ZRS type ships had to rely on other aircraft or surface units to engage and sink German submarines, they and their aircraft were excellent in the reconnaissance role. They also possessed an endurance almost equal to that of the larger ZRCVs. When appropriate, it was not uncommon to see a ZRS and ZRCV ship operate together in a hunter-killer capacity – the ZRS being one of two “hunters” and the ZRCV the “killer”.
Airships also proved to be less vulnerable to damage from submarines’ deck guns than had been feared. Unless a lucky hit was made on the control stations, engines, or fuel systems, a large rigid airship was virtually invulnerable to the standard anti-aircraft armament shipped by wartime u-boats. Even when such hits were made, severe damage never led to loss of the ships. In many, instances, airships would return to base with dozens of holes from 20mm, 37mm, and even 88mm shells that had passed harmlessly through the ship, in a few cases without its crew even being aware they had been hit.
Only once was a rigid airship almost downed by a submarine. This involved an engagement between USS Sacramento and U-367 several hundred miles off the Maryland coast in July 1942. Sacramento encountered the surfaced submarine on July 2, shortly after beginning a standard ASW patrol. She forced the submarine under and tracked her for several days, allowing the enemy to surface only briefly, at which time she used her aircraft to force her to submerge again. Up to this point the mission was going according to the textbook.
But then the submarine sprang a surprise on Sacramento. After being tracked and depth bombed by the airship’s aircraft, the submarine surfaced, issuing dark black smoke from its conning tower. Believing his foe was seriously damaged and possibly close to surrender, Sacramento’s commander elected to close for a direct engagement.
What he did not realize was that the smoke was a ruse, serving the double purposes of making the submarine appear damaged and masking the U-boat’s gun crews while they prepared their weapons. As she closed the range, Sacramento began to receive fire and was quickly struck by well-aimed cannon and machine gun fire. This destroyed both portside engine cars and peppered the immediately adjacent gas cells with shrapnel. In addition, the control car was struck by a combination of 88mm and 20mm fire, killing all 14 crewmen in the control car, including the ship’s Commander and Executive Officer. Assuming command from the aft emergency station, the Sacramento’s senior surviving lieutenant immediately broke off the engagement, while the only slightly damaged U-367 chose to escape rather than risk further combat.
Sacramento eventually reached Norfolk NAS on the power of only two of her original four engines, and losing critical amounts of lifting gas. To make land, she had been forced to jettison her entire compliment of aircraft (which, lacking conventional landing gear could not be flown off), all remaining weapons stores, all standard ballast and any unnecessary fuel. In spite of this and her sailmakers’ emergency repairs to the leaking gas cells, she was still heavy from loss of helium, requiring her to be flown at maximum speed with a 20 degree nose up attitude to maximize dynamic lift. Sacramento landed hard and incurred significant damage to her lower fin and bottom keel, requiring extensive repairs.
Almost certainly, had this action occurred in mid-Atlantic, the airship would have been lost. In a subsequent Board of Inquiry, Sacramento’s commander was faulted for being unnecessarily aggressive in seeking to bring a surfaced enemy into close action without first using his aircraft to determine the extent of damage and eliminate the submarine’s anti-aircraft capabilities. He was also faulted for pressing the engagement and not immediately seeking to disengage when the submarine opened fire. Her commanding lieutenant and 16 crewmen received the Navy Cross in recognition of their skill and courage in saving the damaged airship.
Immediately following the Sacramento inquest, the Navy issued orders prohibiting airships operating alone from attempting close engagements with surfaced submarines unless they had first used their onboard aircraft to destroy or disable all enemy anti-aircraft batteries.
Not unexpectedly, the U-boat’s crew was celebrated upon returning to Germany. The engagement was also featured in a late 1942 article in the Wehrmacht propaganda magazine Signal, titled “We destroy an enemy zeppelin”. In fairness, the U-boat captain’s belief that the attacking airship was destroyed was reasonable, given his perspective. However, as was typical for Signal, the propagandist went further and drew a number of strategic conclusions intended to demonstrate the desperate situation faced by the Allied anti-submarine campaign. Among these was an inference that the “destroyed” airship may have in fact been the former Graf Zeppelin leading to the implication that the Americans were driven to use such “flimsy” civil craft in naval patrols because of excessive naval losses in the Battle of the Atlantic and Pacific theatre. The article also contains the only known photographs of an American airship taken from the enemy perspective. One image of Sacramento drifting bow down barely 200 feet off the surface of the sea, dropping “debris and fuel” (actually ballast), smoking from one engine car, and clearly missing most of its control gondola is particularly striking (See appendix I for the complete text of this article).
Airships were not tested in air-to-air combat, another area in which they were presumed to be vulnerable. They never encountered Luftwaffe fighters or other well-armed combat machines. On rare occasions in the 1941-42 period, US airships operating in the eastern Atlantic came within visual range of lumbering Fw 200 Condor reconnaissance-bombers or the odd long-range German flying boat. US airships typically carried multiple .50 cal machine guns in the control car and on stations dispersed along the hull or in engine cars to discourage air attack. However, German patrol bombers never sought to engage US airships, probably because they themselves were weakly armored, poorly armed, and operating at the limit of their endurance when the contacts were made.
On three reported occasions US airships launched F3A fighters to drive away German aircraft, although the enemy planes were not destroyed. In one of these instances a fighter from USS Intrepid was severely damaged and had to ditch, its pilot being picked up by the airship.
One advantage of the ZRCVs was unexpected. As the war progressed and German submarines began to make greater use of search and anti-air radars, it became apparent that the giant airships, so visible to the naked eye, were less so to the radars of the day. Their diffuse aluminum structures and fabric envelopes tended to present a confusing radar signature completely unlike that of either airplanes or surface ships. Until this was understood, German radar operators frequently misinterpreted radar contacts with airships as flocks of seabirds or signal anomalies rather than potentially hostile warcraft.
It cannot be denied that the airships also had inherent flaws that could have been anticipated by anyone who participated in the peacetime fleet exercises of the late 1930’s.
In general, the reliability of visual sighting from the airships and their planes did not live up to the optimistic claims made by their supporters in the 1920’s and 1930’s. In good visibility, a giant airship typically operating at less than 4000 feet is far more visible to its enemy than the other way around, especially when the target is a small submarine. Prior to the widespread use of radar on the airships, German submarine commanders frequently noted with amazement how apparently close a US airship could cruise by without seeing their surfaced ship.
Similar problems affected visual scouting from the airships’ planes. Unlike their land- and carrier-based counterparts, which were often radar-equipped two-seaters, most airship-based scout planes rarely carried a dedicated observer or search radar. To make them even lighter, airship planes often had less fuel capacity. Since most of them did not have conventional landing gear, they could not land on aircraft carriers or at land bases, meaning they had to remain close to their parent craft.
Because of the above factors, HTA unit operating doctrine tended to be conservative and risk-averse. Only in general patrol, when the planes and airship followed preset courses and speeds to cover large expanses of sea, were airplanes operated far beyond the range from which they could see the airship. In most attack situations, when the airship was required to change course and speed to track a submerged submarine, attack aircraft were usually not launched until the airship itself was in visual range of the target.
The early impression that airships were vulnerable to weather conditions was also borne out by wartime experience. While airships were really not any more vulnerable to violent weather than airplanes, 1940’s era aircraft could operate at speeds and ceilings allowing them to avoid or limit their exposure to the worst conditions. Airships, on the other hand, could neither rise above a rapidly moving Atlantic storm front nor outrun it. Once in a significant storm, the airship was at the mercy of winds exceeding its maximum speed and sudden pressure changes that affected its bouyancy. Even the mere risk of strong weather often curtailed airship operations when fast-moving or high-flying airplanes could perform theirs. Two airships, USS Newark and USS Tulsa, were lost at sea with all hands as a direct result of violent weather. The loss of Newark was particularly tragic in that it occurred on May 7, 1945, after Allied victory in the European theatre.
Ground handling also remained a major Achilles’ heel of the rigid airship. In the best conditions and with mechanized assistance, landing and launching large airships was an involved process that required large ground crews. Even relatively mild winds at airship bases could delay or cancel what would otherwise be routine sorties or landings. This created the legitimate impression among many in the fleet that the airships were undependable and difficult to base when compared with other aircraft or surface ships.
The risk inherent in airship landing operations is best exemplified by an August, 1943 accident at Ceiba NAS in Puerto Rico which almost destroyed USS Honolulu. Just after completing a week-long ASW search Honolulu encountered deteriorating weather. Her commander elected to temporarily shelter the airship at Ceiba rather than continue on toward Norfolk or Pensacola. Suspecting that conditions would only worsen, he attempted the landing in unsettled conditions, with gusty winds and blowing light rain buffeting the air station. Initial ground crew operations were uneventful. The landing crews had secured the ship’s nose cone to the movable mast and were preparing to anchor the lower fin to the aft mooring out rails when the ship was hit broadside by a sudden and unexpectedly forceful gust of wind. Because many of the ground crew had loosened their hold on the mooring lines, the remaining men attending the aft fin immediately lost control of the ship and the incompletely secured fin was ripped from its moorings.
Honolulu immediately began to vane, dragging the fin around the circle. After the ship finally came to rest parallel with the prevailing winds the lower fin was virtually destroyed, and the overall integrity of the ship’s structure was in question. The airship was eventually brought safely into the hangar, but it was clearly in no condition to risk a return flight to Lakehurst once the weather cleared. The Navy initially considered writing the ship off as a total loss but eventually decided to attempt repairs in the Ceiba hangar, a task for which the hangar was unsuited. Goodyear design and construction staff together with specialized jigs and tools needed to be brought in. Repairs required the aft end of the ship from frame 3 to be reconstructed. Not only did this eliminate the hangar’s use for other ZRCVs, ZNP-14, a non-rigid airship patrol squadron normally based at Ceiba, lost use of the hanger and was disbanded, essentially eliminating the base as a functioning ASW facility for over six months.
The Pacific
As noted, the Navy initially saw no reason to deploy combat airships to the Pacific. Unlike the Atlantic theatre, where the Allies generally enjoyed control of the air, Japan had an extremely effective naval air arm and a history of using it very aggressively. The Navy believed that rigid airships would be extremely vulnerable to Japanese carrier aviation if operated in any active combat zones of the western Pacific. Extensive use of floatplane fighters and the very long range of many Japanese aircraft also added to the Navy’s hesitance to risk its costly airships in the Pacific. Finally, even though Japan had a large and capable submarine fleet, Japanese submarine doctrine virtually ignored commerce raiding. Only rarely did Japanese submarines operate off the US Coast. There was thus little need for the ZRCV or ZRS ships airships as convoy escorts or ASW hunter-killers. The other prime role for airships was air-sea rescue and harbor patrol flights, task that could be adequately handled by blimps, Catalina flying boats, or the two ZRN training ships at Sunnyvale.
However, in early 1944, after the Japanese carrier fleet had been largely eliminated and the worst of the German U-boat threat in the Atlantic had apparently passed, the oldest ZRS ship, USS Akron, was unexpectedly detailed to the Pacific Fleet and flown to a temporary mast erected at Kanoehe Naval Air Station in Oahu, Hawaii.
The rationale for this deployment has never been fully explained. Not only was there was little need for Akron’s services in Hawaii this late in the war, the ZRS ships were far less suitable for Pacific duty than the larger ZRCVs. Politics was almost certainly the reason for this strange deployment
USS Akron was commanded by a young officer from an influential New England family with strong connections in the Democratic Party. In two previous years, Akron had amassed an excellent operational record, but this was less visible than the sinkings of U-boats reported by the more capable ZRCV-class ships. It was perhaps thought by some that Akron (and its undeniably capable 27 year old commander) might have more opportunity for public acclaim if it was the only ship of its type in the theatre.
As events transpired, this is exactly what occurred. Akron capably provided ASW scouting and air/sea rescue activities between Hawaii, the Marshall Islands - and farther west as the Japanese Empire shrank. Then she moved on to Guam.
Finally just a few days before the end of the Pacific War, Akron accidentally stumbled on over 700 survivors of the cruiser USS Indianapolis only hours after she had been torpedoed and sunk by a Japanese submarine south of Okinawa. In addition to pulling over 200 severely injured men from the water herself, she dropped life rafts, water, and rations to the remainder and kept station for two days over the survivors until surface ships arrived to complete the rescue. Of the approximately 700 men in the water, all but 35 were successfully rescued by Akron and other ships arriving on the scene. The airship’s machine gunners were also kept busy shooting sharks that started to appear shortly after Akron arrived.
Several days following the rescue of the Indianapolis survivors, Akron reported a surfaced submarine off Luzon This submarine was eventually attacked and sunk by aircraft from the aircraft carrier USS Essex. Postwar research in Japanese archives would indicate that the victim was I-58, which several days previously had radioed a report that it has sunk an “Idaho-class battleship”. Since no US battleship was sunk but the large and similar-looking Indianapolis was, there is little doubt Akron was both savior and executioner – a story of military fortune worth more than its weight in gold in 1960. After the war and later into his successful Presidential campaign, photos of the photogenic young airship commander directing rescue operations and shooting at sharks with a .50 cal. machine gun from a lowered cloud car virtually ensured the election of John Kennedy as the 35th President of the United States
ZRS Ships at War
In most respects, the early style ZRS-class ships (USS Akron, USS Macon, USS Wichita) were too old to be truly effective in the Battle of the Atlantic. Their airplane hangars, which had been designed around the smallest fighters available in the early 1930’s, could only handle 3 unarmed Seafin scouts, giving the ships no offensive capability other than a small number of 325 lb depth bombs carried beneath the control car.
Nonetheless, the ships did provide valuable aerial coverage for convoys crossing the Atlantic. As the war progressed and their military value declined further, they were primarily used in the long-range air/sea rescue role. Being the only craft which could loiter safely for days in U-boar-infested waters to search for and pick up survivors without needing to alight on the water, and because the ships could, if necessary, rescue nearly two hundred survivors by themselves, the ZRS ships literally saved thousands of men who otherwise may have drowned or died from hypothermia.
All three old ZRS ships were immediately retired from service upon the conclusion of the war, and scrapped shortly thereafter. The newer and more modern USS Newark was lost in a violent squall off the coast of Virginia on May 7, 1945 with all hands. USS Belleau Wood, the former Graf Zeppelin, was deflated and kept in mothballs while the Navy attempted to find a civilian buyer willing to refit her as a passenger or cargo ship. But, by this time the capabilities of airplanes had reached the point that there were no takers. She was eventually donated to the Smithsonian Institution in 1951, dismantled, and placed in storage Lakehurst Hangar No.1.
ZRCV Ships at War
US Navy wartime records claim the destruction of 34 U-boats solely by ZRCV airships or their HTA units. These documents also show that airships assisted in the sinking of another 75 submarines by surface units or conventional aircraft. Twice during the war, ZRCV ships operating alone were able to accept the surrender of damaged U-boats. On only three instances did submarines successfully attack convoys escorted by ZRCVs, and in each case, the U-boats were in turn sunk by the airship or other units operating in concert with them.
It must be acknowledged that the above destruction figures cannot be accepted at face value. Confirmations of submerged submarine kills are very difficult. Unless a submarine is forced to the surface, there is usually no clear evidence the ship has in fact been destroyed. Submarines frequently release oil slicks, clothing, small equipment and other debris as a decoy when under attack, so observation of debris cannot be taken as proof of a submarine’s destruction when it bottoms and can no longer be detected by sonar or hydrophones. Even when the submarine is in fact sunk, it is then virtually impossible to determine who actually delivered the killing blow when multiple ships or aircraft were involved.
Postwar review of surviving German records show that at least 10 U-boats reported as sunk by ZRCVs operating alone returned to their bases in France or Germany. Several other submarines claimed as “partial kills” by airships operating in concert with surface ships also made it home. Thus, it would appear that the airships probably accounted for only a small handful of U-boats claimed by allied forces in the Second World War.
However, the value of a weapons system can also be measured by its success in preventing the enemy from achieving his goals. In this regard there is no denying the effectiveness of the ZRCV airship as an anti-submarine weapon. ZRCV’s were at their best when stalking and attacking submerged submarines once contact was made. Submarines operating at or around periscope/snorkel depth could be relatively easily seen by the low flying airships. Once the target was observed, the airships could drop passive or active sonar buoys into the water while at the same time remaining effectively invisible to the submarine’s hydrophones or sonar. The airships could stay on station for up to a week in some instances and could stalk and harass submerged submarines well beyond the ability of the submarines to stay below the surface.
While there are occasions recorded in both US Navy and German records of a particularly skilled U-boat commander evading a determined ZRCV attack, these situations were few and far between. More typical is this report by KM Kapitanleutnant Heinrich Zimmer, who surrendered his damaged U-554 to the ZRCV USS Manila Bay on March 12, 1945:
"We were returning from patrol off the coast of Brazil when, at 0900, we saw two small planes heading toward us at long range. We initially believed these to be Brazilians based at Belem. I submerged to a depth of 60 meters and our ship survived several poorly aimed depth bombs, presumably dropped by the aircraft. I set a due easterly course at 6 kts and remained submerged for about 20 km. When the attacks were not repeated, I brought the ship to periscope depth and immediately observed an American zeppelin at low altitude to our SSW, approximately sixteen thousand meters distant. It appeared to be heading on a southwesterly course. Believing that the airship probably did not see us, I ordered a dive to 60 m followed by a turn to the NNE to put as much distance between ourselves and the zeppelin. We were not attacked.
"We maintained this course for approximately 100 km, at which point I surfaced the ship to replenish the batteries and take bearings. It was now 0300 on the following day and there was a full moon out. We had no trouble spotting the enemy zeppelin loitering stationary about 10 km to north of us. I maintained an easterly course on the surface, hoping that we had not been seen, but we soon came under attack by a single American attack plane we assumed was from the zeppelin. I again dove the ship, this time to 120 m. We detected several distant depth bomb explosions. By now our remaining battery power was becoming critically low. It was obvious we would not shake our pursuer, so I determined to surface and do my best to engage the zeppelin and its planes, and hopefully drive it off. We surfaced at 1000 and within minutes came under attack from three airplanes who strafed the ship with machine guns and rockets.
"We succeeded in destroying one plane and driving off the others, but all topside guns were eventually destroyed and we began taking on water. I then ordered a crash dive and emergency release of oil and decoys, hoping the Americans would believe they had sunk us. We could not bottom but ceased cavitations and maintained a stationary depth at 45 m until our oxygen virtually ran out, at which time we blew tanks and surfaced. As I feared, the enemy zeppelin was still on station. The huge ship flew right over us and dropped a few small bombs of its own, which damaged the ship’s starboard dive plane and further increased our flooding. As neither crew nor ship was in any condition to fight or flee, we signaled our desire to surrender, which the American accepted. Although I intended to scuttle U-554 once everyone was off, several armed American sailors rappelled down from the airship and took command of the bridge while the ship was still being abandoned. One German-speaking sailor let me know in no uncertain terms that his fellows on the zeppelin would murder me and my crew if the submarine was scuttled – so I didn’t even attempt it. We all knew the war was effectively over and I saw no reason to pretend otherwise. After I and all other officers were taken on board the zeppelin, and all of the crew were set adrift in life rafts, a small American prize crew took command of the ship. After about six hours an American destroyer arrived on the scene, picked up my crew and took U-554 in tow." (US Naval Archives, VIII-78c)
What Kapitanleutnant Zimmer does not report is the fact that repaired and restored, U-554 is now on display at the US Naval Airship Memorial Museum at Lakehurst Naval Air Station.
Postwar Developments
The naval airship program came close to being eliminated in the immediate years following the Second World War. The ZRS and ZRN type ships were removed from service and scrapped shortly following the end of the war, and all airship bases other than Lakehurst were closed. However, the developing Cold War gave the reduced program a temporary new lease on life.
All surviving ZRCVs were refurbished at outfitted for dedicated ASW work. Based on wartime experience, which tended to show that the hook-on aircraft had planes had minimal utility for reconnaissance or scouting, the ships’ compliment of planes was reduced to only three advanced ASW-optimized Harriers. This weight saving allowed for the ships to be fitted with a host of sonar and radar systems as well as several new and experimental missile and ASROC systems. The ZRCVs remained in service in this capacity through the mid-1960’s when they were finally supplanted by traditional escort carriers, helicopter-carrying destroyers, and frigates.
Nonetheless, both Goodyear-Zeppelin and the Navy’s lighter-than-air bureau proposed several follow-on ZRCV designs, arguing that the large rigid airship could still fill a combination of ASW and attack roles more efficiently than surface ships. As concern over the rapidly expanding Soviet submarine force increased during the 1950’s and 1960’several design studies for updated ZRCV’s were proposed. These ranged from a resurrection of the stillborn ZRCV-11 design of 1941-42, to the gigantic 18,000,000 cubic foot nuclear powered ship (ZRCVN) carrying both fixed- and rotary-winged aircraft. None of these designs ever saw fruition.
However, the large military airship was not quite dead. As a follow-on program, the Department of Defense ordered two large experimental airships which featured radical innovations such as nuclear power, advanced boundary layer control, artificial superheat to improve static lift, increased use of dynamic lift, simplified command and control systems, and other refinements. It was initially hoped these experiments would lead to a fleet of advanced early warning and air control ships, similar in concept to later AWACS aircraft. Two flying prototypes, ZRW-1 and ZMCW-1, were constructed. Rather than being operational units, they were purely flying test beds to evaluate a number of these advanced technologies in various combinations. Although their designations mirrored naval practice and they were operated for the most part by naval personnel, neither airship was a commissioned ship in the US Navy, nor was either of them named. Had they led to a series of operational units, it is believed they would probably have been operated by the US Air Force.
ZRW-1 This was the first and by far the most conservative design of the two. It featured a fairly traditional “zeppelin” structure and was completed in 1962. However, with a volume of 12,000,000 cubic feet and a length of 1015 feet ZRW-1 remains the largest airship ever built. It included a large internal bay for the AEW radar systems, communication systems, and required personnel. A second internal structure was provided near the center of the ship for a test nuclear reactor, which was fitted in 1963. The reactor was largely unshielded, protection for the crew being provided by the sheer distance (400 feet) between it and the nearest regular crew stations. The ship was equipped with a system of internal steam heating coils to provide artificial superheat to the gas cells and regulate lift. The system was also designed so that heating to each cell could be adjusted to experiment with variable heating as a means of changing attitude and trim, rather than the wasteful practice of ballast and gas release. The test reactor was used to heat the steam for the superheating system and provide electricity for the radar and communications suite, but did not power the engines. These were contained in four conventional engine cars. The ship was supplied with a single trapeze and landing station for skyhook-equipped aircraft, but did not carry its own planes.
ZMCW-1 This ship was intended to be a much more radical experiment. Her final design was not completed until after ZRW-1 had been flying so some lessons could be derived from experience with the earlier ship. ZMCW-1 was completed in 1964. Its greatest innovation was in its basic structure, which replaced the heavy and redundant zeppelin design with a stressed thin aluminum alloy skin over a very light structural framework. This system was actually quite old, having been originally utilized in the small “metal clad” naval airship ZMC-1, which operated successfully throughout the 1930’s. Although sometimes considered a “blimp”, the ZMC-1 was actually a rigid airship because its stressed skin hull could maintain its shape without internal gas pressure up to approximately 20 kts. At higher speeds, positive gas pressure within the hull was created by use of ballonets. Although the BuAer made several proposals for large ships using metal-clad principles in the 1930’s, none were pursued.
As completed, ZMCW-1 was somewhat of a hybrid, having significantly more internal structure and compartments than a pure metal-clad would. It contained slightly over 8,000,000 cubic feet of helium in six large cells, each with its own internal pressure ballonet. A separate system was used to regulate air pressure within the overall envelope. The metal hull could maintain its shape at all but the highest speeds, at which point positive pressure needed to be provided. The AEW radars were mounted within the center of the 2nd gas cell, connecting to the control gondola directly below. An unshielded nuclear reactor was placed within cell No 5, near the ship’s midsection. The reactor provided power to a steam/electric engine driving a large propeller at the stern, and to four smaller electric drive engines powering variable tilt propellers mounted along the sides of the ship. The reactor also provided gas superheat in the same manner as in ZRW-1. As opposed to all other airships, ZMCW-1 was designed to be operated in a slightly “heavy” state, with positive lift provided by the 4 large steering propellers aligned in a downward direction and/or dynamic flight provided by forward speed. In an emergency, it was calculated that sufficient neutral buoyancy would be provided by the artificial superheat. What this all meant, however, was that ZMCW-1 needed power to remain aloft, and that this power all came from a single source, the central nuclear reactor.
The other radical innovation of the ZMCW-1 involved command and control improvements, together with a concomitant reduction in crew size. The ship could be piloted by a single crewman, who controlled speed, course, and altitude from a single set of controls. Other crew stations monitored and controlled superheat, pressurization, ballast, the radar suite, and the overall operation of the nuclear plant. Thus, whereas the ZRW-1 and all other rigid airships required telegraph communications between the bridge and crew stations throughout the ship, the ZMCW-1 could be effectively flown by fewer than 10 men, all clustered together in the control gondola. ZMCW-1 was provided a single trapeze below the control car for a single plane, but like ZRW-1, it did not carry its own aircraft.
When ZMCW-1 entered flight testing in the summer of 1964, she was almost universally seen as the most sophisticated airship ever to fly. Most of her radical systems worked far better than had been anticipated, and the Department of Defense was prepared to order a series of AEW airships based on the design.
Then disaster struck. On an electronics test flight off Florida on August 12, 1965, pressure controls in ballonet No 1 at the bow of the ship malfunctioned during a routine pressure adjustment, leading to critical positive overpressure. The ship was hovered, and the problem resolved in time to avoid a disastrous explosion of the bow gas cell. However, when standard operating pressure was restored, it became apparent that the localized overpressure had compromised the structural integrity of the stressed-skin hull to the point that it could no longer maintain its shape. When an attempt was made to resume forward motion, the hull began to crumple inward, placing the internal gas cells in jeopardy. Since the ship could no longer proceed in a forward motion, the rear propeller was reversed. However, the ship was difficult to control in this direction, and it began a series of undulating altitude changes, which further stressed the damaged hull. As a result of damage to the fore gas cell and hull she was also losing helium and altitude. Finally, assisted by favorable winds as much as by her own power, the ship crossed the coast near Daytona. At this point, it was obvious a forced landing would be necessary. Her crew shut down the nuclear power plant and prepared for landfall. Drifting tail-first, ZMCW-1 glanced into the beach, ripping apart her lower fin and stern gas cell. She then slid along for almost a mile, and finally came to rest, her hull ripped apart and crumpled into an almost unrecognizable shape. The ship was a total loss. Out of the twelve men on board, all survived. Luckily, as designed, the reactor capsule remained intact. In some respects, even this disaster proved the advantages of some of ZMCW-1’s design concepts. The self-contained control gondola with its small crew probably helped save lives and all safety mechanisms associated with the nuclear reactor worked flawlessly. However, none of this made up for images of a multi-million dollar airship crumpled on the Florida coast like a rotten, beached silver whale.
Following the loss of ZMCW-1, the Department of Defense lost all interest in pursing similarly designed airships – and for all intents and purposes – airships in general. The remaining ZRCVs had already been retired and ZRW-1 (with its nuclear power plant and AEW systems removed) was offered for sale to private bidders. But by 1965, there had not been a commercial airship in service in 20 years, and there were no takers. The ship was scrapped in March, 1966.
The Final Acts
All of the retired ZRCVs were finally scrapped during in 1969, except for USS Bon Homme Richard, which was transferred to the United States Coast Guard, who operated her intermittently in the air/sea search and rescue role for two years. Her ASW equipment was removed and she carried 3Super Goose flying boats. She was never formally commissioned as a ship in the Coast Guard, and was only referred to by her Coast Guard designation CGZ-1. In this guise, she was painted in the traditional white Coast Guard livery, with the diagonal red stripe and Coast Guard insignia on her forward hull. She was never particularly popular with “front line” Coast Guard stations, who considered her a fair weather craft forced on the service by the Department of Defense and Navy Reserve. She spent most of her time on public relations and recruiting tours on the Atlantic and Gulf Coast. She was finally retired and scrapped in 1972.
Although the last rigid airship flew in 1971, the Belleau Wood/Graf Zeppelin still survived as a partially dismantled structure occupying space in the old Hangar No. 1 at the Lakehurst Naval Air Station. In 1980, after a survey of the ship’s rings and longitudinal girders showed the hull retained enough integrity to permit eventual reconstruction, the airship’s framework and Hangar No. 1 were placed on the National Register of Historic Places as unique technological reminders of the rigid airship era. Popular interest in preserving the airship was further stimulated by several Navy proposals in the late 1980’s and early 1990’s to demolish the hangar at Lakehurst (and by implication the airship framework) to make way for training facilities.
As early as 1976, airship enthusiasts on both sides of the Atlantic had already been lobbying for her reconstruction and preservation as a museum ship, and the threats of demolition gave them further ammunition. Several lawsuits and injunctions in the 1990’s prevented demolition of the hangar and the airship’s structure. In 1995, the German government entered the controversy and became an active advocate for the airship’s preservation. Finally, on November 3, 1998, President Clinton and Chancellor Helmut Schroeder signed an agreement in Washington pledging their respective governments to preserve the zeppelin, and share equally in the funding of a project to reconstruct it for static display, should a suitable location be found.
Today, together with the reconstructed and relocated Lakehurst Hanger No 1, the 803 foot-long airship is the centerpiece of the huge Lighter than Air Exhibit at the Smithsonian’s National Air and Space Museum (NASM) Annex at Dulles International Airport. As requested by the German government, the ship has been reconstructed inside and out as the civil Graf Zeppelin. At Germany’s insistence, she does not sport huge swastika flags on her fins. Many people, such as various Jewish-American and human rights groups, supported this. However NASM staff and others in the preservation community strongly advocated for the swastikas as necessary to present the ship in an historically accurate context. For a while, it appeared that this controversy could even derail the whole restoration project. Eventually, however, a compromise was reached eliminating the Nazi flags from the ship, but allowing accurate Nazi emblems on all photographs, travel posters, brochures, tableware, crew uniforms, and other small items accompanying the airship’s exhibit, providing that no replica items offered for sale in the museum’s gift shops contained swastikas or other Nazi emblems.
Graf Zeppelin’s gas cells are occasionally inflated with an inert mixture of nitrogen and helium to check for rips and tears in the goldbeaters’ skin, but normally the airship is maintained in a non-inflated state. She hangs beside a 1/10 cutaway scale model (still almost 100 feet long) depicting her in her wartime US Navy guise. Several restored hook-on aircraft ranging from one of USS Akron’s original F9C Sparrowhawks to a post-war ASW Harrier are also part of the exhibit. All internal passenger spaces have been painstakingly replicated as they would have appeared in 1939. Open for public tours during the museum’s regular hours, and also available for special events and dinners, she is the single most popular exhibit in the entire Smithsonian collection.
From time to time, representatives in Congress or the German Bundestag put forward resolutions that the airship be refitted for flight. Following standard NASM practice, the restoration of her engines, control systems, and structure was sufficiently thorough that she probably could be flown with minimal additional work.
However, this is strongly rejected by historic preservationists and aviation safety experts on both sides of the Atlantic. In the airship’s current restored condition, she completely lacks modern avionics and safety systems required for FAA approval, and the installation of such equipment would impair her historic integrity as a museum exhibit. Even if she could be flown, there are no longer enough people still alive with the training to safely operate her in the air or handle her on the ground, making any attempt to fly her incredibly risky.
Times have changed. Technologies have changed. It is remotely possible that Graf Zeppelin could be inflated with full helium during a routine gas cell check and allowed to “float” at neutral buoyancy in within its display hangar, but she will never ply the open skies again. Nor will any other zeppelin airship.
The US Civil Airship Program – Missed Opportunities and Bad Timing
Any history of the successful US Naval Airship Program is incomplete without at least some discussion of the parallel civilian program undertaken by the United States in the 1930’s. As has been noted, by the mid-1920’s the United States was well-placed to take the lead in the civil application of airship technology. The US had the world’s only commercially extractable sources of non-flammable helium lifting gas. Goodyear’s 1923 joint venture with the Zeppelin Company gave the nascent US airship industry access to all the knowledge, technical expertise, and patents of the acknowledged German experts in the field. The 1928 Airship Act gave the rigid airship favored status in US overseas commerce, and subsequent amendments together with generous WPA funding in the 1930’s provided ample money to support the construction of commercial airships, airship hangars, and other support industries.
Initially, the Goodyear-Zeppelin airline venture looked like a success. Two separate US flag carriers were chartered in 1930: the American Zeppelin Transport Company (AZTC) to handle international flights to Canada and Latin America, and the Pacific Zeppelin Transport Company (PZTC) to link the continental USA with Hawaii, Australia, and the Far East. Through the auspices of the Goodyear-Zeppelin partnership, the US routes were merged with those flown by the first Graf Zeppelin (LZ-127) between Europe, North America, and South America to create a globe-spanning network. In 1931, the operations of the US and German airline operations were combined, and the old Graf spent one year assigned to the PZTC, carrying paying passengers while pioneering commercial routes from Sunnyvale NAS to Tokyo, Manila, and Sydney.
In 1930, LZ-128 was laid down by the Zeppelin Company in Friedrichshafen specifically for use by Zeppelin’s American partners. With a gas volume of slightly over 7,000,000 cubic feet, she was a slightly smaller prototype of the later LZ-129 Hindenburg, with an internal passenger bay, individual staterooms, and public areas capable of handling up to 55 passengers and freight. In 1932, her maiden voyage took her to Akron, Ohio, where she was commissioned ZS Spirit of America and entered service on PZTC’s California-Hawaii route. In 1931, Goodyear-Zeppelin ordered its first three US-built civil airships, based closely on the firm’s parallel ZRS-4 design (USS Akron). Late in these ships’ design, an extra bay was added, making them slightly larger than Spirit of America.
The first American ship, ZS Columbia, was completed in early 1934, and her sister, ZS Pacific Star, took to the air later that year. As detailed elsewhere, completion of the third ship of the class was delayed by labor stoppages, and when she emerged in 1937, it was as the navy’s ZRS-6, USS Wichita.
ZS Columbia was initially employed on AZTC’s South American route, and ZS Pacific Star, as her name implies, was used solely on extended routes linking Hawaii to Manila, Tokyo, and Sydney. Although both ships never lacked for paying passengers, they were never wholly satisfactory as passenger liners. Following standard late 1930’s practice, passenger spaces were housed in the hull, occupying areas that would have been devoted to airplane hangars in military versions of the design. Double berth interior cabins were provided for up to 45 passengers, with surprisingly small and Spartan public areas on either side serving as lounge/dining rooms.
A major problem was the interior location of the ships’ eight engine rooms – a trait inherited from the basic ZRS design. When operating at full power, these engines imparted noticeable vibration to the passenger areas, and were also noisier than the exterior power cars used on German zeppelins. Passengers who had the opportunity to travel on German ships such as Hindenburg invariably commented on how less comfortable and less luxurious the American liners were.
Goodyear-Zeppelin soon recognized these faults, and the next series of three commercial ships laid down in 1935 were in many ways enlarged versions of the Zeppelin Company’s sucessful Hindenburg design. The ships reverted to standard zeppelin design practice with a strong lower keel and four exterior power cars. They also reverted to even older zeppelin practice by placing first-class passenger cabins in an elongated external control car, giving these passengers an outstanding exterior view from their cabins. As designed, they would have contained over almost 10,000,000 cubic feet of helium, making them in size, if not detail design, the commercial equivalents of the naval ZRCV ships. They would have been named after US Presidents: ZS George Washington, ZS Abraham Lincoln, and ZS Theodore Roosevelt. None of these ships were completed, however, first falling victim to the gradual demise of the Goodyear-Zeppelin partnership, and finally to the Second World War. Goodyear briefly sought to resurrect these designs in the late 1940’s, but by then the era of commercial passenger zeppelins had passed.
By late 1935 diplomatic relations between the United States and Hitler’s Germany were becoming strained. Although the Goodyear-Zeppelin partnership still existed on paper, the operation of the joint airline service was disbanded when the Nazi government nationalized the Zeppelin Company’s airline operations under the Deutsche Zeppelin Reederei. In the US, the original Graf Zeppelin and the new Hindenburg became increasingly visible symbols of the unpopular Nazi regime, emblazoned as they were with gigantic Nazi flags. Increasingly, Goodyear’s association with the German airship industry made the firm unpopular among many Americans concerned about the direction in which the Nazis appeared to be leading Germany and the world. This reached its low point during the strike of 1937, when Goodyear’s tires were routinely referred to as “Hitler Doughnuts” by labor representatives.
However, the final dissolution of Goodyear-Zeppelin’s commercial venture came from Germany itself. The Zeppelin Company’s Director, Hugo Eckener, a long-time opponent of the Nazi movement, was eventually pushed out of his positions at both Zeppelin and the Deutsch Zeppelin Reederei in 1937 by the Nazi Party. While the full details of what then transpired may never be known, it would appear he and several others in the Zeppelin organization hatched a scheme to commandeer the Hindenburg while en route to the USA during its initial crossing of 1938 and either defect with the ship to the USA, or failing that, destroy it as part of a highly visible anti-Nazi protest while on American soil. What is known is that the Hindenburg did turn back to Germany while over the Atlantic, the only time a commercial zeppelin never completed a regularly scheduled crossing in 12 years of operation. It is also known that Eckener and 13 other Zeppelin employees were immediately arrested upon their return to Germany and imprisoned at Dachau on May 6, 1938. All but one of the conspirators, including Dr. Eckener, eventually died in the concentration camp.
Not unexpectedly, the Nazis accused the US of complicity in this plot, claiming that several US naval officers and Goodyear-Zeppelin employees attached to the Lakehurst Air Dock knew of Eckener’s plans. In retaliation, the Nazi government liquidated the Goodyear-Zeppelin partnership in Germany and suspended all zeppelin flights to the USA for the remainder of the 1938 season. Ironically, when transatlantic flights were resumed by Hindenburg, the new LZ-130 Graf Zeppelin, and LZ-131 Deutschland in 1939, the new Graf Zeppelin found itself in the USA at the outbreak of the European War, and, as related elsewhere in this paper, was interned and in 1940 sold to the US Navy in a short-lived wartime propaganda coup for the Nazi government.
Also, throughout the 1930’s the capabilities of airplanes increased significantly to the point that, by 1939, several of Boeing’s new Clipper Ship flying boats could provide better and more flexible commercial capabilities in trans-Atlantic and trans-Pacific travel than the two PZTC airships, ZS Spirit of America and ZS Pacific Star. This was even truer for AZTC’s ZS Columbia’s route through the Caribbean to Brazil. When 1940 diplomatic difficulties with Japan closed the Tokyo route, this also led to the abandonment of the Manila and Sydney runs, which by themselves were insufficiently lucrative to support regularly scheduled passenger service. In early 1941, both the PZTC and AZTC were reoriented as charter lines, with their airships increasingly used to transport bulk freight and military personnel rather than civilian passengers. Spirit of America was relegated to occasional marketing flights and special cruises along the Pacific coast.
With the outbreak of the Pacific War, all three ships were commandeered by the Navy and used to haul high volume cargo and key personnel to Hawaii. Spirit of America was damaged in a mooring accident at Sunnyvale in August, 1942, and sold for scrap later that year. Columbia and Pacific Star continued in service until early 1944, when they were also scrapped to make room for aircraft maintenance facilities in their California hangars. The retired, original, LZ-127 Graf Zeppelin, together with the Deutschland and Hindenburg, met a similar fate in Germany, marking an ignominious end to what started out as a grand experiment in international cooperation and luxurious aviation travel.
Every so often there are those who push for the resurrection of zeppelin airships as luxury aerial cruise ships for the rich or specialized heavy-lift vehicles. As much as these plans sound attractive to the general public, especially those who remember the exploits of the US Navy’s wartime zeppelins or the luxurious German civilian liners, they eventually run aground when looked at in the harsh light of economic reality. Luckily, we do have one surviving airship, and anyone who wishes can experience what airship travel was like for free by visiting the delightful Graf Zeppelin exhibit at NASM.
Auxiliary and Support Vessels
A number of proposals were made in the immediate prewar years for support vessels capable of tending and basing ZRS and ZRCV type airships on remote stations. Although there had been some early airship landing experiments with the carriers USS Saratoga and USS Ranger, and several fleet oilers had been provided a high masts to serve as experimental airship tenders in the 1920-1940 period, these did not provide a satisfactory solution. The only feasible early option was to erect temporary masts at advance bases. Such masts were widely used, but the airship was completely open to the effects of atmospheric cooling, solar heating, wind gusts, and other weather events. Because this required the airship’s crew to constantly monitor and adjust to changing conditions, stationing ships at temporary facilities for more than a few days was discouraged. Only hangars provided the security necessary to base airships for an extended period.
With the outbreak of the Second World War, most large airship hangar facilities overseas were either occupied by Axis powers or within easy range of enemy land-based or naval aviation. Further, the ZRCV ships were so large that they could not be permanently stationed at any land-based airdock other than those built for this purpose in the continental United States.
In 1942, BuAer offered several proposals for large sea-based platforms capable of servicing and sheltering large rigid airships. Three alternative design schemes were proposed and studied.
The most simple solution was not actually a vessel, but comprised a hangar facility erected on a series of massive floating platforms, not unlike the pontoons used by army engineers to erect temporary bridges. Rather than sailing to the remote bay or cove, the hangar would be assembled there. This was by far the least expensive approach, but had no other advantages. Complete maintenance of airships would still have required substantial land-based facilities. The concept was rejected by the Navy outright.
The Auxiliary Airship Dock proposal (AZD) envisaged a large, unpowered barge-like vessel that would be towed and anchored in its intended location. The AZD was far superior to the pontoon design because it offered useful hull space to contain all supplies and materials necessary to maintain an airship and its aircraft on remote station. However, the Navy perceived that towing a massive barge hangar over 1000 feet long across several thousand miles of open sea had many obvious and potential risks. In addition, while the AZD could service and maintain its airship, it would require its own tenders and tugs to maneuver, and these ships would need their own support facilities. The AZD concept was therefore rejected.
The preferred approach was a self-propelled Airship Tender (AZ). This was a massive self-contained ship featuring a large hangar and mooring out mast occupying over 90% of its overall length. The hangar design itself was very complex, featuring retractable top and collapsible sides. In its massive hull, the AZ carried all that was required to service, repair, and maintain one ZRCV-type airship in addition to machinery and fuel sufficient to steam a one-way distance of 4000 miles at 20 kts. The AZ would be provided with maneuvering screws so it could be rotated to eliminate or minimize crosswinds during mooring operations.
All this required a huge ship, with a far greater displacement, length and beam than an Iowa-class battleship or Midway-class aircraft carrier. Although this design was selected as preferred option, and final designs were developed, the Navy was no position during the Second World War to consider building such gigantic and extremely costly auxiliaries that had no combat capability and could not even transit the Panama Canal. The AZ concept was briefly resurrected in the 1950’s as the Navy assumed a more permanent global presence during the Cold War. New design studies were done, but the decision to retire all the ZRCV’s in 1964 ended any further consideration of a dedicated airship tender in the fleet.
In retrospect, the AZ was a vessel devoid of a real purpose. The Navy never gave any serious consideration to permanently basing airships outside of the US, nor did leadership ever look favorably on making a major investment in huge ships solely dedicated to servicing the relative handful of large airships in service at any one time. Even during their heyday in 1942-45, the ZRCV ships were considered a luxury – a useful luxury, but not a necessary one. The following 1943 congressional testimony from Admiral Ernest J. King regarding the AZ tender sums up the situation well:
“The ZRCV airships we currently have on hand are proving to be extremely useful against the German u-boats. I was always a proponent of these ships and am glad we have them now. However, I do not see us building any more. Regarding the airship tenders you asked about, such vessels would represent a dangerous diversion of resources from what the Navy really needs: more effective combat ships, fleet oilers, and airplanes. Building only one AZ would eliminate one large carrier, three escort carriers or as many as fifteen destroyer escorts from our building program. We need those ships. We do not need the AZ.”
Experiments and Alternate Missions 1939-1944
In addition to their acknowledged ASW role, a number of other uses for rigid airships were proposed and investigated immediately before and during the Second World War. Although basic technological limitations of the airship or military developments eventually rendered these concepts impracticable, they are interesting footnotes in the history of this unusual weapon system.
Stand-off Strategic Bombing As early as 1938, anticipating the possibility that the United States might become involved in a war against Nazi Germany without allies and land bases in Europe or the British Isles, the US Army Air Corps evinced some interest in adapting large ZRCV-type airships as stand-off carriers for their multi-engined bombers. The scheme was strongly opposed by the Navy, who did not want the USAAC intruding into a technology they saw as uniquely naval. However, the Army Air Corps saw this as an interim method of mounting long range or transatlantic bombing missions pending eventual development of planes such as the B-29, B-32, B-35, and B-36. In 1940, when the fall of Britain seemed likely, the Air Corps commissioned a design study from Goodyear-Zeppelin for a 15,000,000 cubic-foot airship capable of carrying, launching and retrieving up to four Boeing B-17D heavy bombers in flight or up to six North American NA-42B (B-25) medium bombers. Goodyear’s calculations showed that operation of four-engine heavy bombers from zeppelin trapeze systems would create unacceptable stresses on the airship’s keel and main frames. However, stripped-down versions of smaller twin-engine bombers such as the B-25 or Douglas DB-7 (A-20) could be modified to operate from airships with minimal penalty. As opposed to the standard ZRCV practice, the airship would lift off empty, the fully fueled and bombed up aircraft then flying to the airships and hooking on for the transatlantic flight. When carrying the aircraft, the airship would fly “heavy”, dependent in part on aerodynamic lift provide by its forward speed and a slight nose-up attitude. The airship would launch its stand-off attack when the intended target was within the bombers’ radius of action (roughly 600-1,000 miles). Just prior to the cancellation of this scheme in 1942, a proposal was floated by the Army to use de Havilland Mosquitoes in the hook-on role. As events proceeded there never was any need to further explore the concept of airships as stand-off strategic bombers. Had the plan been pursued, other problems would almost certainly have been encountered attempting to mate such large, high-performance, heavily loaded, multi-engined craft to the lightly constructed and relatively slow airships.
High Speed/Heavy Lift Transport The relatively short-lived effectiveness of GZ commercial airships as high-speed heavy haulers between the West Coast and Hawaii in 1941/1942, led to a proposal to refit the obsolescent ZRS-class airships (Akron, Macon, Newark, Wichita, as well as the former Graf Zeppelin, as high-speed, long-distance transports for critical equipment and bulk cargo to US bases throughout the western Pacific. The onboard aircraft hangar and aircraft service spaces would be converted to cargo space and all military equipment and stores would be eliminated. However, it was determined that large floatplanes such as the Martin Mars and Hughes-Kaiser HK-1, as well as several large multi-engine landplanes under development for the USAAF, would soon be able to fulfill most of the heavy transport roles planned for the airships, so the scheme was dropped.
Key Personnel Transport. In 1941, the Navy Department seriously considered refitting ZRN-3 Bismarck (the former Graf Zeppelin) as a dedicated long-distance transport for the President, White House staff, or other key civilian and military personnel. The former passenger spaces would be restored, but reconfigured into an efficient combination of offices/conference rooms, communication facilities, and private sleeping quarters. Plans called for the retention of three “perches” for emergency fighter escorts and a courier plane. However, the Roosevelt White House was not keen on the plan, and it was soon realized that the concept would result in a compromise: a craft lacking the speed of traditional transport aircraft such as the C-47 or C-54 or the security and comfort of escorted commercial liners or warships. A plan and cutaway scale model of this proposal can be seen in the Smithsonian’s Lighter-than-Air Exhibit at Dulles International Airport.
Airship HTA Units
With the expansion of the naval airship comand, it became apparent that new aircraft designs needed to be developed for use on airships – designs which explored a variety of fixed or semi-retractable skyhook systems and saved weight by making use of very light construction and elimination of conventional retractable landing gear.
A very low stalling speed was also essential, since, while being retrieved, the aircraft had to maintain excellent controllability while matching the 70-80 kt maximum airspeed of the airship. Because of these limitations, only a few operational airship aircraft were direct modifications of existing carrier- or land based types. Rather, most were designed by the Navy’s BuAer and manufactured to these specifications by Grumman, Douglas, Brewster, Curtiss, or other contractors. Three general types of aircraft were developed for airship service: reconnaissance planes/fighters, “running boats”, and bombers. Key types are described below:
OZC Seafin This was a single seat high-wing reconnaissance type with fixed skyhook. It was heavily modified nu BuAer from an original Curtiss design for a fighter or advanced fighter trainer. Somewhat optimistically the OZC was also rated as a light fighter and provided with one synchronized .30 cal machine gun. The type had a combat radius 200 miles on internal fuel, 300 with auxiliary fuel tank. It served as a standard observation or reconnaissance plane on all airships 1939-1945, although by 1942 it only served on the ZRS-class ships. Like most airship types it had no conventional landing gear.
F3A Shrike This was a single seat, single engine low-wing monoplane based broadly on the Vought-143 fighter and adapted for airship use by Brewster. It was armed with two .synchronized .03 cal. machine guns and could manage a 150 mile radius on internal fuel. A fixed skyhook was mounted above the cockpit. Although the plane was provided with a retractable landing gear, these and the mechanism necessary to operate them were usually removed by airship crews to save weight. Simple stick landing gear could be fitted for conventional landings and takeoffs when necessary. Relatively few built were and they were rarely carried by airships operating in the Atlantic.
SBZD Attacker This was a one or two seat attack plane. It was designed by BuAer as a slightly smaller and much more lightly constructed version of the Douglas SBD Dauntless. The SBZD was not fitted with conventional landing gear and had a fixed skyhook. As originally designed, it was a single place attacker capable of carrying two depth bombs or three 250 lb bombs and armed with two fixed forward-firing .30 cal machine guns. Many Attackers were subsequently modified in service to carry an observer/gunner in a rear extension of the cockpit with a single defensive .30 cal machine gun. The SBZD was the navy’s standard airship-borne reconnaissance bomber 1941-1943. Most were built by Douglas.
PBZF Harrier The Harrier was without question the most versatile and capable ZRCV-based aircraft to se operational service. It was a small, twin engine ASW floatplane similar in concept to the Grumman Goose. Alone among airship-based aircraft the Harrier was designed for two occupants. It was capable of carrying up to 4 depth bombs, surface search radar, active/passive sonar buoys, and late in the war, two homing torpedoes. The plave had a 200 mile combat radius and was equipped with a semi-retractable skyhook in a pod on upper wing surface. With a wingspan of 49 feet, the PBZF was the largest aircraft routinely carried by the ZRCV ships, and its floatplane configuration promoted its aggressive use at sea, even though it lacked any defensive armament.
NZV Mule This was a twin engine “running boat” capable of carrying up to 6 passengers, supplies, and fuel for in flight servicing of the airship or its aviation unit. It was somewhat similar in appearance to the Lockheed Ventura but considerably smaller Due to their size and weight, Mules were never embarked on airships – rather they were used for supply and transferring personnel from ground bases or conventional aircraft carriers.
Other Types From time to time other aircraft were provided with temporary skyhooks and operated experimentally from the navy’s airships. Among these were Sea Hurricanes, F4F Wildcats, Fairey Swordfish, and Westland Lysanders.
Complement Mix Depending on the area of operations and the airship’s planned mission, the operational complement of aircraft embarked would vary. Early in the war, ZRCVs usually carried 4 Shrikes and 6 Attackers, or 5 Shrikes and 3 Harriers on convoy escort or patrol missions. Later, as the airships were used more as independent ASW platforms, the ZRCV aircraft compliment was often reduced to as few as 3 Harriers. This allowed the ships to carry a much heavier offensive payload of ordinance for themselves and their its aircraft. When operating independently against U-boats in the western Atlantic, individual ZRCVs often operated in tandem with a ZRS, the ZRS using its Seafin scouts to increase the team’s chance of locating surface submarines and the ZRCV using its Harriers to attack it.
US Naval Airship Nomenclature
As opposed to the British and Germans, who in World War 1 only assigned their rigic airships numbers, the US Navy assigned them both numbers and names in the same manner as surface combatants.
All airship numbers began with a letter prefix beginning with “Z” (which indicated “airship”, not “zeppelin” as commonly supposed), followed by additional letters indicating the ships’ type and function, finally followed by the ship’s unique fleet number indicating its sequence among commissioned naval airships of its type. Thus, “ZN” indicated “airship, non-rigid”, “ZR” indicated “airship, rigid”, “ZRS” indicated “airship, rigid, scout”, “ZRCV” meant “airship, rigid, aircraft carrier”, and so forth.
Other than the ZR-1, which was given the name USS Shenandoah, “Daughter of the Stars”, and the ZR-2, which was lost before being formally commissioned into the navy, the early rigid airships all were named after US cities: (USS Los Angeles, USS Akron, USS Macon, etc). This reflected less any set system at the time as it did a desire to cater to powerful and influential political supporters of the airship program. However, it did appear to have a certain logic, because most naval officers considered the large airships the airborne equivalents of scout cruisers, which were also named after cities.
With the eventual acceptance of rigid airships as regular fleet units – and especially the introduction of the ZRCV classes which were seen as more equivalent to light aircraft carriers than cruisers, the Navy felt the need to decide on a systematic nomenclature for the navy’s growing fleet of rigid airships. Initially BuAer proposed an entirely new system involving birds of prey or nautical weather events, both of which would have promised exciting and evocative nomenclature. However, since it already had five ships named for cities, the Navy decided to retain the use of city names for the new ZRCVs and ZRNs but also add famous historic American naval vessels or battles (which were also used for aircraft carriers) as potential name sources for the ZRCV airships.
US Airship Colors and Markings, 1922-1971
Military Airships
Color Schemes. In the interwar years, the fabric exterior of all US airships was covered with several layers of clear dope, followed by a silvery aluminum exterior coat. It was popularly believed that this was mainly for aesthetic purposes. Actually, reflective silvery dope was used to minimize solar heating of the lifting gas, which was important in maintaining predictable lift and trim. Beginning in 1940, as US entry into the war became increasingly likely, the Navy experimented with several alternative doping/painting camouflage schemes for large airships, the most radical being a disruptive pattern of white, black, silver, and light blue applied to USS Wichita.
Eventually in early 1942, the Navy settled on a standard two tone silver and grey “camouflage”. This scheme retained the reflective silver doping on the upper third of the airship, with the lower 2/3rds a very light non-reflective grey, essentially similar to US Navy measure 5-L Light Grey. It is questionable how effective any camouflage scheme was; no matter what color, a 900-foot long rigid airship operating between 2000 and 4000 feet above the sea is a hard thing to hide. After the conclusion of the war, all surviving ships reverted to overall silvery dope.
Markings and insignia. Prior to 1939 airships carried large national aircraft insignia on the lower hull immediately in front of the control car, and one on each side of the hull in front of the horizontal fins. The ship’s name (e.g. “Akron”) was painted in small letters directly in front of and just below the horizontal fins, on both sides. The airships sported a very large “U.S. Navy” (or in some case just “Navy”) on both sides of the ship near the midsection. They did not display any other identifying numbers. Rudder and elevator surfaces were painted in a vertical blue-white-red scheme. For a very brief period training airships (Los Angeles and the two ZRNs) had their horizontal and vertical fins painted high visibility yellow
With the outbreak of the European War in 1939, additional “neutrality” markings were added to US naval airships. These included large US flags painted on both sides of the hull above the control car, and a fourth national insignia on top of the ship. These were added to help ensure that US airships engaged in intelligence-gathering and training flights in the eastern Atlantic were not confused with surviving German passenger zeppelins and attacked by British or French aircraft. This precaution was almost certainly an over-reaction, given the fact that, after September 1, 1939, German commercial airships were operated only on a limited basis in Central Europe, and were grounded altogether after June, 1940.
In this context, however, it is interesting to note that for a brief time in late 1940, the Abwehr considered a scheme to refit and repaint Hindenburg as a virtual copy of the US Navy's USS Belleau Wood/Graf Zeppelin, provide her with a number of English-speaking Luftwaffe officers, and use her for intelligence gathering and reconnaissance for surface and subsurface commerce raiders in the Atlantic. The presumption was that the Allies would be reluctant to attack what appeared to be an American naval airship, making the Hindenburg almost immune while it carried out its missions. Thus, had this scheme found favor, there would have been a very real risk that US naval airships could have been operating in the general vicinity of German airships
After 1941, when it became obvious that US airships could never be confused with vessels of any other power, airplane-style national markings were reduced or eliminated. The vertical tricolor stripes on the rudders and elevators were eliminated and both lateral national insignia and the large “U.S. Navy” were removed. A single, small, national insignia was retained in front of the control car, more for morale reasons than any other, since it was barely larger than the roundels applied to regular aircraft and would be essentially useless for national identification at the ranges airships were readily visible to friend or foe. The style of this roundel underwent the same revisions as other US aircraft insignia, until the final blue and white “star and bar” was adopted. The small airship’s name on both sides of the aft hull was retained.
As “ships” that also flew, the Navy’s rigid airships had always occupied a halfway house between being considered aircraft and surface ships. In nomenclature they were treated as commissioned ships but were also given airplane-style roundels. Finally, in late 1944, the Department of the Navy determined, once and for all, that rigid airships were to be treated as fleet units, not aircraft. As a result, the small aircraft roundel in front of the control car was permanently eliminated, and in place of this each ship could paint a small official ship’s shield.
Throughout the war, a number of officially sanctioned and unsanctioned markings were also employed to enhance crew morale. This included officially sanctioned “victory” symbols painted on the control car, usually stars or submarine silhouettes, to denote successful missions, and campaign/battle ribbons that were awarded to the whole ships’ company, also displayed on the control car. Unofficial personal markings (slogans, pictures, etc) were also frequently painted on engine cars and gun stations by individual crewmember or watches.
After the war, the large “U.S. Navy” reappeared on both sites of the hull, and the ship’s name near the fins was enlarged slightly. Other than small battle and campaign ribbons, shown on the control car, all other wartime markings were eliminated.
Incidentally, all US Navy rigid airships were provided with naval ensigns and jacks, as well as a standard set of signal flags that could be raised (lowered actually) from the control car on weighted landing lines if radio or semaphore communication was impossible. Flags were rarely flown unless the ship was operating at less than 45kts. Only the national ensign was routinely flown, this from a special collapsible staff just aft of the lower fin.
The HTA Unit. The system of markings and national insignia on airships’ planes generally mirrored those used by other shipboard naval aircraft. One major difference was the general absence of standard Navy camouflage schemes. To minimize unnecessary weight, airship-borne planes were usually left with unpainted natural metal or doped fabric surfaces. On the other hand, because airship aviators considered themselves the elite pilots of the Navy, their planes sported a much wider array of brightly colored personal art than typical for the Navy, often featuring variations of the “trapeze artist” squadron markings first employed by the HTA unit assigned in 1934 to USS Macon. Because of their unpainted metal and colorful nose art, HTA units often looked more like they should be in the Army Air Corps, not the USN. Because of this, and as a result of natural rivalry with the airship aviators, other naval aviators often referred to their HTA unit colleagues as “The Army Clown Corps”
Civil Airships
Airships operated by Goodyear-Zeppelin’s AZTC and PZTC airlines sported a relatively simple livery, consisting of an overall aluminum doped hull with a 10 foot wide painted stripe extending the full length of the ship on each side of the hull. AZTC ships sported a blue stripe, while that used by the PZTC was red. US flags were painted on the upper and lower fins. Each ship’s name was painted in a cursive script immediately below the stripe, above the control car on the ship’s starboard side, while the full airline name was rendered in script on the port side. During the Second World War, when all civilian ships were taken over by the Navy for high speed bulk transport, all markings except the US Flags on the fins were removed. Since they were operated as civilian adjuncts, not regular naval units, they did not receive any naval markings, and retained their overall civil aluminum doping.
Appendix A. Reproduction of December 1942 Signal article allegedly authored by KM Kapitanleutnent Klaus Handel of the U-367.
We Destroy an Enemy Zeppelin
In this day of modern warfare the submariner sees many new and wonderful things. They see our U-boats deliver sudden destruction to the enemy while safely hidden under the sea. They see our powerful battleships and cruisers attack his convoys. They see Stukas deliver deadly bombs on the decks of his warships. They see long-ranged flying boats and Condor bombers magically find and destroy fat troopships, and they read about the naval forces of our Japanese allies delivering complete destruction to the American and British navies in the Pacific.
Thus, it is not surprising that we see the United States and Britain using increasingly desperate measures to combat our submariners in the Battle of the Atlantic. Informed Signal readers will remember that in 1939 the German Reich sold the zeppelin passenger airship LZ-130 to the United States as a goodwill gesture to the American people. Now, it seems that the US Navy has become so desperate in its attempt to defeat our U-boats that it has resorted to flying the LZ130 and fragile craft like it far out to sea to as escorts for troopships and transports headed to England. The report below by Kapitanleutnent Klaus Handel of the U-boat U-367 is a first-hand account of what actually happens when such relics from the First World War meet up with a modern ship of the German U-boat service and its well-trained crew.
“We had just completed a very successful mission off the eastern coast of the US and were heading home on the surface to celebrate when we first saw the enemy zeppelin floating at low altitude about 15,000 meters off our port bow. It appears the American commander saw us at about the same time because the airship turned and began heading straight for us. Although the zeppelin was almost 15 kilometers distant and hard to see in the low sun, I was able to discern through my binoculars that it launched two or three small airplanes (it may come as a surprise to most Signal readers, but the American navy is known to hook small attack planes on the LZ-130 and other zeppelins). As the planes neared us, I ordered an emergency dive to 60 meters. The American pilots released their bombs well behind us - we could hear the explosions as muffled crumps on the hydrophones. Several minutes later, we heard a second series of explosions, this time considerably closer to us.
“For over 36 hours, we played “cat-and mouse” with the enemy airship and its airplanes, rising to periscope depth or briefly surfacing to get our bearings and then submerging to easily avoid the inevitable air attack which followed. Unfortunately, the enemy seemed quite determined to follow us all the way to France and our batteries (necessary for travel under the sea) were becoming drained. I was also concerned that the enemy would call a more capable opponent (such as a destroyer) to assist in our pursuit.
“Thus, I determined to battle the airship using one of the oldest weapons in the warrior’s bag of tricks – deception. After the sixth ineffective air attack by the zeppelin, I ordered all of our decoys released and surfaced the boat as if in emergency. Immediately upon reaching the surface, we engaged the diesels and ran extra oil through them, exhausting clouds of dense, black smoke through the conning tower and all other vents. We were very fortunate because favorable breezes blew the smoky haze over ship’s conning tower and deck, hiding my crew as they manned the guns and spotting stations. Through the smoke we could see the American airplanes hooking on to the zeppelin, which was still several kilometers distant. One can only imagine how helpless we appeared to the enemy! A stationary submarine wallowing amidst smears of oil and debris and issuing dense black smoke from all open ports! To assist in the ruse, I ordered several crewmen to inflate life rafts and take to the sea as if abandoning ship.
“After a few minutes, the American zeppelin turned and headed straight for us. Apparently its commander had taken the bait and decided we were so helpless that he could use his fragile gasbag itself to deliver what he must have believed would be the final blow. I ordered the gun crews to aim for the small control car near the giant airship’s bow and hold their fire until I gave the order to engage.
“Finally, when the nose of the zeppelin was so close we could make out the faces on the enemy airmen in the control gondola, I gave the order. Our well-trained gunners scored immediate hits on the gondola, tearing it to pieces and ripping huge gashes in the fabric hull above it. Apparently this blow killed or crippled the American commander and other officers, because the zeppelin floated right over us without dropping any bombs. Our machine gunners then peppered its soft bottom as it flew overhead, and I could see small fires starting through rips in the hull fabric. Initially, we all thought the huge ship would explode in a ball of fire like the zeppelins of yore, but then I remembered that the Americans used non-flammable helium in their airships.
“After passing over us, the enemy began a slow turn to starboard and I ordered the gun crews to fire on the two large engine cars extending from the side of the ship. Again the range was very close, and we scored immediate hits. Our main 88mm deck cannon destroyed the starboard aft engine car with a single well-placed high explosive round, while the other engine was disabled by repeated light cannon and machine gun hits. Knowing the enemy was fatally crippled, I ordered the U-boat to flank speed to complete our escape. With its only power now coming from the undamaged portside engines, the enemy zeppelin entered into a sharper starboard turn on course to bring it just behind us. This gave my men one further opportunity to fire at the other side of the ship as it flew by. They made good use of the target practice, destroying or disabling both portside engines and putting many huge holes in the fragile hull. Countless pieces of debris fell into the sea, barely 100 meters below the 300 meter-long leviathan. The enemy was now drifting powerless and headed nose-down toward the Atlantic Ocean. As we cruised away from the battle site, we could see even more large pieces falling from many places on the doomed enemy craft. Knowing that it might still take several hours for the slowly descending hulk to actually strike the sea, and aware that enemy destroyers were probably heading our way, I decided it would be wiser to complete our escape as quickly as possible rather than stay on station and attempt to render assistance to the enemy crew as they abandoned their dying zeppelin for the waves. We resumed an easterly course and lost sight of the enemy as the sun began to set.”
Signal is proud to report that, before returning to sea, Kapitanleutnent Handel and his brave crew were invited to dinner with Grandadmiral Doenitz himself at the Grand Hotel Nauticus in Berlin where they all received special awards for their skill and bravery in this unusual and successful combat with a flying monster ten times their size.
Editor’s note: In many respects this article is a fairly accurate portrayal of the engagement between USS Sacramento and U-367. However, as might be expected, Handel (or the Signal writer ghost-writing his report) misinterprets or exaggerates the damage to the airship. While it is true that the second salvo from U-367 virtually destroyed the control car and killed all officers present, damage to the surrounding hull was substantially less than Handel believed was the case. Handel was also incorrect in mentioning “fires” within the hull. There were no such fires. It is possible the German commander was seeing muzzle flashes from .50 calibre machine guns being fired ineffectually at the U-boat from positions on the lower keel gangways. Handel is also incorrect in reporting damage to Sacramento’s portside engines. In fact, neither portside engine was damaged in the engagement. He saw them cease operation because they were deliberately stopped on orders from Lieutenant Micah Barnes, who had by this time assumed command of the airship from the emergency control station on the lower fin. Also, despite Handel’s belief the airship was going to crash, it was never in serious danger of being lost during the engagement. The many rips and holes he describes in the exterior envelope, although large, had little effect on the ship’s overall buoyancy since they were on the bottom quarter of the ship. The ship had assumed a strong nose-down attitude due to gas loss in the forward gas cells, but never came closer than 200 feet to hitting the surface. In fact, the pieces of “debris” the German captain describes falling from the ship were slip tanks for water and sand bag ballast being released on orders from Lt. Barnes to help her reach equilibrium. Sacramento did face serious danger of crashing several times during her heroic struggle to reach home, but this would not have been witnessed from the German submarine. Unfortunately, the Navy never had the chance to interview Kapitanleutnent Handel and his crew after the war because U-367 was sunk with all hands by the Canadian destroyer HMCS Ojibwa on June 12, 1943.
The timeline depends on several PoDs, mainly USS Akron and Macon not being lost in the 1930's and the enactment of the 1928 "Airship Act" that would have give airship airlines favored status a the flag us carrier (this almost happened).
U.S. NAVAL RIGID AIRSHIPS 1923-1971
A DESIGN AND OPERATIONAL HISTORY
A DESIGN AND OPERATIONAL HISTORY
The Early Years
In view of the tremendous value of the Navy’s rigid airships during the 1941-45 Battle of the Atlantic, it is instructive to realize that, during several periods in the 1920’s and 1930’s, the entire program came very close to being eliminated. For at least the first fifteen years of their service in the US Navy, rigid airships were considered by all but a few advocates as unnecessary and ineffective experiments forced upon the fleet by a few important senior commanders and influential members of Congress representing districts which stood to benefit by the development of an airship industry in the United States.
From the beginning, both traditional “battleship admirals” and the new naval “airpower advocates” had little use for the zeppelin airship. In an environment of limited funding, traditionalists considered airships unproven competitors with light cruisers, submarines, and other vessels with clear offensive capabilities in naval warfare. Air power advocates, on the other hand, saw airships as directly competing for scarce aviation funds with flying boats and aircraft carriers. Since the only military mission the zeppelin was believed suitable for was unarmed scouting and reconnaissance, and even this had not been proven, most navy officials were unhappy to sacrifice either surface ships or airplanes to build rigid airships .
In fact, early US experience with rigid airships tended to support this pessimism. Both ZR-1, USS Shenandoah, and ZR-2, the unnamed British R-38, were destroyed in crashes before either ship had a chance to demonstrate any military value. Their loss reinforced the impression among the US public and many naval personnel that zeppelin airships were fragile craft, excessively vulnerable to weather conditions and inherently unsound. Lost in these accusations was the fact that neither ZR-1 (a copy of a 1916-vintage German naval zeppelin), nor ZR-2 (based on the very lightly-built German “height-climbers, and widely believed to be a particularly faulty design) were designed for North American weather conditions or rigorous low-altitude fleet scouting operations.
Even the highly successful ZR-3, USS Los Angeles, did very little to advance the cause of the rigid airship in the US Navy. Because ZR-3 was a new airship built by the Zeppelin Company as war reparations (to replace German naval zeppelins destroyed by their crews after the armistice), Britain and France insisted that the ship be built as a non-military vessel and not operated as a part of the fleet . Thus, while the ship served well to train crews and “show the flag” across the country for over 10 years, it had little opportunity to demonstrate any value to key decision makers in the Navy Department.
A Change in Fortunes
The Goodyear-Zeppelin Corporation was founded in 1923, as a joint venture of Goodyear Tire and Rubber Corporation, of Akron, Ohio, and the Zeppelin Company in Germany. This provided US airship designers with full access to all Zeppelin patents and trained design staff. Following in the early 1930’s, Goodyear-Zeppelin as well as the German Zeppelin Company proposed a number of subsidiary commercial airlines to operate trans-Atlantic and trans-Pacific passenger and mail service in Goodyear-Zeppelin built airships.
In 1928, following strong lobbying efforts from the Goodyear-Zeppelin Corporation, and as recommended by the United States Maritime Commission (USMC) and National Advisory Committee on Aeronautics (NACA), the United States Congress passed “An Act for the Establishment of a Commercial Airship Transportation Industry in the United States”, commonly referred to as “the Airship Act” . While this act initially provided no direct funding for the construction of airships or related industries, it set US policy to establish Goodyear-Zeppelin’s airship airlines as the official US flag carriers in any future trans-Atlantic or trans-Pacific airborne commerce, provided for all commercial airships to be constructed to US Navy specifications and be crewed by naval reservists, and require all civil airships and facilities liable for nationalization as naval auxiliaries in the event of war or national emergency.
In 1934, as an important element of the New Deal public works recovery measures implemented by Franklin Roosevelt, the Airship Act was amended to provide funding for several large airship-related construction projects. This included three new airship building sheds at the original Goodyear-Zeppelin Air Dock in Ohio; and four combined building sheds/hangars to be wholly operated by the Navy, two each at existing naval air stations (Sunnyvale, California; and Lakehurst, New Jersey).
In subsequent years, the Act was amended further to provide additional Works Progress Association (WPA) funding to build up to eight “civilian” airships similar in basic design to the Navy’s ZRS-4 (USS Akron) type airship, with passenger spaces occupying areas used as airplane hangers in the naval ships. WPA funds were also used to build other infrastructure supporting the commercial airship industry, including helium extraction plants, duralumin fabrication factories, hangers, and passenger/freight handling facilities. Also under the amended Airship Act, NACA established the Merchant Airship Academy in San Francisco, California, to provide training to civil (and potential naval) aircrew and air dock workers.
A vision of the future – the ZRS class ships
Despite positive developments in the civil arena, the role of the rigid airship in the US Navy remained uncertain through the early 1930’s. Goodyear-Zeppelin’s first rigid airship, ZRS-4, USS Akron, entered service in early 1931. A key improvement in this ship and its immediate successors was the provision of an internal hangar capable of handling and servicing five small Curtiss F9C fighter planes. In early training exercises, Akron was operated very conservatively and made little use of its airplanes. Employing tactics more suited to the German Navy in 1916, Akron’s commanders tended to use the airship itself as the scout, only launching planes after contact was made. As they soon discovered, attempting to locate and stealthily track surface ships in a gigantic silver object flying at only several thousand feet was virtually impossible. In fleet exercises, Akron was often seen and “shot down” by surface ships or ship launched floatplanes before she herself saw the ships. As her crew became more experienced with their ship, Akron began to use her airplanes more as primary scouts, but in two years flying, the ship had not demonstrated any real value to the fleet.
Akron’s sister ship, ZRS-5, USS Macon, entered service in 1933, and at that point things began to improve. Prior to this, all failings of the Akron in fleet exercises were automatically interpreted as a basic failing of the airship as a type, not as a possible product of poor crew performance or sheer bad luck. With two ships at its disposal, the Navy could now compare the performance of these ships and better understand how and why they performed as they did. Also, as would be expected, there was a natural evolution in the effectiveness of their commanders and crews as they learned from each other and became more experienced with the unique abilities and drawbacks of these giant ships.
The navy’s rigid airship program narrowly escaped a major setback in early 1935 when USS Macon suffered a serious casualty to her upper fin during a routine training exercise off Point Sur, California. A sudden gust of wind tore most of the upper fin off the ship, resulting in secondary hull damage and almost total helium loss in gas cells I and II. Only the extremely prompt and efficient action of her officers and men kept the ship aloft, and she was able to return to Sunnyvale with only minor additional damage. Not only did this accident help show that large rigid airships might be less susceptible to loss through battle damage than previously thought, it uncovered a potentially serious design flaw in the Akron/Macon fin design that could be adequately (if not ideally) corrected by strengthening of the forward fin attachment points, which unlike all previous and subsequent airships, were not cruciform structures.
Macon was repaired and back in service in July, and by late 1935, most senior officers accepted Akron and Macon as useful, if not exceptionally valuable, adjuncts of the fleet. The ships’ commanders had developed effective operational doctrine focusing on the use of the ships’ F9C fighters to greatly extend the effectiveness of the airships as strategic scouts, and their crews were both well trained and experienced. In the six “Deep Pacific” fleet problems undertaken in late 1935, the airships proved themselves very effective long range scouts, frequently locating and identifying “enemy” forces well in advance of other scouting vessels or carrier-launched scout planes. Although they often found themselves “shot down” as the problems evolved and the operational areas became more congested, this usually occurred well after they had provided information judged sufficiently important to justify their loss. Nonetheless, there was very little interest in investing additional funds for such large and expensive units which lacked any offensive capability of their own. It appeared Akron and Macon would remain the only fleet airships in the US Navy for the foreseeable future.
The Turning Point
A key event transforming the Navy’s grudging acceptance of airships to advocacy was Fleet Problem XIII in February, 1936. This featured a simulated “Orange” attack on a “Blue” base in the Panama Canal Zone. Orange, presumed to have occupied Pearl Harbor, was tasked with mounting successful airstrikes and shore bombardment of the Panama Canal Zone in preparation to a hypothetical invasion. Since the exercise presumed Orange had seized the initiative in the war, it was provided a powerful strike force centered on both main fleet carriers (USS Lexington and USS Saratoga) supported by the battleships USS Colorado, USS West Virginia, USS Tennessee, and USS New Mexico, and a mixed screening force of light cruisers, destroyers, and submarines. Blue was deliberately provided a much smaller defensive force comprising only two older battleships (USS Wyoming and USS Arkansas), the small carrier USS Ranger, two heavy cruisers, a few submarines, shore-based flying boats, coastal aviation, and the Akron and Macon. Although the problem was designed primarily to explore doctrine regarding the offensive use of aircraft carriers, it was also an ideal situation for the two rigid airships to demonstrate their unique and unmatched capabilities as high speed, high endurance, long range aerial scouts. This, along with a combination of ideal weather conditions for airship scouting and poor decisions by Orange fleet commanders, ensured their outstanding success.
Operating together under the overall command of Admiral William Moffett, and assisted by an unusually strong northwesterly tailwind, Akron and Macon moved at extremely high speed toward the Orange fleet’s projected approach route. This placed them in the general vicinity of the Orange fleet well before they would normally be expected to arrive. Very early in the exercise, Macon’s scout planes were able to locate the advance scouting screen for the Orange force in the open Pacific over 1500 miles from the Canal Zone and report the location and heading to the Blue main force.
Making excellent use of their scout planes and employing the low cloud cover to maximum effect, the airships were able to swing round the advancing enemy and take up station behind the main Orange force of battleships and carriers, just outside of visual range. Although Moffett expected his airships would eventually be located and “destroyed” by Orange’s carrier planes, they remained undetected throughout most of the problem, providing valuable coded information from their F9C scout planes to Blue’s main force.
On the other hand Orange, under the overall command of Admiral William Halsey, made far less effective use of its scouting assets. Although radio signals from the airships eventually gave Halsey a general idea of their relative bearing, he inexplicably made no serious effort to find and “destroy” them, claiming in his debriefing that he was worried his own scout plains might actually collide with them in the low clouds. In other respects as well, Orange aerial reconnaissance was unexpectedly poor.
Presuming inaccurately that the weak Blue fleet would seek to engage near the Canal Zone under the protection of its land-based aircraft and shore batteries, Orange continued to push ahead toward Panama at high speed. In fact, Blue Force commander Admiral Ernest King adopted the opposite strategy. Knowing that Halsey ultimately needed to enter Panamanian waters with effective air cover to offset Blue’s substantial land based air assets, King hoped to attack and eliminate one or both of Orange’s carriers early in the exercise. This would deprive Halsey of the air support he needed for a successful strike.
Toward the end of the second day of the problem, information provided by the airships allowed the Blue submarine USS Cuttlefish to infiltrate the Orange screen and “torpedo” USS Lexington, the referee on board the aircraft carrier ruling her “severely damaged” and requiring her to return to Hawaii. Halsey complied and detailed two destroyers to escort her.
Guided by information from Akron and Macon, King was able to avoid the Orange scout screen. Thus, by 0400 on the 3rd day of the exercise, the main Blue force consisting of the carrier USS Ranger and the heavy surface units had reached a position less than 150 miles northeast of the Orange main force.
At 0700, the Ranger launched its small strike force, which achieved complete surprise. Referees judged the Saratoga’s flight deck irreparably damaged, making her unable to operate aircraft for the remainder of the problem. They also ruled all of Ranger’s attacking aircraft lost in the action, but by then the damage was done. In two separate actions made possible by reconnaissance from Akron and Macon, Orange had lost all of its offensive and defensive air support. Halsey recognized that, in a real combat situation, any attempt to proceed with close-in shore bombardment without air cover could be disastrous. He then sought instead to bring the Blue force containing the Ranger into a surface action against his overwhelming force of battleships. Unfortunately, he was unable to locate the Blue ships, and they succeeded in slipping away.
By then, the two Blue airships had divided up, Akron continuing to shadow the main Blue force, with Macon tailing the “crippled” Lexington en route to Hawaii. Since the aircraft carrier had been ruled to be “heavily listing“ after the Cuttlefish’s “torpedo hits” it was not permitted to operate its aircraft, making it essentially a blind sitting duck. Knowing this, Admiral Moffett on the Macon prevailed on the referees to presume that, in an actual wartime situation, he would have a small number of 250lb bombs on board which could be changed out for the F9Cs’ external fuel tanks.
As required by the referees, Macon’s HTA unit simulated the “bombing up” of their aircraft by removing and then replacing the fuel tanks on three fighters currently in the hangar being refueled, and less than 2 hours after Moffett received approval from the judges, they were launched. The three planes soon arrived over the “crippled” carrier and made a perfect low angle bombing run across the length of the flight deck. To add insult to injury, the F9C pilots dropped toilet paper rolls as they flew by, all of them bouncing off the ship’s deck. Faced with such evidence, the referee on Lexington ruled the attack successful. Because the bombs were small, the Lexington was not “sunk”. However, the referee did rule that the attack started fires resulting in the loss of parked aircraft and personnel. In exchange, the three F9Cs were ruled “shot down” by Lexington’s anti-aircraft batteries and escorting destroyers. However, Macon’s attack showed that, in the right situations, aircraft carrying rigid airships could be effective offensive weapons.
As a result of Fleet Problem XIII, the rigid airship went from being a tolerated curiosity to a potentially valuable naval asset. All of the plans and designs which had been languishing for years at the Navy’s Bureau of Aeronautics (BuAer) Lighter-than-Air section now had a real chance of seeing fruition.
The Prewar Buildup, 1936-1941
The Navy requested and received authorization to procure two more ZRS type ships in the 1936 naval appropriations. The first ship was already well under construction at the Goodyear-Zeppelin Air Dock as the third commercial ship authorized under the amended Airship Act. She was based broadly on the Akron design, but her hangar bay was replaced by internal accommodations for 50 passengers, crew, freight, and mail. Following a redesign to restore the airplane hangar and bring all other elements of her design to operational naval standards, she entered service as ZRS-6, USS Wichita, in early 1937.
ZRS-7, USS Newark, was designed and built from the keel up as a naval airship and entered service in early 1938. Newark was built to a significantly revised experimental design proposed by the Navy’s Bureau of Aeronautics (BuAer). This corrected the design flaws which almost led to Macon’s loss in 1935 and, more significantly, replaced the internal airplane hangar and trapeze of Akron, Macon, and Wichita with a strengthened keel mounting six individual airplane launching stations and trapezes in tandem along the bottom of the ship. Although the planes’ partially exposed stowage restricted the ability of the HTA unit to perform extensive maintenance on them, the individual launching stations promised much quicker launching and retrieval operations. This system soon proved itself very efficient and, after USS Newark, no further naval airships were built with internal hangars.
In 1940, the Navy also received one additional airship from a very unexpected source: Nazi Germany.
When the European War broke out on September 1, 1939, the German airliner LZ-130 Graf Zeppelin had just completed its final westbound crossing of the North Atlantic season and was being serviced at the Lakehurst Air Dock. Because the Graf’s return voyage to Germany would of necessity take it over French or British airspace, and neither Allied nation would guarantee its safety, the ship was interned by the United States.
The Graf reigned as a hangar queen until April, 1940, when the United States Navy offered to purchase the ship from the Deutsche Zeppelin-Reederei. Initially, this offer was made, not so much to procure another airship for the Navy, but to restore full hangar capacity at Lakehurst for the new ZRCV airships under contract. After some negotiation, including a stipulation that the ship would not be based in the Atlantic or transferred to any Allied nation, the Nazi government approved the sale, believing that this highly visible and successful diplomatic deal with neutral America outweighed any potential risk that the ship might be of military value to the US Navy in the event of a war with Germany.
Although some thought was given to simply scrapping the ex-German ship, BuAer successfully argued for its refitting and incorporation into the fleet. At the time of its purchase, the state-of-the-art Graf was one of the largest operational airships in the world, capable of carrying a sizeable number of aircraft if properly refitted. In June the now-unnamed airship was flown to Goodyear-Zeppelin’s Airdock at Akron for conversion. Her passenger accommodation bay was reconstructed to house an airplane hangar with associated service and crew spaces, and several supplemental trapeze stations were added along the lower keel.
As requested by Germany, she was assigned to the Sunnyvale Naval Airship Training Squadron in California as ZRN-3. She received the name USS Bismarck. This odd name for a US ship in 1940 was ostensibly in honor of the capital of North Dakota, but there is anecdotal evidence it was indeed a deliberate double entendre to reflect the ship’s German origins.
Following the German declaration of War in December 1941, the airship was put into active service and assigned to Rigid Airship Patrol Squadron 3 at Lakehurst. Because her airplane hangar limited the size and capability of the aircraft she could operate she was rerated as a scout airship and designated ZRS-8. She was also renamed USS Belleau Wood, which also had German connotations, but of a nature far more suitable to a warship of the US Navy engaged in combat with Germany.
The ZRCV Ships – Aerial Aircraft Carriers
Before the ZRS-7 design was finalized, BuAer requested a series of design studies for the next generation of rigid airships for the navy. Unlike the previous ZRS ships which were not optimized to carry the larger and heavier naval aircraft coming into service, the ZRCVs were designed from the keel up as dedicated aerial aircraft carriers that would be able to operate a wide variety of modern aircraft. In their ultimate design, these became the largest operational airships ever built, being over 900 feet long and containing a volume of over 10,000,000 cubic feet of helium gas. The ships carried trapezes and launching/retrieval stations for up to 10 hook-on aircraft.
The initial 1936 design study offered by Goodyear-Zeppelin, ZRCV-A, was proffered prior to BuAer’s disenchantment with internal hangars and was little more than an enlarged version of Akron, retaining the deep ring construction, the lateral keels with internal engines, and an internal aircraft hangar. With a volume of 8,500,000 cubic feet, ZRCV-A could have carried as many as 8 aircraft similar in size to the F2C in a hanger one-third larger than that fitted on the earlier ship.
However, continued experience with the Akron-class ships had pointed out difficulties with their aircraft handling systems. The principal complaints expressed by airship officers involved the inefficient and complex monorail system that moved the F2C’s around in the hanger and the fact that only one airplane could be readied and trapeezed down for launching at a time. Even after aircraft operations from the Akron-class ships were perfected, it often took as long 20 minutes to ready and launch each plane, meaning that by the time the last airplane was out, the first could be nearing the end of its flight endurance.
Because recovery and stowage of each airplane was also a time-consuming matter, operation of all five aircraft at the same time was virtually impossible except over land or in the vicinity of an aircraft carrier where planes running short on fuel could land if necessary. Since this would be highly unlikely when the airships were operating in their intended role as long-range naval scouts, Akron and Macon rarely had more than two of its airplanes flying at the same time in their pre-war training flights. To improve this situation, airship commanders began to fit each ship with a series of “perches” on which pilots could hook, but this was an awkward and unsatisfactory solution.
Finally, in rejecting the ZRCV-A design, BuAer noted that the F2C was selected for service from the Akron-class ships solely because it was the smallest relatively high-performance airplane available that could fit through the hangar doors, not because it had any other particularly desirable traits. By the early 1940’s the F2C would be thoroughly obsolete for any useful purpose. Further, BuAer believed that any new purpose-built airplanes capable of being stowed in an internal airship hanger would be limited in size by the hangar and its door. Such airplanes would also be outclassed by their larger land- or carrier-based equivalents in a few years. Since the future ZRCVs were intended to operate with the fleet as dedicated aircraft carriers with an effective offensive capability, a way had to be found to both improve the efficiency of aircraft operations and provide for continual upgrades to larger and heavier airplanes capable of delivering effective ordinance loads.
Goodyear-Zeppelin had anticipated this problem and proposed design study ZRCV-B. This was very different from the Akron design. It reverted to “traditional” zeppelin practice with external engine cars and a strong ventral keel, widened aft of the control car to provide a long internal hangar, from which 8 airplanes could be hung in tandem on their own trapezes. As a concession to crew safety and comfort, however, retractable doors were provided beneath each aircraft to provide an enclosed service area
BuAer was not favorably disposed to this scheme as well, primarily because the long internal hangar and mechanisms required for the individual doors added considerable structural weight to the airship, reducing its useful lift. Although the hangar openings were capable of handling all existing single-engine naval aircraft, they would not be adequate for some of the larger types that were under design and expected to be entering service in the early 1940’s. Armed with initial positive experience from ZRS-7, BuAer rejected the airplane hangar altogether, requesting instead a revised design with aircraft stowed semi-externally on individual trapeze stations along the lower keel.
Goodyear-Zeppelin did not offer a new design incorporating BuAer’s recommendations. Instead, the firm provided additional calculations and anecdotal data to show that the efficiency of airship crews servicing and arming aircraft in a completely enclosed environment would outweigh
the weight savings gained by semi-external individual mountings.
The Navy was not pleased with Goodyear-Zeppelin’s reaction. Admiral Moffet then directed BuAer to request an outside ZRCV design competition which would not include Goodyear-Zeppelin. The Navy knew full-well that Goodyear-Zeppelin was the only American firm with the detail design capability and manufacturing plant capable of providing the US Navy with rigid airships, but felt that this step would prompt the Ohio firm to adhere more to BuAer’s demands in the future.
In fact, the competition produced several interesting outside proposals which, if the respondents had their own manufacturing capability, might have been seriously entertained. A total of ten proposals were received of which three were considered to have sufficient merit to warrant detailed design studies
As with the original competition that led to the ZRS-4 and her sisters, a proposal was offered by Dr. Karl Lanz of the WW1-era Schutte-Lanz airship firm in Germany. Lanz proposed to partner with an American firm (presumably Goodyear) to produce the airships if his design was accepted.
Lanz’s design was very similar to the ZRCV-B, although it varied in a few highly visible, but superficial, details. This airship was not looked upon favorably by BuAer, officially because it was very similar to the Goodyear proposal that had already been rejected. Further, the close similarity between the two proposals indicated to some BuAer reviewers that Lanz might have been working in collaboration with Goodyear, perhaps less to be the selected design contractor himself than to further document the advantages of Goodyear’s concept, presumably from a respected outside source. This suspicion is clearly evident in the following quote from an internal BuAer memo:
“…Not only does this [Lanz] design propose the same aircraft handling scheme we already rejected, our evaluation of the detailed schematics, show over 70% direct commonality with the Goodyear design. Hangar layout is is virtually identical, down to the placement of emergency lights, aviation fuel tanks and lines, and electrical wiring. Crew quarters are disposed similarly. The external engine cars are virtually identical in location, size, and internal layout. In fact, most of the main differences between this proposal and Goodyear’s ZRCV-B are cosmetic – fin and overall hull shape – differences in appearance that mask the overall structural and detail design similarities. It is our opinion that Lanz has either produced a thinly disguised copy of the ZRCV-B for his own purposes or is working in collaboration with Goodyear-Zeppelin…”
A more promising offer was made by a British team under Barnes Wallis and Neville Shute Norway of Vickers. Wallis assembled many of the original design staff responsible for the British rigid airship R-100, and had secured an arrangement to construct a prototype ship at Cardington. Had Vickers’ proposal been accepted, they also proposed to contract with Goodyear-Zeppelin for large-scale production.
In this case, however, there was clearly no collusion with Goodyear. The British entry borrowed much from the original 5,000,000 cubic foot R-100, including its geodesic internal bracing and relatively few longitudinal main girders. Instead of an internal aircraft hangar, the British design featured a long external aircraft handing gondola extending directly aft from main control station. Seven aircraft were arranged in tandem, each on its own trapeze system. In essence the aircraft were mounted externally from the main hull structure, but pilots and service personnel could access cockpits and engines from the fully enclosed gondola and walkways.
This approach avoided the awkward system of individual hangar doors proposed in the ZRCV-B, while still providing a largely enclosed space for most aircraft maintenance and servicing activities. BuAer found many elements of this proposal interesting and worth further study, but in the final analysis the Navy was uncomfortable sourcing the design of its next series of airships to a non-American designer. Also, some reviewers felt that the R-100’s structural scheme, which differed in many respects from “traditional” zeppelin or US practice, had not really been proven during the few short test flights and single Atlantic crossing the ship made before it was dismantled.
From the design perspective alone, the most interesting offer came from Metalclad Aviation, a successor to to the US Aircraft Development Corporation of Detroit, Michigan. This firm had designed and produced the small and revolutionary ZMC-2 rigid airship for the US Navy in 1927. The ZMC-2 was truly unique in that it completely abandoned the traditional fabric covered duraluminum zeppelin framework in favor of a stressed-aluminum skin, with only minimal internal bracing. Such a system was both lighter and less resistant to wear and tear than the traditional zeppelin framework, evidenced by the fact that ZMC-2 was still in active service almost 10 years after its first flight, and throughout its career suffered from far less osmotic gas loss that the Navy’s blimps or rigid airships.
Metalclad’s proposed ZRCV was in essence a massively scaled-up but less rotund ZMC-2 with a long external gondola for aircraft handling similar in concept to that offered by the British design. Like ZMC-2, the proposed Metalclal ZRCV eschewed the traditional fixed cruciform fins with elevators or rudders in favor of an interlinked system of eight separate movable control services.
Although BuAer felt that the Metalclad design had much to commend it, reviewers recommended that the Navy would be unwise to build a series of large operational airships on a design which had only been successfully demonstrated on a small prototype. However, the Metalclad concept showed enough promise to warrant further evaluation.
Although unwilling to accept Metalclad’s proposal for the current ZRCVs, BuAer proposed the procurement of one 3,000,000 cubic foot Metalclad training airship in 1941. These plans were put on hold and then cancelled by the outbreak of the Second World War. In any event, BuAer’s hesitancy about switching to the Metalclad concept was eventually borne out by the ZMCW-1 crash in 1965, which could be directly attributed to the lack of redundancy and rigidity inherent the metal clad principle.
Not surprisingly BuAer concluded that none of the outside proposals offered the combination of design quality and immediate constructability that the Navy needed and which Goodyear could provide. However, as expected, the review team liked several features of the Vickers and Metalclad designs, particularly the provision of individual aircraft service and launching facilities unburdened by hangar doors or other movable enclosures.
When informed of the results of the study, and certainly eager to protect their place as the US Navy’s only source of large airships, Goodyear-Zeppelin finally produced a design study that fully met all of BuAer’s requirements: ZRCV-C. With a few minor alterations, this design became the basis for all ZRCV ships completed before and during the Second World War.
Structurally, the ZRCV-C was similar to the rejected ZRCV-B, with the principal difference relating to aircraft handling, Rather than the long internal hanger in the earlier design, the ZRCV-C borrowed from the existing ZRS-7 and featured a series of 10 individual aircraft trapeze stations located in tandem beneath the hull to service, launch, and retrieve airplanes. As in the ZRS-7 the airplanes would be carried on their own trapezes partially outside of the hull, only the cockpit and upper fuselage being readily accessible from an enclosed area.
Although this would complicate aircraft access and maintenance when biplanes or high-wing aircraft were operated, BuAer presumed at the time that future aircraft embarked on the ZRCVs would be most likely be low wing monoplanes. As later events proved, this presumption was incorrect. By 1943, the main ASW attack aircraft on all ZRCV ships was the high-wing Harrier flying boat, which necessitated external stowage of virtually the entire aircraft, service being achieved by retractable crew and equipment baskets. Although this worked sufficiently well, Harrier servicing and maintenance on a ZRCV remained an uncomfortable and potentially hazardous task for service crews, requiring the airship to be flown at 20kts or less when being done.
In the 1938 naval appropriations bill, funding was authorized for 10 ZRCV ships to be completed over the following four years. The first two, ZRCV-1, USS Tulsa, and ZRCV-2, USS Intrepid, were commissioned in 1940. Also in 1940, as part of the overall military buildup authorized by President Roosevelt, construction of all commercial airships was suspended and the ZRCV program was accelerated. ZRCV-3, USS Anchorage, ZRCV-4, USS Sacramento, and ZRCV-5, USS Bon Homme Richard were completed in 1941. All five ships were based at Lakehurst, and before US entry into the war, they were clandestinely providing ASW air cover for Britain-bound convoys under the guise of “operational training”.
The 1938 Training Airship Program
Once all 10 ZRCV’s were scheduled to be fully operational in 1943-44, the Navy anticipated relegating the three oldest ZRS ships (USS Akron, Wichita and Macon) to a dedicated training squadron. The sole airship used for crew training in the 1935-40 period, USS Los Angeles, lacked the ability to handle aircraft and consequently had no remaining value to an airship service whose raison d’etre had become carrying airplanes.
However, until the entire ZRCV fleet was in place, all ZRS ships would remain operational fleet vessels. As an interim solution, BuAer proposed two smaller aircraft-carrying training airships (the ZRN-class) in 1938. These would replace the old Los Angeles. However, the ZRN’s would be sufficiently modern and capable to serve in an operational capacity if the need arose.
The 1938 ZRN program was very controversial, both in the Navy and out.
Many flag officers questioned the need for dedicated naval training airships at all since one of the purposes for the original Airship Act and Goodyear-Zeppelin’s two existing commercial airships was supposedly to provide a pool of trained reservists for the naval airship service. Many in congress argued that the Navy already had several aircraft-carrying ZRS airships and that, surely, at least one of them could be repurposed as a crew trainer with no additional appropriations
Others, supported by no less a figure than President Roosevelt, felt that the ZRN ships were far larger and far more capable than necessary for mere training purposes. Why, they asked, did the proposed ZRN have to be a 4,000,000 cubic feet ship larger than the famous Graf Zeppelin I that flew around the world? Why did it have to operate three airplanes? Why did there have to be two airships? Roosevelt, never a big supporter of the Navy’s rigid airships, clearly believed that the entire ZRN program was a backdoor attempt by BuAer to expand the Navy’s operational force of fleet airships beyond the numbers authorized by Congress in 1938, merely by calling two of them training ships.
The President then ordered BuAer to develop preliminary designs for the shortest, smallest, and least expensive airship that could provide the Navy with basic training in the operation of airships and hook-on aircraft. BuAer dutifully developed two alternative designs, each for an airship of approximately 1,000,000 cubic feet. One was a small, rotund, zeppelin-style rigid airship with space for a single airplane landing/service station in the lower keel immediately aft of the control car. The other was 1,200,000 cubic foot metalclad airship with the control car itself containing hook on facilities for a single airplane.
These designs demonstrated that an airplane-carrying airship built to the smallest possible dimensions was worse than no airship at all. The traditional zeppelin design would be only marginally less expensive than the planned ZRN, but have far less capability. The metalclad, with its stressed skin envelope, would have little value for training flight personnel in the inspection and maintenance of the Navy’s existing and planned fleet of zeppelin-style airships. Armed with this information, Admiral William Moffett eventually succeeded in convincing Congress and the President to fund both ZRN airships as originally proposed, and they were included in the final 1938 Naval Appropriation.
Both ships were built by Goodyear-Zeppelin to a design prepared by C.P. Burgess of BuAer. ZRN-1 USS San Juan was completed in early 1940, followed by ZRN-2 USS Austin in mid-1941. With a gas capacity of slightly under 4,000,000 cubic feet and a length of 710 feet, the ZRNs had trapezes and launching stations for 3 aircraft. Despite President Roosevelt’s suspicions, the Navy never gave any thought to incorporating either ship in the active fleet during the Second World War. Both ships were based at Sunnyvale, which became the principal training station for the naval airship service. The ships spent the bulk of the war at Sunnyvale until the rigid airship program was disbanded.
The Second World War
Developing a New Operational Doctrine
It was only with the ZRCV ships that the rigid airship came into its own as a serious component of the United States Navy. However, until the outbreak of the Second World War, their raison d’etre was still poorly understood.
Following the attack on Pearl Harbor in December 1941, the Navy’s priorities changed. Aircraft carriers and airplanes assumed highest priority, and even those supportive of the airship believed the ZRCV program should be curtailed. Only two ZRCVs already nearing completion were finished: ZRCV-6, USS Honolulu, and ZRCV-7, USS Manila Bay. The remaining three ships were cancelled. Many airship building sheds were transformed into assembly plants for a variety of naval aircraft. However, design work on the “next generation” ZRCV continued, and three sheds at Goodyear were reserved for the repair, refitting, and modification of the operational airships.
Prior to 1940, BuAer, as well as many of the most senior officers in the Navy’s lighter-than-air sections, initially saw the ships’ prime function in terms of the 1937-1938 Pacific Fleet Problems, most of which were designed with Japan as the likely enemy. Both USS Akron and USS Macon participated in these exercises, which amply demonstrated the ability of the aircraft-carrying large rigid airship as a fast, long range, scout. The ZRCVs presumably would have given this long range reconnaissance wing a credible offensive capability as well.
All of these plans were predicated on the Navy’s decades-old “War Plan Orange”, which presumed that, in the event of war with Japan, the small US Navy Asiatic squadron and unfortified advanced bases would be overwhelmed fairly early in the campaign. This would force the main Pacific Fleet to steam west across the Pacific from Hawaii to either contest ongoing Japanese invasions in the Philippines, or barring that, seize bases in the Marianas from which it could begin the gradual economic blockade of Japan. It was presumed that in either case, the Pacific Fleet would have to defeat the Japanese Navy in a decisive engagement south of Japan, probably relatively early in the campaign.
In this context, the ZRCV’s would operate with light cruisers and aircraft carriers as a fast scouting screen in advance of the US main battle line and its support train as it steamed westward from Hawaii. Their role would also be to locate and assist in the destruction of any Japanese submarines that were expected to be lying in wait for the US force along its route.
It was presumed that the ZRCV’s would likely be lost if they chanced upon Japanese aircraft carriers, although airship advocates offered the promise that the airships’ small strike force of dive bombers could exact some retribution by damaging the Japanese carriers, and limiting their usefulness as scouts or offensive weapons in the fleet action followed.
As later events in the Pacific showed, this was not a specious argument. Under existing Japanese doctrine that focused on a single “decisive battle”, the IJN’s aircraft carriers were not designed, nor were they expected, to take battle damage and maintain an operational capability. They were designed essentially as “first strike” weapons whose key purpose was to locate and destroy US aircraft carriers in the initial stages of the expected fleet action, and then hopefully assist the battlefleet by providing aerial reconnaissance and conducting additional airstrikes on the enemy with whatever surviving aircraft they had. Key to success was the presumption that Japanese carriers could strike first before they received damage that rendered their own flight decks or hangars inoperable
The 1942 Battle of Midway and later actions would abundantly demonstrate that IJN aircraft carriers were probably even more susceptible to crippling damage from a few bomb strikes or torpedo hits than anticipated. Given this, one must wonder what might have happened if even a single solitary ZRCV on picket duty had encountered the Japanese Pearl Harbor strike force on the western approaches to Hawaii.
Because airships had less endurance than surface ships, the Navy in 1936-1938 converted three fleet oilers, USS Richland, USS Howard, and USS Stennis, to serve as airship tenders. These were similar to, but larger than, the old USS Patoka, each with a large high mast and ample supplies of helium, fuel, and other supplies to allow the airships to operate for extended periods with the fleet.
Prior experience with Patoka had been limited to sheltered harbors or bays. Experiments in 1938 with the ZRS USS Wichita showed that mooring and servicing a rigid airship from a tender on the open sea was an unreliable proposition. It was often impossible to moor the airship in anything but the calmest seas. In addition, even when the Wichita had been successfully moored, she was forced to uncouple several times to avoid damage when sea and wind states conflicted.
Experiments to use the obsolescent aircraft carrier USS Ranger as a base for airship operation avoided the mooring difficulties, but the airship could not be “docked” to the carrier’s deck, requiring it to be in full flight status while taking on fuel or ballast. In the late 1930’,s underway replenishment of surface ships was still an experimental and dangerous process, and this was when both vessels were operating in the same fluid medium. In the case of airships and a surface replenishment ship, the vessels are within completely different fluids, making their chance of breaking fuel lines or even colliding with each other far more likely. And the collision of a rigid airship with the upper works of a surface vessel would almost certainly be fatal to the airship.
As a result, the Navy decided that it would be necessary to station tenders in sheltered advance locations such as Midway Island, Wake Island, or (rather optimistically) the Japanese occupied Marianas. In fact, the virtual impossibility of effectively servicing rigid airships at sea was one of the reasons the decision was finally made in 1940 not to station any airships with the Pacific Fleet in Hawaii.
The following excerpt from BuAer Report 1939.A offers a succinct discussion of the matter:
“The airship’s abilities and drawbacks are such that it can never hope to be the advanced fleet scout the Navy had in mind in 1935-36. No way has yet been found to provide replenishment to airships operating for extended periods at sea.
Although far faster than surface scouts and aircraft carriers, airships will be unable to operate for any extended duration with the Fleet once it enters the western Pacific, unless advance stations in Wake Island, Guam, or the Philippines, are still available. If they scout ahead at their cruising speed of 60kts, they will arrive in the Western Pacific well ahead of other fleet assets, and may find the bases at which they hope to replenish occupied or under siege by the enemy. In addition they would be subject to attack by enemy naval or land-based aircraft with little means of self-protection. The airships would then be forced to return to Hawaii or perhaps Midway for replenishment and be unavailable to provide tactical scouting for the fleet when it arrives. As a result, the only real use of the Navy’s rigid airships in the Pacific would be in a maritime reconnaissance role once suitable bases are built or recaptured or in an ASW capacity in the central and eastern Pacific. Attention is drawn to USS Macon’s success in the recent Midway problem, in which she was very successful spotting the submerged submarines USS Cockle and USS Snapper and keeping them under observation for much of the exercise.
This would appear to be the best current use of the new ZRCV ships currently under construction. Whether the ships are based with the Pacific or Atlantic Fleet should be determined based on diplomatic and geopolitical developments this study is not intended to address”
The BuAer report was completed in October 1939, after the outbreak of the European War. Although at the time the US had adopted a policy of strict neutrality, both the Navy and the Army (especially the Air Corps) were developing strategic plans to address the contingency of possible war with Germany. For the US Navy, this once again meant having to face the specter of German submarines engaged in unrestricted warfare against US trade and commerce in the Atlantic. As events transpired in 1940 and early 1941, this was proven out even before the United States was thrust into the Second World War.
Basing, Facilities, and Organization.
Initially, with the exception of training airships based at Sunnyvale NAS in California, all rigid airships were operated in the Atlantic theatre of operations. Several major bases and a number of secondary facilities were developed for the rigid airship service
Lakehurst Naval Air Station The primary rigid airship base throughout the war was Lakehurst Naval Air Station, New Jersey. It was administrative home of the entire US Navy Airship Operational and Research Commands throughout its existence and was also the designated home port for all rigid airships active in the Atlantic theatre of operations. The base was initially commissioned in 1921 and had been expanded in 1935-41. By 1942, Lakehurst NAS comprised three new double hangars capable of sheltering up to six rigid airships simultaneously, several low mooring masts and circles on which additional ships could be grounded while waiting for space in the hangers, and the complete range of airship support facilities.
The original 1921 Hangar No.1, as reconstructed in 1939, was capable of sheltering one ZRCV or ZRS-class ship or two smaller ZRN’s. Lakehurst Hangars No 2, 3, and 4, completed in 1938-41, were massive twin structures designed to shelter two ZRS or ZRCV-class ships each. Lakehurst NAS also possessed landing strips and sheds for the airships’ HTA units. During the war, the airfield was expanded to handle the complete range of land-based aircraft operated by the USN.
Norfolk Naval Air Station In 1940 a single twin hangar for ZRCV ships was completed at the Norfolk NAS in Virginia, supplemented by a complete shop capable of maintaining, repairing and servicing the airships. In 1941-42 two ZRCVs, USS Sacramento and Tulsa, were detatched to Norfolk where they could coordinate closely with other naval aircraft and ships struggling to counter Germany’s “Operation Drumbeat” U-boat offensive off the US east coast. After early 1943, no rigid airships were permanently based at Norfolk, although the hangars were often used by ZRS and ZRCVs on temporary details.
Sunnyvale Naval Air Station Prior to 1940, Sunnyvale NAS in California was being developed as the home base for the large number of rigid airships planned for the Pacific Fleet. Consequently, Sunnyvale possessed a capacity well in excess of what it eventually needed as an LTA training facility. This comprised two large twin hangers for four ZRS or ZRCV ships as well as its original single hangar built for USS Macon. With the consolidation of the Naval Airship Operational Command at Lakehurst, only the original Hangar No. 1, which could just fit both smaller ZRNs, was kept in service. One bay of Hangar No. 2 was kept active as an airship maintenance and repair shed. Remaining hangars and all other base facilities were refitted to house non-rigid airships as well a variety of other naval aircraft operating from the large airfield.
Goodyear-Zeppelin Airdock (“Akron NAS”) In any discussion of “major airship facilities”, mention must also be made of the Goodyear-Zeppelin Airdock, in Akron, Ohio. By 1941 the Akron complex consisted of two giant double fabrication hangars capable of constructing four ZRCV ships concurrently, one operational hangar for a ZRCV-class ship, the original Goodyear-Zeppelin ZRS construction hangar, and numerous other facilities devoted to the construction, repair, and maintenance of the Navy’s rigid airships and blimps. During the war, Goodyear also became a major builder for US naval aircraft, particularly Grumman Wildcats and Vought Corsairs. This necessitated the addition a large airplane manufacturing plant and a military airfield. By 1945, the Goodyear Airdock had become the largest single privately- owned aircraft manufacture and maintenance complex in the United States.
Although the Goodyear-Zeppelin Airdock remained a private corporate facility, the close – many would say incestuous - relationship between Goodyear and the US Navy’s airship establishment meant that Goodyear’s airship works often functioned as a naval facility. Not only did Goodyear build all of the Navy’s airships, their initial test flights and final pre-acceptance shakedown cruises under mixed Goodyear-Navy crews were based at Akron. In 1941, the Navy established a small administrative facility immediately adjacent to the Goodyear Airdock, consisting of barracks for officers and enlisted personnel, administrative offices, preflight school for both LTA and HTA crews, and other support staff. This was duly commissioned the “Akron NAS” although it neither few, built, nor maintained any naval aircraft.
Mirroring the Navy’s practice of satellite bases for its principal training and operational bases, Goodyear also maintained mooring masts at several company properties throughout the central USA and in Amarillo, Texas, where much of the helium used in the airships was produced. The Navy often used these outlying Goodyear properties as destinations for long-distance shakedown cruises before officially the accepting rigid airships into service.
Secondary Airship Bases
In addition to the above major facilities, the Navy constructed a number of secondary airship bases for its rigid airships, a number of which featured a large “temporary” wooden hangar capable of housing a ZRCV-sized ship, a single mooring mast and mooring out circle, and replenishment facilities. Unlike the primary bases, the secondary facilities had limited maintenance capability and were not equipped to repair substantial damage to the ships or their aircraft.
At wartime peak in 1944 there were five outlying secondary bases in the US with rigid airship hangars and most necessary supply and replenishment facilities. These, together with other facilities, also served as home bases for the Navy’s large fleet of small blimps used in air-sea rescue and coastal ASW work. Although the blimps were provided their own hangars on some bases, this was not always the case, a condition that on occasion resulted in operational or logistic difficulties.
Pensacola NAS, Florida boasted one large wooden hangar capable of sheltering and servicing two ZRCV or ZRS ships on detached duty and was also the home base for two blimp patrol squadrons. ZRCV and ZRS ships often operated from Pensacola. In addition to its LTA support role, Pensacola was a major base for land-based patrol aircraft, pilot training, and flying boat operations. Its location in Florida was ideal to provide ASW coverage in the Atlantic, Caribbean, and Gulf of Mexico.
Ceiba NAS, Puerto Rico contained a large wooden hanger capable of sheltering and servicing one large rigid airship, but only limited maintenance and repair facilities. Although originally intended as a temporary base of rigid airships on detached duty, it also served primarily a home base for blimp ASW and Air-Sea Rescue squadrons, eight of the smaller non-rigid airships usually being housed in the large hangar. Rigid airships were never based at Ceiba for any extended periods, and even temporary use of the base by rigid airships was discouraged because of logistical problems, a fact that was brought home by the USS Honolulu landing accident in 1943.
South Weymouth NAS, Massachusetts was one of the navy’s chief blimp bases, but also boasted a single large steel hangar and mooring out circle capable of handling a ZRCV airship. Like Ceiba, South Weymouth never hosted rigid airships on extended stays, primarily because of its relatively close proximity to Lakehurst. At various times, USS Wichita, USS Sacramento, and USS Intrepid operated from Weymouth.
Tillamook NAS, Washington boasted two large airship hangars capable of handling, servicing, and sheltering ZRCVs. It was originally commissioned as an operational satellite base for Sunnyvale NAS. However, when all fleet airship operations were moved to Lakehurst, Tillamook was repurposed for ASW and Air Sea Rescue coastal blimps and aircraft. Occasionally one of the ZRNs from Sunnyvale would conduct training flights to Tillamook, but it never hosted a rigid airship.
Houma NAS, Louisiana contained two large airship hangars suitable for use by ZRS or ZRCV airships. It was ideally located for airships and other aircraft undertaking ASW and Air Sea Rescue operations off the busy mouth of the Mississippi River, a common target area of U-boat activity early in the war. The facility was also a very active blimp base. At one time or another in 1942-43, USS Akron, USS Macon, USS Belleau Wood, USS Honolulu, and USS Bon Homme Richard were detatched to Houma. However, only Macon ever stayed for an extended period at Houma.
Non-US Facilities
Bartolomeu de Gusmão, Brazil. The commercial Zeppelin hangar at this airport near Rio de Janeiro was the only modern airship facility in the western hemisphere outside of the US. After Brazil entered the Second World War in 1942, the Brazilian Air Force made the facility available as a distant basing option for US rigid airships patrolling the South Atlantic. Several additional smaller hangars were built to house a number of blimps that also operated from the facility. Because of its fully equipped zeppelin hangar and complete servicing facilities, “Barty” was well suited for US rigid airship operations. Several ships, particularly USS Belleau Wood (the former German Graf Zeppelin II and one of the ships for which the Brazilian hangar was specifically built) were frequently detached there. In fact, Belleau Wood so often operated from Bartolomeu de Gusmão that the US gave serious consideration to transferring the airship to the Brazilian Air Force under lend-lease. Accordingly, prospective Brazilian LTA flight and ground personnel were trained at Sunnyvale NAS, graduating in early 1945. However, by then the war was nearly over and, given the reduced enemy submarine threat, Brazil no longer desired the airship and the plan was cancelled.
Other Facilities At one time or another during the war US rigid airships, including the ZRN training squadron, made use of temporary mooring mast facilities erected in Hawaii, Cuba, Iceland, the Panama Canal Zone, Gibraltar, Casablanca, Midway Island, and Guam. Ships were never based at these sites; they were only used as way stops, or in the case of ZRNs training destinations. After the liberation of France in 1944, the prewar French naval airship base at Cuers-Pierrefeu near Toulon became available to US airships. During the last months of the war, Toulon often served as an extended way stop for US rigids on transatlantic sweeps despite the fact that its hangars were not quite long enough to completely enclose a ZRCV. It was, however the most suitable existing European site for his purpose. Although Britain retained number of large airship sheds from its 1920-31 airship program, the Navy never considered using them, in large part because southern England remained an occasional target for Luftwaffe raiders (and later V-1 and V-2 missile attacks) until the end of the war.
Organization
In 1942, the Navy’s LTA program was divided into three overall Commands.
The Naval Airship Training and Reserve Command was centered at Sunnyvale NAS and was responsible for all aspects of LTA training and recruitment. Three largely independent training programs existed for Rigid Airship Training Services, Non-Rigid Airship Training Services, and Ground Support Services. Separate from the above units, both ZRN airships, as commissioned ships under the command of their own Commander and Executive Officers, comprised the Naval Airship Training Squadron.
The Rigid Airship Operations and Research Command based at Lakehurst combined three Divisions: the Base Operations Division responsible for building, maintaining, supplying, and staffing all airship bases, a Research Division responsible for coordinating all research relating to the design and operation of rigid airships and their associated equipment, and three Rigid Airship Patrol Squadrons consisting of all the commissioned airships, each ship under the command of its own captain (usually a Commander in formal rank) and executive officer.
The Non-Rigid Patrol Airship Division was very much a stepchild, despite the large numbers of blimps (over 75) eventually procured by the US Navy during the war. Blimps were treated as aircraft, not commissioned ships in the US Navy. Thus, whereas effective commanding and executive officers of a rigid airship would accrue promotion credit toward captaincy of larger surface ships and eventual flag officer status, this avenue was not available to the men (usually lieutenants or even ensigns) who commanded blimps. Individual blimps were assigned as needed to patrol squadrons (ZNPs) based at the many rigid and non-rigid airship bases, with the primary functions being near- coastal ASW patrol and air-sea rescue. Blimp operating doctrine specifically discouraged these craft from initiating combat with enemy submarines unless the U-boat constituted an immediate threat to a merchant ship or the airship itself. Because of these limitations and the existence of 12 operational rigid airships, many in the Navy questioned the very rational for the large blimp fleet at all. However, if the log books and reports of German submarine captains are to be believed, the sight of blimps (often referred to as “dwarf Zeppelins” by the Germans) often forced submarines to submerge and break off pursuit of convoys, possibly saving countless lives.
Operations
Regardless of where rigid airships might operate, they were all assigned to one of three Rigid Airship Patrol Squadrons home based at Lakehurst NAS or to the Naval Airship Training Squadron based at Sunnyvale NAS. Although all three patrol squadrons called Lakehurst NAS their home, each had largely non-overlapping operational areas of responsibility.
Rigid Airship Patrol Squadron 1 (ZRP-1) comprised the 4 US-built ZRS-class ships, USS Akron, USS Macon, USS Wichita, and USS Newark. ZRP-1’s home base was Lakehurst. Since its ships were significantly smaller, shorter ranged, and less capable than the ZRCV ships, ZRP-1 typically operated on convoy escort, air/sea rescue, and ASW duties in the western Atlantic and Gulf of Mexico. Individual ships were often detailed to secondary bases in Florida, Puerto Rico, or Texas, where they sometimes operated in so-called “hunter-killer” groups with detached ZRCV ships. Late in the war, USS Akron was detached to Sunnyvale NAS and ended the war operating from Guam. Other than Akron, ZRS-ships rarely operated from overseas bases.
Rigid Airship Patrol Squadron 2 (ZRP-2) included the ZRCVs USS Tulsa, USS Intrepid, USS Anchorage, and USS Sacramento. ZRP-2’s ships were all home based at Lakehurst, but detached units were often detailed to satellite facilities in Norfolk or Weymouth for extended periods. From these bases as well as temporary masts in Iceland, ZRP-2 provided convoy escort, air/sea rescue, and independent ASW work primarily in the north Atlantic sea lanes.
Rigid Airship Patrol Squadron 3 (ZRP-3) consisted of three ZRCVs (USS Honolulu, USS Bon Homme Richard, and USS Manila Bay) and the former German airliner USS Belleau Wood. ZRP-3 was also home based at Lakehurst. However, ZRP-3’s principal theatres of operation were designated the Gulf of Mexico, Caribbean, and South Atlantic, where they served primarily in the ASW hunter-killer role, either independently or in concert with other airships, surface units, or aircraft. Ships of ZRP-3 often spent extended time at secondary bases or masts in Puerto Rico, the Canal Zone, and Brazil. Belleau Wood, in particular, was often detailed to Bartolomeu de Gusmão in Brazil. The hanger there had been specifically designed for her and her sister Hindenburg when she was a commercial German airship, making it well suited as a nearly permanent base-of-operations for the ship.
Naval Airship Training Squadron The two US-built ZRNs spent the entire war assigned to Sunnyvale NAS, California, although long distance training flights often saw them based temporarily at secondary facilities in Oregon, Washington, the Canal Zone, and Hawaii. While training over 1500 seamen and HTA aircrew for the airship service, they also conducted convoy escort missions between California and Hawaii under virtual wartime conditions. After 1944, both ships were outfitted with advanced air-search radar and were utilized in the unpublicized defense against Japanese balloon bombs, a number of which were destroyed by the airships’ own HTA training units.
Non Rigid Airship Operations
Although not the subject of this study, the US Navy also made considerable use of non-rigid “blimps” in ASW and air-sea rescue work. These craft, considerably smaller than the rigid ships, were considerably less expensive to build and man, and were ordered in large numbers from Goodyear aviation. The most common “K-class” airships operated only from the mainland USA and were chiefly responsible for patrolling US coastal waters and conducting ASW searches in the areas of convoy assembly points. Far too small to carry aircraft or more than small number of depth bombs, the blimps’ principal role upon sighting an enemy submarine was to call surface help and maintain station over the target. In practice, they eventually served primarily as coastal patrols and in the air-sea rescue role.
The Overall Performance
Prior to late 1943, rigid airships in the Atlantic only operated within their out-and back radius of action (roughly 3000 miles for the ZRS ships and 5000 miles for the ZRCVs). While all the ships were fully capable of transatlantic convoy escort or patrol missions with fuel to spare, the only suitable basing and hangar facilities not in German hands were in England, and even here, the Navy did not want to risk its airships in the relatively congested airspace of northwestern Europe where they could be subject to Luftwaffe attack, either on the ground or in transit.
With the successful Anglo-American invasion of North Africa, transatlantic ASW missions became possible. Temporary mast facilities were erected at Gibraltar, and by late 1944, after the liberation of France, ships could put in at the old French naval airship base near Toulon.
It is probably not an exaggeration to say that US rigid airships were as instrumental in securing ultimate victory in the Battle of the Atlantic as any other naval aviation assets. They and their hook-on planes provided a degree of 24-hour aerial coverage in the vicinity of convoys which was unmatched by either land-based air or escort carriers. They could launch and retrieve their planes when sea conditions made operation from small escort carriers impossible.
However, the airship (both rigid and non-rigid) was really not ideally suited to close convoy escort. Airships were highly visible from a surfaced submarine at long distances. This frequently allowed submarines to locate and converge on convoys under close airship escort in situations where the merchants might otherwise have gone unnoticed. Also, the close proximity of a visible ZRCV to convoys at times had the opposite, equally unhelpful effect, of making a submarine abort a possible attack when effective escorts were present that could destroy the U-boat.
As a result, the operating doctrine for rigid airships shifted away from close escort to independent patrol and the hunting and killing of U-boats. This was particularly their role in the mid-Atlantic “gap” outside the range and endurance of most shore-based ASW aircraft. Also, airships could conduct sweeps and patrols at night and in poor visibility conditions that grounded many most other aircraft. ZRCVs could also operate their aircraft when rough sea conditions made operations from small escort carriers problematic. As patrol vessels the airships’ relatively high speed in comparison to surface ships and extremely high endurance in comparison with aircraft played real dividends.
From 1943 on, the airships were equipped with the largest and longest ranging air/sea search radars, towed and buoy sonar and hydrophones, and magnetic anomaly detection (MAD) equipment. The ZRCV-class ships were, in particular, well-armed with depth bombs, standard bombs, and other anti-ship weapons, both for use by their hook-on airplanes and the airship itself. Toward the end of the war, acoustic homing torpedoes were added to this arsenal. As a result, the ZRCVs were more than capable of both finding and pressing home attacks on submarines.
Because of their long endurance, the airships could loiter on ASW searches in the “gap” for up to a week, and although their attack planes had limited range and relatively poor offensive capabilities in comparison with their land-or carrier based counterparts, they could be rearmed and refueled by the airships while on station. For these reasons, being located, tracked, and engaged by a ZRCV was one of a u-boat commander’s worst nightmares.
Although the older ZRS type ships had to rely on other aircraft or surface units to engage and sink German submarines, they and their aircraft were excellent in the reconnaissance role. They also possessed an endurance almost equal to that of the larger ZRCVs. When appropriate, it was not uncommon to see a ZRS and ZRCV ship operate together in a hunter-killer capacity – the ZRS being one of two “hunters” and the ZRCV the “killer”.
Airships also proved to be less vulnerable to damage from submarines’ deck guns than had been feared. Unless a lucky hit was made on the control stations, engines, or fuel systems, a large rigid airship was virtually invulnerable to the standard anti-aircraft armament shipped by wartime u-boats. Even when such hits were made, severe damage never led to loss of the ships. In many, instances, airships would return to base with dozens of holes from 20mm, 37mm, and even 88mm shells that had passed harmlessly through the ship, in a few cases without its crew even being aware they had been hit.
Only once was a rigid airship almost downed by a submarine. This involved an engagement between USS Sacramento and U-367 several hundred miles off the Maryland coast in July 1942. Sacramento encountered the surfaced submarine on July 2, shortly after beginning a standard ASW patrol. She forced the submarine under and tracked her for several days, allowing the enemy to surface only briefly, at which time she used her aircraft to force her to submerge again. Up to this point the mission was going according to the textbook.
But then the submarine sprang a surprise on Sacramento. After being tracked and depth bombed by the airship’s aircraft, the submarine surfaced, issuing dark black smoke from its conning tower. Believing his foe was seriously damaged and possibly close to surrender, Sacramento’s commander elected to close for a direct engagement.
What he did not realize was that the smoke was a ruse, serving the double purposes of making the submarine appear damaged and masking the U-boat’s gun crews while they prepared their weapons. As she closed the range, Sacramento began to receive fire and was quickly struck by well-aimed cannon and machine gun fire. This destroyed both portside engine cars and peppered the immediately adjacent gas cells with shrapnel. In addition, the control car was struck by a combination of 88mm and 20mm fire, killing all 14 crewmen in the control car, including the ship’s Commander and Executive Officer. Assuming command from the aft emergency station, the Sacramento’s senior surviving lieutenant immediately broke off the engagement, while the only slightly damaged U-367 chose to escape rather than risk further combat.
Sacramento eventually reached Norfolk NAS on the power of only two of her original four engines, and losing critical amounts of lifting gas. To make land, she had been forced to jettison her entire compliment of aircraft (which, lacking conventional landing gear could not be flown off), all remaining weapons stores, all standard ballast and any unnecessary fuel. In spite of this and her sailmakers’ emergency repairs to the leaking gas cells, she was still heavy from loss of helium, requiring her to be flown at maximum speed with a 20 degree nose up attitude to maximize dynamic lift. Sacramento landed hard and incurred significant damage to her lower fin and bottom keel, requiring extensive repairs.
Almost certainly, had this action occurred in mid-Atlantic, the airship would have been lost. In a subsequent Board of Inquiry, Sacramento’s commander was faulted for being unnecessarily aggressive in seeking to bring a surfaced enemy into close action without first using his aircraft to determine the extent of damage and eliminate the submarine’s anti-aircraft capabilities. He was also faulted for pressing the engagement and not immediately seeking to disengage when the submarine opened fire. Her commanding lieutenant and 16 crewmen received the Navy Cross in recognition of their skill and courage in saving the damaged airship.
Immediately following the Sacramento inquest, the Navy issued orders prohibiting airships operating alone from attempting close engagements with surfaced submarines unless they had first used their onboard aircraft to destroy or disable all enemy anti-aircraft batteries.
Not unexpectedly, the U-boat’s crew was celebrated upon returning to Germany. The engagement was also featured in a late 1942 article in the Wehrmacht propaganda magazine Signal, titled “We destroy an enemy zeppelin”. In fairness, the U-boat captain’s belief that the attacking airship was destroyed was reasonable, given his perspective. However, as was typical for Signal, the propagandist went further and drew a number of strategic conclusions intended to demonstrate the desperate situation faced by the Allied anti-submarine campaign. Among these was an inference that the “destroyed” airship may have in fact been the former Graf Zeppelin leading to the implication that the Americans were driven to use such “flimsy” civil craft in naval patrols because of excessive naval losses in the Battle of the Atlantic and Pacific theatre. The article also contains the only known photographs of an American airship taken from the enemy perspective. One image of Sacramento drifting bow down barely 200 feet off the surface of the sea, dropping “debris and fuel” (actually ballast), smoking from one engine car, and clearly missing most of its control gondola is particularly striking (See appendix I for the complete text of this article).
Airships were not tested in air-to-air combat, another area in which they were presumed to be vulnerable. They never encountered Luftwaffe fighters or other well-armed combat machines. On rare occasions in the 1941-42 period, US airships operating in the eastern Atlantic came within visual range of lumbering Fw 200 Condor reconnaissance-bombers or the odd long-range German flying boat. US airships typically carried multiple .50 cal machine guns in the control car and on stations dispersed along the hull or in engine cars to discourage air attack. However, German patrol bombers never sought to engage US airships, probably because they themselves were weakly armored, poorly armed, and operating at the limit of their endurance when the contacts were made.
On three reported occasions US airships launched F3A fighters to drive away German aircraft, although the enemy planes were not destroyed. In one of these instances a fighter from USS Intrepid was severely damaged and had to ditch, its pilot being picked up by the airship.
One advantage of the ZRCVs was unexpected. As the war progressed and German submarines began to make greater use of search and anti-air radars, it became apparent that the giant airships, so visible to the naked eye, were less so to the radars of the day. Their diffuse aluminum structures and fabric envelopes tended to present a confusing radar signature completely unlike that of either airplanes or surface ships. Until this was understood, German radar operators frequently misinterpreted radar contacts with airships as flocks of seabirds or signal anomalies rather than potentially hostile warcraft.
It cannot be denied that the airships also had inherent flaws that could have been anticipated by anyone who participated in the peacetime fleet exercises of the late 1930’s.
In general, the reliability of visual sighting from the airships and their planes did not live up to the optimistic claims made by their supporters in the 1920’s and 1930’s. In good visibility, a giant airship typically operating at less than 4000 feet is far more visible to its enemy than the other way around, especially when the target is a small submarine. Prior to the widespread use of radar on the airships, German submarine commanders frequently noted with amazement how apparently close a US airship could cruise by without seeing their surfaced ship.
Similar problems affected visual scouting from the airships’ planes. Unlike their land- and carrier-based counterparts, which were often radar-equipped two-seaters, most airship-based scout planes rarely carried a dedicated observer or search radar. To make them even lighter, airship planes often had less fuel capacity. Since most of them did not have conventional landing gear, they could not land on aircraft carriers or at land bases, meaning they had to remain close to their parent craft.
Because of the above factors, HTA unit operating doctrine tended to be conservative and risk-averse. Only in general patrol, when the planes and airship followed preset courses and speeds to cover large expanses of sea, were airplanes operated far beyond the range from which they could see the airship. In most attack situations, when the airship was required to change course and speed to track a submerged submarine, attack aircraft were usually not launched until the airship itself was in visual range of the target.
The early impression that airships were vulnerable to weather conditions was also borne out by wartime experience. While airships were really not any more vulnerable to violent weather than airplanes, 1940’s era aircraft could operate at speeds and ceilings allowing them to avoid or limit their exposure to the worst conditions. Airships, on the other hand, could neither rise above a rapidly moving Atlantic storm front nor outrun it. Once in a significant storm, the airship was at the mercy of winds exceeding its maximum speed and sudden pressure changes that affected its bouyancy. Even the mere risk of strong weather often curtailed airship operations when fast-moving or high-flying airplanes could perform theirs. Two airships, USS Newark and USS Tulsa, were lost at sea with all hands as a direct result of violent weather. The loss of Newark was particularly tragic in that it occurred on May 7, 1945, after Allied victory in the European theatre.
Ground handling also remained a major Achilles’ heel of the rigid airship. In the best conditions and with mechanized assistance, landing and launching large airships was an involved process that required large ground crews. Even relatively mild winds at airship bases could delay or cancel what would otherwise be routine sorties or landings. This created the legitimate impression among many in the fleet that the airships were undependable and difficult to base when compared with other aircraft or surface ships.
The risk inherent in airship landing operations is best exemplified by an August, 1943 accident at Ceiba NAS in Puerto Rico which almost destroyed USS Honolulu. Just after completing a week-long ASW search Honolulu encountered deteriorating weather. Her commander elected to temporarily shelter the airship at Ceiba rather than continue on toward Norfolk or Pensacola. Suspecting that conditions would only worsen, he attempted the landing in unsettled conditions, with gusty winds and blowing light rain buffeting the air station. Initial ground crew operations were uneventful. The landing crews had secured the ship’s nose cone to the movable mast and were preparing to anchor the lower fin to the aft mooring out rails when the ship was hit broadside by a sudden and unexpectedly forceful gust of wind. Because many of the ground crew had loosened their hold on the mooring lines, the remaining men attending the aft fin immediately lost control of the ship and the incompletely secured fin was ripped from its moorings.
Honolulu immediately began to vane, dragging the fin around the circle. After the ship finally came to rest parallel with the prevailing winds the lower fin was virtually destroyed, and the overall integrity of the ship’s structure was in question. The airship was eventually brought safely into the hangar, but it was clearly in no condition to risk a return flight to Lakehurst once the weather cleared. The Navy initially considered writing the ship off as a total loss but eventually decided to attempt repairs in the Ceiba hangar, a task for which the hangar was unsuited. Goodyear design and construction staff together with specialized jigs and tools needed to be brought in. Repairs required the aft end of the ship from frame 3 to be reconstructed. Not only did this eliminate the hangar’s use for other ZRCVs, ZNP-14, a non-rigid airship patrol squadron normally based at Ceiba, lost use of the hanger and was disbanded, essentially eliminating the base as a functioning ASW facility for over six months.
The Pacific
As noted, the Navy initially saw no reason to deploy combat airships to the Pacific. Unlike the Atlantic theatre, where the Allies generally enjoyed control of the air, Japan had an extremely effective naval air arm and a history of using it very aggressively. The Navy believed that rigid airships would be extremely vulnerable to Japanese carrier aviation if operated in any active combat zones of the western Pacific. Extensive use of floatplane fighters and the very long range of many Japanese aircraft also added to the Navy’s hesitance to risk its costly airships in the Pacific. Finally, even though Japan had a large and capable submarine fleet, Japanese submarine doctrine virtually ignored commerce raiding. Only rarely did Japanese submarines operate off the US Coast. There was thus little need for the ZRCV or ZRS ships airships as convoy escorts or ASW hunter-killers. The other prime role for airships was air-sea rescue and harbor patrol flights, task that could be adequately handled by blimps, Catalina flying boats, or the two ZRN training ships at Sunnyvale.
However, in early 1944, after the Japanese carrier fleet had been largely eliminated and the worst of the German U-boat threat in the Atlantic had apparently passed, the oldest ZRS ship, USS Akron, was unexpectedly detailed to the Pacific Fleet and flown to a temporary mast erected at Kanoehe Naval Air Station in Oahu, Hawaii.
The rationale for this deployment has never been fully explained. Not only was there was little need for Akron’s services in Hawaii this late in the war, the ZRS ships were far less suitable for Pacific duty than the larger ZRCVs. Politics was almost certainly the reason for this strange deployment
USS Akron was commanded by a young officer from an influential New England family with strong connections in the Democratic Party. In two previous years, Akron had amassed an excellent operational record, but this was less visible than the sinkings of U-boats reported by the more capable ZRCV-class ships. It was perhaps thought by some that Akron (and its undeniably capable 27 year old commander) might have more opportunity for public acclaim if it was the only ship of its type in the theatre.
As events transpired, this is exactly what occurred. Akron capably provided ASW scouting and air/sea rescue activities between Hawaii, the Marshall Islands - and farther west as the Japanese Empire shrank. Then she moved on to Guam.
Finally just a few days before the end of the Pacific War, Akron accidentally stumbled on over 700 survivors of the cruiser USS Indianapolis only hours after she had been torpedoed and sunk by a Japanese submarine south of Okinawa. In addition to pulling over 200 severely injured men from the water herself, she dropped life rafts, water, and rations to the remainder and kept station for two days over the survivors until surface ships arrived to complete the rescue. Of the approximately 700 men in the water, all but 35 were successfully rescued by Akron and other ships arriving on the scene. The airship’s machine gunners were also kept busy shooting sharks that started to appear shortly after Akron arrived.
Several days following the rescue of the Indianapolis survivors, Akron reported a surfaced submarine off Luzon This submarine was eventually attacked and sunk by aircraft from the aircraft carrier USS Essex. Postwar research in Japanese archives would indicate that the victim was I-58, which several days previously had radioed a report that it has sunk an “Idaho-class battleship”. Since no US battleship was sunk but the large and similar-looking Indianapolis was, there is little doubt Akron was both savior and executioner – a story of military fortune worth more than its weight in gold in 1960. After the war and later into his successful Presidential campaign, photos of the photogenic young airship commander directing rescue operations and shooting at sharks with a .50 cal. machine gun from a lowered cloud car virtually ensured the election of John Kennedy as the 35th President of the United States
ZRS Ships at War
In most respects, the early style ZRS-class ships (USS Akron, USS Macon, USS Wichita) were too old to be truly effective in the Battle of the Atlantic. Their airplane hangars, which had been designed around the smallest fighters available in the early 1930’s, could only handle 3 unarmed Seafin scouts, giving the ships no offensive capability other than a small number of 325 lb depth bombs carried beneath the control car.
Nonetheless, the ships did provide valuable aerial coverage for convoys crossing the Atlantic. As the war progressed and their military value declined further, they were primarily used in the long-range air/sea rescue role. Being the only craft which could loiter safely for days in U-boar-infested waters to search for and pick up survivors without needing to alight on the water, and because the ships could, if necessary, rescue nearly two hundred survivors by themselves, the ZRS ships literally saved thousands of men who otherwise may have drowned or died from hypothermia.
All three old ZRS ships were immediately retired from service upon the conclusion of the war, and scrapped shortly thereafter. The newer and more modern USS Newark was lost in a violent squall off the coast of Virginia on May 7, 1945 with all hands. USS Belleau Wood, the former Graf Zeppelin, was deflated and kept in mothballs while the Navy attempted to find a civilian buyer willing to refit her as a passenger or cargo ship. But, by this time the capabilities of airplanes had reached the point that there were no takers. She was eventually donated to the Smithsonian Institution in 1951, dismantled, and placed in storage Lakehurst Hangar No.1.
ZRCV Ships at War
US Navy wartime records claim the destruction of 34 U-boats solely by ZRCV airships or their HTA units. These documents also show that airships assisted in the sinking of another 75 submarines by surface units or conventional aircraft. Twice during the war, ZRCV ships operating alone were able to accept the surrender of damaged U-boats. On only three instances did submarines successfully attack convoys escorted by ZRCVs, and in each case, the U-boats were in turn sunk by the airship or other units operating in concert with them.
It must be acknowledged that the above destruction figures cannot be accepted at face value. Confirmations of submerged submarine kills are very difficult. Unless a submarine is forced to the surface, there is usually no clear evidence the ship has in fact been destroyed. Submarines frequently release oil slicks, clothing, small equipment and other debris as a decoy when under attack, so observation of debris cannot be taken as proof of a submarine’s destruction when it bottoms and can no longer be detected by sonar or hydrophones. Even when the submarine is in fact sunk, it is then virtually impossible to determine who actually delivered the killing blow when multiple ships or aircraft were involved.
Postwar review of surviving German records show that at least 10 U-boats reported as sunk by ZRCVs operating alone returned to their bases in France or Germany. Several other submarines claimed as “partial kills” by airships operating in concert with surface ships also made it home. Thus, it would appear that the airships probably accounted for only a small handful of U-boats claimed by allied forces in the Second World War.
However, the value of a weapons system can also be measured by its success in preventing the enemy from achieving his goals. In this regard there is no denying the effectiveness of the ZRCV airship as an anti-submarine weapon. ZRCV’s were at their best when stalking and attacking submerged submarines once contact was made. Submarines operating at or around periscope/snorkel depth could be relatively easily seen by the low flying airships. Once the target was observed, the airships could drop passive or active sonar buoys into the water while at the same time remaining effectively invisible to the submarine’s hydrophones or sonar. The airships could stay on station for up to a week in some instances and could stalk and harass submerged submarines well beyond the ability of the submarines to stay below the surface.
While there are occasions recorded in both US Navy and German records of a particularly skilled U-boat commander evading a determined ZRCV attack, these situations were few and far between. More typical is this report by KM Kapitanleutnant Heinrich Zimmer, who surrendered his damaged U-554 to the ZRCV USS Manila Bay on March 12, 1945:
"We were returning from patrol off the coast of Brazil when, at 0900, we saw two small planes heading toward us at long range. We initially believed these to be Brazilians based at Belem. I submerged to a depth of 60 meters and our ship survived several poorly aimed depth bombs, presumably dropped by the aircraft. I set a due easterly course at 6 kts and remained submerged for about 20 km. When the attacks were not repeated, I brought the ship to periscope depth and immediately observed an American zeppelin at low altitude to our SSW, approximately sixteen thousand meters distant. It appeared to be heading on a southwesterly course. Believing that the airship probably did not see us, I ordered a dive to 60 m followed by a turn to the NNE to put as much distance between ourselves and the zeppelin. We were not attacked.
"We maintained this course for approximately 100 km, at which point I surfaced the ship to replenish the batteries and take bearings. It was now 0300 on the following day and there was a full moon out. We had no trouble spotting the enemy zeppelin loitering stationary about 10 km to north of us. I maintained an easterly course on the surface, hoping that we had not been seen, but we soon came under attack by a single American attack plane we assumed was from the zeppelin. I again dove the ship, this time to 120 m. We detected several distant depth bomb explosions. By now our remaining battery power was becoming critically low. It was obvious we would not shake our pursuer, so I determined to surface and do my best to engage the zeppelin and its planes, and hopefully drive it off. We surfaced at 1000 and within minutes came under attack from three airplanes who strafed the ship with machine guns and rockets.
"We succeeded in destroying one plane and driving off the others, but all topside guns were eventually destroyed and we began taking on water. I then ordered a crash dive and emergency release of oil and decoys, hoping the Americans would believe they had sunk us. We could not bottom but ceased cavitations and maintained a stationary depth at 45 m until our oxygen virtually ran out, at which time we blew tanks and surfaced. As I feared, the enemy zeppelin was still on station. The huge ship flew right over us and dropped a few small bombs of its own, which damaged the ship’s starboard dive plane and further increased our flooding. As neither crew nor ship was in any condition to fight or flee, we signaled our desire to surrender, which the American accepted. Although I intended to scuttle U-554 once everyone was off, several armed American sailors rappelled down from the airship and took command of the bridge while the ship was still being abandoned. One German-speaking sailor let me know in no uncertain terms that his fellows on the zeppelin would murder me and my crew if the submarine was scuttled – so I didn’t even attempt it. We all knew the war was effectively over and I saw no reason to pretend otherwise. After I and all other officers were taken on board the zeppelin, and all of the crew were set adrift in life rafts, a small American prize crew took command of the ship. After about six hours an American destroyer arrived on the scene, picked up my crew and took U-554 in tow." (US Naval Archives, VIII-78c)
What Kapitanleutnant Zimmer does not report is the fact that repaired and restored, U-554 is now on display at the US Naval Airship Memorial Museum at Lakehurst Naval Air Station.
Postwar Developments
The naval airship program came close to being eliminated in the immediate years following the Second World War. The ZRS and ZRN type ships were removed from service and scrapped shortly following the end of the war, and all airship bases other than Lakehurst were closed. However, the developing Cold War gave the reduced program a temporary new lease on life.
All surviving ZRCVs were refurbished at outfitted for dedicated ASW work. Based on wartime experience, which tended to show that the hook-on aircraft had planes had minimal utility for reconnaissance or scouting, the ships’ compliment of planes was reduced to only three advanced ASW-optimized Harriers. This weight saving allowed for the ships to be fitted with a host of sonar and radar systems as well as several new and experimental missile and ASROC systems. The ZRCVs remained in service in this capacity through the mid-1960’s when they were finally supplanted by traditional escort carriers, helicopter-carrying destroyers, and frigates.
Nonetheless, both Goodyear-Zeppelin and the Navy’s lighter-than-air bureau proposed several follow-on ZRCV designs, arguing that the large rigid airship could still fill a combination of ASW and attack roles more efficiently than surface ships. As concern over the rapidly expanding Soviet submarine force increased during the 1950’s and 1960’several design studies for updated ZRCV’s were proposed. These ranged from a resurrection of the stillborn ZRCV-11 design of 1941-42, to the gigantic 18,000,000 cubic foot nuclear powered ship (ZRCVN) carrying both fixed- and rotary-winged aircraft. None of these designs ever saw fruition.
However, the large military airship was not quite dead. As a follow-on program, the Department of Defense ordered two large experimental airships which featured radical innovations such as nuclear power, advanced boundary layer control, artificial superheat to improve static lift, increased use of dynamic lift, simplified command and control systems, and other refinements. It was initially hoped these experiments would lead to a fleet of advanced early warning and air control ships, similar in concept to later AWACS aircraft. Two flying prototypes, ZRW-1 and ZMCW-1, were constructed. Rather than being operational units, they were purely flying test beds to evaluate a number of these advanced technologies in various combinations. Although their designations mirrored naval practice and they were operated for the most part by naval personnel, neither airship was a commissioned ship in the US Navy, nor was either of them named. Had they led to a series of operational units, it is believed they would probably have been operated by the US Air Force.
ZRW-1 This was the first and by far the most conservative design of the two. It featured a fairly traditional “zeppelin” structure and was completed in 1962. However, with a volume of 12,000,000 cubic feet and a length of 1015 feet ZRW-1 remains the largest airship ever built. It included a large internal bay for the AEW radar systems, communication systems, and required personnel. A second internal structure was provided near the center of the ship for a test nuclear reactor, which was fitted in 1963. The reactor was largely unshielded, protection for the crew being provided by the sheer distance (400 feet) between it and the nearest regular crew stations. The ship was equipped with a system of internal steam heating coils to provide artificial superheat to the gas cells and regulate lift. The system was also designed so that heating to each cell could be adjusted to experiment with variable heating as a means of changing attitude and trim, rather than the wasteful practice of ballast and gas release. The test reactor was used to heat the steam for the superheating system and provide electricity for the radar and communications suite, but did not power the engines. These were contained in four conventional engine cars. The ship was supplied with a single trapeze and landing station for skyhook-equipped aircraft, but did not carry its own planes.
ZMCW-1 This ship was intended to be a much more radical experiment. Her final design was not completed until after ZRW-1 had been flying so some lessons could be derived from experience with the earlier ship. ZMCW-1 was completed in 1964. Its greatest innovation was in its basic structure, which replaced the heavy and redundant zeppelin design with a stressed thin aluminum alloy skin over a very light structural framework. This system was actually quite old, having been originally utilized in the small “metal clad” naval airship ZMC-1, which operated successfully throughout the 1930’s. Although sometimes considered a “blimp”, the ZMC-1 was actually a rigid airship because its stressed skin hull could maintain its shape without internal gas pressure up to approximately 20 kts. At higher speeds, positive gas pressure within the hull was created by use of ballonets. Although the BuAer made several proposals for large ships using metal-clad principles in the 1930’s, none were pursued.
As completed, ZMCW-1 was somewhat of a hybrid, having significantly more internal structure and compartments than a pure metal-clad would. It contained slightly over 8,000,000 cubic feet of helium in six large cells, each with its own internal pressure ballonet. A separate system was used to regulate air pressure within the overall envelope. The metal hull could maintain its shape at all but the highest speeds, at which point positive pressure needed to be provided. The AEW radars were mounted within the center of the 2nd gas cell, connecting to the control gondola directly below. An unshielded nuclear reactor was placed within cell No 5, near the ship’s midsection. The reactor provided power to a steam/electric engine driving a large propeller at the stern, and to four smaller electric drive engines powering variable tilt propellers mounted along the sides of the ship. The reactor also provided gas superheat in the same manner as in ZRW-1. As opposed to all other airships, ZMCW-1 was designed to be operated in a slightly “heavy” state, with positive lift provided by the 4 large steering propellers aligned in a downward direction and/or dynamic flight provided by forward speed. In an emergency, it was calculated that sufficient neutral buoyancy would be provided by the artificial superheat. What this all meant, however, was that ZMCW-1 needed power to remain aloft, and that this power all came from a single source, the central nuclear reactor.
The other radical innovation of the ZMCW-1 involved command and control improvements, together with a concomitant reduction in crew size. The ship could be piloted by a single crewman, who controlled speed, course, and altitude from a single set of controls. Other crew stations monitored and controlled superheat, pressurization, ballast, the radar suite, and the overall operation of the nuclear plant. Thus, whereas the ZRW-1 and all other rigid airships required telegraph communications between the bridge and crew stations throughout the ship, the ZMCW-1 could be effectively flown by fewer than 10 men, all clustered together in the control gondola. ZMCW-1 was provided a single trapeze below the control car for a single plane, but like ZRW-1, it did not carry its own aircraft.
When ZMCW-1 entered flight testing in the summer of 1964, she was almost universally seen as the most sophisticated airship ever to fly. Most of her radical systems worked far better than had been anticipated, and the Department of Defense was prepared to order a series of AEW airships based on the design.
Then disaster struck. On an electronics test flight off Florida on August 12, 1965, pressure controls in ballonet No 1 at the bow of the ship malfunctioned during a routine pressure adjustment, leading to critical positive overpressure. The ship was hovered, and the problem resolved in time to avoid a disastrous explosion of the bow gas cell. However, when standard operating pressure was restored, it became apparent that the localized overpressure had compromised the structural integrity of the stressed-skin hull to the point that it could no longer maintain its shape. When an attempt was made to resume forward motion, the hull began to crumple inward, placing the internal gas cells in jeopardy. Since the ship could no longer proceed in a forward motion, the rear propeller was reversed. However, the ship was difficult to control in this direction, and it began a series of undulating altitude changes, which further stressed the damaged hull. As a result of damage to the fore gas cell and hull she was also losing helium and altitude. Finally, assisted by favorable winds as much as by her own power, the ship crossed the coast near Daytona. At this point, it was obvious a forced landing would be necessary. Her crew shut down the nuclear power plant and prepared for landfall. Drifting tail-first, ZMCW-1 glanced into the beach, ripping apart her lower fin and stern gas cell. She then slid along for almost a mile, and finally came to rest, her hull ripped apart and crumpled into an almost unrecognizable shape. The ship was a total loss. Out of the twelve men on board, all survived. Luckily, as designed, the reactor capsule remained intact. In some respects, even this disaster proved the advantages of some of ZMCW-1’s design concepts. The self-contained control gondola with its small crew probably helped save lives and all safety mechanisms associated with the nuclear reactor worked flawlessly. However, none of this made up for images of a multi-million dollar airship crumpled on the Florida coast like a rotten, beached silver whale.
Following the loss of ZMCW-1, the Department of Defense lost all interest in pursing similarly designed airships – and for all intents and purposes – airships in general. The remaining ZRCVs had already been retired and ZRW-1 (with its nuclear power plant and AEW systems removed) was offered for sale to private bidders. But by 1965, there had not been a commercial airship in service in 20 years, and there were no takers. The ship was scrapped in March, 1966.
The Final Acts
All of the retired ZRCVs were finally scrapped during in 1969, except for USS Bon Homme Richard, which was transferred to the United States Coast Guard, who operated her intermittently in the air/sea search and rescue role for two years. Her ASW equipment was removed and she carried 3Super Goose flying boats. She was never formally commissioned as a ship in the Coast Guard, and was only referred to by her Coast Guard designation CGZ-1. In this guise, she was painted in the traditional white Coast Guard livery, with the diagonal red stripe and Coast Guard insignia on her forward hull. She was never particularly popular with “front line” Coast Guard stations, who considered her a fair weather craft forced on the service by the Department of Defense and Navy Reserve. She spent most of her time on public relations and recruiting tours on the Atlantic and Gulf Coast. She was finally retired and scrapped in 1972.
Although the last rigid airship flew in 1971, the Belleau Wood/Graf Zeppelin still survived as a partially dismantled structure occupying space in the old Hangar No. 1 at the Lakehurst Naval Air Station. In 1980, after a survey of the ship’s rings and longitudinal girders showed the hull retained enough integrity to permit eventual reconstruction, the airship’s framework and Hangar No. 1 were placed on the National Register of Historic Places as unique technological reminders of the rigid airship era. Popular interest in preserving the airship was further stimulated by several Navy proposals in the late 1980’s and early 1990’s to demolish the hangar at Lakehurst (and by implication the airship framework) to make way for training facilities.
As early as 1976, airship enthusiasts on both sides of the Atlantic had already been lobbying for her reconstruction and preservation as a museum ship, and the threats of demolition gave them further ammunition. Several lawsuits and injunctions in the 1990’s prevented demolition of the hangar and the airship’s structure. In 1995, the German government entered the controversy and became an active advocate for the airship’s preservation. Finally, on November 3, 1998, President Clinton and Chancellor Helmut Schroeder signed an agreement in Washington pledging their respective governments to preserve the zeppelin, and share equally in the funding of a project to reconstruct it for static display, should a suitable location be found.
Today, together with the reconstructed and relocated Lakehurst Hanger No 1, the 803 foot-long airship is the centerpiece of the huge Lighter than Air Exhibit at the Smithsonian’s National Air and Space Museum (NASM) Annex at Dulles International Airport. As requested by the German government, the ship has been reconstructed inside and out as the civil Graf Zeppelin. At Germany’s insistence, she does not sport huge swastika flags on her fins. Many people, such as various Jewish-American and human rights groups, supported this. However NASM staff and others in the preservation community strongly advocated for the swastikas as necessary to present the ship in an historically accurate context. For a while, it appeared that this controversy could even derail the whole restoration project. Eventually, however, a compromise was reached eliminating the Nazi flags from the ship, but allowing accurate Nazi emblems on all photographs, travel posters, brochures, tableware, crew uniforms, and other small items accompanying the airship’s exhibit, providing that no replica items offered for sale in the museum’s gift shops contained swastikas or other Nazi emblems.
Graf Zeppelin’s gas cells are occasionally inflated with an inert mixture of nitrogen and helium to check for rips and tears in the goldbeaters’ skin, but normally the airship is maintained in a non-inflated state. She hangs beside a 1/10 cutaway scale model (still almost 100 feet long) depicting her in her wartime US Navy guise. Several restored hook-on aircraft ranging from one of USS Akron’s original F9C Sparrowhawks to a post-war ASW Harrier are also part of the exhibit. All internal passenger spaces have been painstakingly replicated as they would have appeared in 1939. Open for public tours during the museum’s regular hours, and also available for special events and dinners, she is the single most popular exhibit in the entire Smithsonian collection.
From time to time, representatives in Congress or the German Bundestag put forward resolutions that the airship be refitted for flight. Following standard NASM practice, the restoration of her engines, control systems, and structure was sufficiently thorough that she probably could be flown with minimal additional work.
However, this is strongly rejected by historic preservationists and aviation safety experts on both sides of the Atlantic. In the airship’s current restored condition, she completely lacks modern avionics and safety systems required for FAA approval, and the installation of such equipment would impair her historic integrity as a museum exhibit. Even if she could be flown, there are no longer enough people still alive with the training to safely operate her in the air or handle her on the ground, making any attempt to fly her incredibly risky.
Times have changed. Technologies have changed. It is remotely possible that Graf Zeppelin could be inflated with full helium during a routine gas cell check and allowed to “float” at neutral buoyancy in within its display hangar, but she will never ply the open skies again. Nor will any other zeppelin airship.
The US Civil Airship Program – Missed Opportunities and Bad Timing
Any history of the successful US Naval Airship Program is incomplete without at least some discussion of the parallel civilian program undertaken by the United States in the 1930’s. As has been noted, by the mid-1920’s the United States was well-placed to take the lead in the civil application of airship technology. The US had the world’s only commercially extractable sources of non-flammable helium lifting gas. Goodyear’s 1923 joint venture with the Zeppelin Company gave the nascent US airship industry access to all the knowledge, technical expertise, and patents of the acknowledged German experts in the field. The 1928 Airship Act gave the rigid airship favored status in US overseas commerce, and subsequent amendments together with generous WPA funding in the 1930’s provided ample money to support the construction of commercial airships, airship hangars, and other support industries.
Initially, the Goodyear-Zeppelin airline venture looked like a success. Two separate US flag carriers were chartered in 1930: the American Zeppelin Transport Company (AZTC) to handle international flights to Canada and Latin America, and the Pacific Zeppelin Transport Company (PZTC) to link the continental USA with Hawaii, Australia, and the Far East. Through the auspices of the Goodyear-Zeppelin partnership, the US routes were merged with those flown by the first Graf Zeppelin (LZ-127) between Europe, North America, and South America to create a globe-spanning network. In 1931, the operations of the US and German airline operations were combined, and the old Graf spent one year assigned to the PZTC, carrying paying passengers while pioneering commercial routes from Sunnyvale NAS to Tokyo, Manila, and Sydney.
In 1930, LZ-128 was laid down by the Zeppelin Company in Friedrichshafen specifically for use by Zeppelin’s American partners. With a gas volume of slightly over 7,000,000 cubic feet, she was a slightly smaller prototype of the later LZ-129 Hindenburg, with an internal passenger bay, individual staterooms, and public areas capable of handling up to 55 passengers and freight. In 1932, her maiden voyage took her to Akron, Ohio, where she was commissioned ZS Spirit of America and entered service on PZTC’s California-Hawaii route. In 1931, Goodyear-Zeppelin ordered its first three US-built civil airships, based closely on the firm’s parallel ZRS-4 design (USS Akron). Late in these ships’ design, an extra bay was added, making them slightly larger than Spirit of America.
The first American ship, ZS Columbia, was completed in early 1934, and her sister, ZS Pacific Star, took to the air later that year. As detailed elsewhere, completion of the third ship of the class was delayed by labor stoppages, and when she emerged in 1937, it was as the navy’s ZRS-6, USS Wichita.
ZS Columbia was initially employed on AZTC’s South American route, and ZS Pacific Star, as her name implies, was used solely on extended routes linking Hawaii to Manila, Tokyo, and Sydney. Although both ships never lacked for paying passengers, they were never wholly satisfactory as passenger liners. Following standard late 1930’s practice, passenger spaces were housed in the hull, occupying areas that would have been devoted to airplane hangars in military versions of the design. Double berth interior cabins were provided for up to 45 passengers, with surprisingly small and Spartan public areas on either side serving as lounge/dining rooms.
A major problem was the interior location of the ships’ eight engine rooms – a trait inherited from the basic ZRS design. When operating at full power, these engines imparted noticeable vibration to the passenger areas, and were also noisier than the exterior power cars used on German zeppelins. Passengers who had the opportunity to travel on German ships such as Hindenburg invariably commented on how less comfortable and less luxurious the American liners were.
Goodyear-Zeppelin soon recognized these faults, and the next series of three commercial ships laid down in 1935 were in many ways enlarged versions of the Zeppelin Company’s sucessful Hindenburg design. The ships reverted to standard zeppelin design practice with a strong lower keel and four exterior power cars. They also reverted to even older zeppelin practice by placing first-class passenger cabins in an elongated external control car, giving these passengers an outstanding exterior view from their cabins. As designed, they would have contained over almost 10,000,000 cubic feet of helium, making them in size, if not detail design, the commercial equivalents of the naval ZRCV ships. They would have been named after US Presidents: ZS George Washington, ZS Abraham Lincoln, and ZS Theodore Roosevelt. None of these ships were completed, however, first falling victim to the gradual demise of the Goodyear-Zeppelin partnership, and finally to the Second World War. Goodyear briefly sought to resurrect these designs in the late 1940’s, but by then the era of commercial passenger zeppelins had passed.
By late 1935 diplomatic relations between the United States and Hitler’s Germany were becoming strained. Although the Goodyear-Zeppelin partnership still existed on paper, the operation of the joint airline service was disbanded when the Nazi government nationalized the Zeppelin Company’s airline operations under the Deutsche Zeppelin Reederei. In the US, the original Graf Zeppelin and the new Hindenburg became increasingly visible symbols of the unpopular Nazi regime, emblazoned as they were with gigantic Nazi flags. Increasingly, Goodyear’s association with the German airship industry made the firm unpopular among many Americans concerned about the direction in which the Nazis appeared to be leading Germany and the world. This reached its low point during the strike of 1937, when Goodyear’s tires were routinely referred to as “Hitler Doughnuts” by labor representatives.
However, the final dissolution of Goodyear-Zeppelin’s commercial venture came from Germany itself. The Zeppelin Company’s Director, Hugo Eckener, a long-time opponent of the Nazi movement, was eventually pushed out of his positions at both Zeppelin and the Deutsch Zeppelin Reederei in 1937 by the Nazi Party. While the full details of what then transpired may never be known, it would appear he and several others in the Zeppelin organization hatched a scheme to commandeer the Hindenburg while en route to the USA during its initial crossing of 1938 and either defect with the ship to the USA, or failing that, destroy it as part of a highly visible anti-Nazi protest while on American soil. What is known is that the Hindenburg did turn back to Germany while over the Atlantic, the only time a commercial zeppelin never completed a regularly scheduled crossing in 12 years of operation. It is also known that Eckener and 13 other Zeppelin employees were immediately arrested upon their return to Germany and imprisoned at Dachau on May 6, 1938. All but one of the conspirators, including Dr. Eckener, eventually died in the concentration camp.
Not unexpectedly, the Nazis accused the US of complicity in this plot, claiming that several US naval officers and Goodyear-Zeppelin employees attached to the Lakehurst Air Dock knew of Eckener’s plans. In retaliation, the Nazi government liquidated the Goodyear-Zeppelin partnership in Germany and suspended all zeppelin flights to the USA for the remainder of the 1938 season. Ironically, when transatlantic flights were resumed by Hindenburg, the new LZ-130 Graf Zeppelin, and LZ-131 Deutschland in 1939, the new Graf Zeppelin found itself in the USA at the outbreak of the European War, and, as related elsewhere in this paper, was interned and in 1940 sold to the US Navy in a short-lived wartime propaganda coup for the Nazi government.
Also, throughout the 1930’s the capabilities of airplanes increased significantly to the point that, by 1939, several of Boeing’s new Clipper Ship flying boats could provide better and more flexible commercial capabilities in trans-Atlantic and trans-Pacific travel than the two PZTC airships, ZS Spirit of America and ZS Pacific Star. This was even truer for AZTC’s ZS Columbia’s route through the Caribbean to Brazil. When 1940 diplomatic difficulties with Japan closed the Tokyo route, this also led to the abandonment of the Manila and Sydney runs, which by themselves were insufficiently lucrative to support regularly scheduled passenger service. In early 1941, both the PZTC and AZTC were reoriented as charter lines, with their airships increasingly used to transport bulk freight and military personnel rather than civilian passengers. Spirit of America was relegated to occasional marketing flights and special cruises along the Pacific coast.
With the outbreak of the Pacific War, all three ships were commandeered by the Navy and used to haul high volume cargo and key personnel to Hawaii. Spirit of America was damaged in a mooring accident at Sunnyvale in August, 1942, and sold for scrap later that year. Columbia and Pacific Star continued in service until early 1944, when they were also scrapped to make room for aircraft maintenance facilities in their California hangars. The retired, original, LZ-127 Graf Zeppelin, together with the Deutschland and Hindenburg, met a similar fate in Germany, marking an ignominious end to what started out as a grand experiment in international cooperation and luxurious aviation travel.
Every so often there are those who push for the resurrection of zeppelin airships as luxury aerial cruise ships for the rich or specialized heavy-lift vehicles. As much as these plans sound attractive to the general public, especially those who remember the exploits of the US Navy’s wartime zeppelins or the luxurious German civilian liners, they eventually run aground when looked at in the harsh light of economic reality. Luckily, we do have one surviving airship, and anyone who wishes can experience what airship travel was like for free by visiting the delightful Graf Zeppelin exhibit at NASM.
Auxiliary and Support Vessels
A number of proposals were made in the immediate prewar years for support vessels capable of tending and basing ZRS and ZRCV type airships on remote stations. Although there had been some early airship landing experiments with the carriers USS Saratoga and USS Ranger, and several fleet oilers had been provided a high masts to serve as experimental airship tenders in the 1920-1940 period, these did not provide a satisfactory solution. The only feasible early option was to erect temporary masts at advance bases. Such masts were widely used, but the airship was completely open to the effects of atmospheric cooling, solar heating, wind gusts, and other weather events. Because this required the airship’s crew to constantly monitor and adjust to changing conditions, stationing ships at temporary facilities for more than a few days was discouraged. Only hangars provided the security necessary to base airships for an extended period.
With the outbreak of the Second World War, most large airship hangar facilities overseas were either occupied by Axis powers or within easy range of enemy land-based or naval aviation. Further, the ZRCV ships were so large that they could not be permanently stationed at any land-based airdock other than those built for this purpose in the continental United States.
In 1942, BuAer offered several proposals for large sea-based platforms capable of servicing and sheltering large rigid airships. Three alternative design schemes were proposed and studied.
The most simple solution was not actually a vessel, but comprised a hangar facility erected on a series of massive floating platforms, not unlike the pontoons used by army engineers to erect temporary bridges. Rather than sailing to the remote bay or cove, the hangar would be assembled there. This was by far the least expensive approach, but had no other advantages. Complete maintenance of airships would still have required substantial land-based facilities. The concept was rejected by the Navy outright.
The Auxiliary Airship Dock proposal (AZD) envisaged a large, unpowered barge-like vessel that would be towed and anchored in its intended location. The AZD was far superior to the pontoon design because it offered useful hull space to contain all supplies and materials necessary to maintain an airship and its aircraft on remote station. However, the Navy perceived that towing a massive barge hangar over 1000 feet long across several thousand miles of open sea had many obvious and potential risks. In addition, while the AZD could service and maintain its airship, it would require its own tenders and tugs to maneuver, and these ships would need their own support facilities. The AZD concept was therefore rejected.
The preferred approach was a self-propelled Airship Tender (AZ). This was a massive self-contained ship featuring a large hangar and mooring out mast occupying over 90% of its overall length. The hangar design itself was very complex, featuring retractable top and collapsible sides. In its massive hull, the AZ carried all that was required to service, repair, and maintain one ZRCV-type airship in addition to machinery and fuel sufficient to steam a one-way distance of 4000 miles at 20 kts. The AZ would be provided with maneuvering screws so it could be rotated to eliminate or minimize crosswinds during mooring operations.
All this required a huge ship, with a far greater displacement, length and beam than an Iowa-class battleship or Midway-class aircraft carrier. Although this design was selected as preferred option, and final designs were developed, the Navy was no position during the Second World War to consider building such gigantic and extremely costly auxiliaries that had no combat capability and could not even transit the Panama Canal. The AZ concept was briefly resurrected in the 1950’s as the Navy assumed a more permanent global presence during the Cold War. New design studies were done, but the decision to retire all the ZRCV’s in 1964 ended any further consideration of a dedicated airship tender in the fleet.
In retrospect, the AZ was a vessel devoid of a real purpose. The Navy never gave any serious consideration to permanently basing airships outside of the US, nor did leadership ever look favorably on making a major investment in huge ships solely dedicated to servicing the relative handful of large airships in service at any one time. Even during their heyday in 1942-45, the ZRCV ships were considered a luxury – a useful luxury, but not a necessary one. The following 1943 congressional testimony from Admiral Ernest J. King regarding the AZ tender sums up the situation well:
“The ZRCV airships we currently have on hand are proving to be extremely useful against the German u-boats. I was always a proponent of these ships and am glad we have them now. However, I do not see us building any more. Regarding the airship tenders you asked about, such vessels would represent a dangerous diversion of resources from what the Navy really needs: more effective combat ships, fleet oilers, and airplanes. Building only one AZ would eliminate one large carrier, three escort carriers or as many as fifteen destroyer escorts from our building program. We need those ships. We do not need the AZ.”
Experiments and Alternate Missions 1939-1944
In addition to their acknowledged ASW role, a number of other uses for rigid airships were proposed and investigated immediately before and during the Second World War. Although basic technological limitations of the airship or military developments eventually rendered these concepts impracticable, they are interesting footnotes in the history of this unusual weapon system.
Stand-off Strategic Bombing As early as 1938, anticipating the possibility that the United States might become involved in a war against Nazi Germany without allies and land bases in Europe or the British Isles, the US Army Air Corps evinced some interest in adapting large ZRCV-type airships as stand-off carriers for their multi-engined bombers. The scheme was strongly opposed by the Navy, who did not want the USAAC intruding into a technology they saw as uniquely naval. However, the Army Air Corps saw this as an interim method of mounting long range or transatlantic bombing missions pending eventual development of planes such as the B-29, B-32, B-35, and B-36. In 1940, when the fall of Britain seemed likely, the Air Corps commissioned a design study from Goodyear-Zeppelin for a 15,000,000 cubic-foot airship capable of carrying, launching and retrieving up to four Boeing B-17D heavy bombers in flight or up to six North American NA-42B (B-25) medium bombers. Goodyear’s calculations showed that operation of four-engine heavy bombers from zeppelin trapeze systems would create unacceptable stresses on the airship’s keel and main frames. However, stripped-down versions of smaller twin-engine bombers such as the B-25 or Douglas DB-7 (A-20) could be modified to operate from airships with minimal penalty. As opposed to the standard ZRCV practice, the airship would lift off empty, the fully fueled and bombed up aircraft then flying to the airships and hooking on for the transatlantic flight. When carrying the aircraft, the airship would fly “heavy”, dependent in part on aerodynamic lift provide by its forward speed and a slight nose-up attitude. The airship would launch its stand-off attack when the intended target was within the bombers’ radius of action (roughly 600-1,000 miles). Just prior to the cancellation of this scheme in 1942, a proposal was floated by the Army to use de Havilland Mosquitoes in the hook-on role. As events proceeded there never was any need to further explore the concept of airships as stand-off strategic bombers. Had the plan been pursued, other problems would almost certainly have been encountered attempting to mate such large, high-performance, heavily loaded, multi-engined craft to the lightly constructed and relatively slow airships.
High Speed/Heavy Lift Transport The relatively short-lived effectiveness of GZ commercial airships as high-speed heavy haulers between the West Coast and Hawaii in 1941/1942, led to a proposal to refit the obsolescent ZRS-class airships (Akron, Macon, Newark, Wichita, as well as the former Graf Zeppelin, as high-speed, long-distance transports for critical equipment and bulk cargo to US bases throughout the western Pacific. The onboard aircraft hangar and aircraft service spaces would be converted to cargo space and all military equipment and stores would be eliminated. However, it was determined that large floatplanes such as the Martin Mars and Hughes-Kaiser HK-1, as well as several large multi-engine landplanes under development for the USAAF, would soon be able to fulfill most of the heavy transport roles planned for the airships, so the scheme was dropped.
Key Personnel Transport. In 1941, the Navy Department seriously considered refitting ZRN-3 Bismarck (the former Graf Zeppelin) as a dedicated long-distance transport for the President, White House staff, or other key civilian and military personnel. The former passenger spaces would be restored, but reconfigured into an efficient combination of offices/conference rooms, communication facilities, and private sleeping quarters. Plans called for the retention of three “perches” for emergency fighter escorts and a courier plane. However, the Roosevelt White House was not keen on the plan, and it was soon realized that the concept would result in a compromise: a craft lacking the speed of traditional transport aircraft such as the C-47 or C-54 or the security and comfort of escorted commercial liners or warships. A plan and cutaway scale model of this proposal can be seen in the Smithsonian’s Lighter-than-Air Exhibit at Dulles International Airport.
Airship HTA Units
With the expansion of the naval airship comand, it became apparent that new aircraft designs needed to be developed for use on airships – designs which explored a variety of fixed or semi-retractable skyhook systems and saved weight by making use of very light construction and elimination of conventional retractable landing gear.
A very low stalling speed was also essential, since, while being retrieved, the aircraft had to maintain excellent controllability while matching the 70-80 kt maximum airspeed of the airship. Because of these limitations, only a few operational airship aircraft were direct modifications of existing carrier- or land based types. Rather, most were designed by the Navy’s BuAer and manufactured to these specifications by Grumman, Douglas, Brewster, Curtiss, or other contractors. Three general types of aircraft were developed for airship service: reconnaissance planes/fighters, “running boats”, and bombers. Key types are described below:
OZC Seafin This was a single seat high-wing reconnaissance type with fixed skyhook. It was heavily modified nu BuAer from an original Curtiss design for a fighter or advanced fighter trainer. Somewhat optimistically the OZC was also rated as a light fighter and provided with one synchronized .30 cal machine gun. The type had a combat radius 200 miles on internal fuel, 300 with auxiliary fuel tank. It served as a standard observation or reconnaissance plane on all airships 1939-1945, although by 1942 it only served on the ZRS-class ships. Like most airship types it had no conventional landing gear.
F3A Shrike This was a single seat, single engine low-wing monoplane based broadly on the Vought-143 fighter and adapted for airship use by Brewster. It was armed with two .synchronized .03 cal. machine guns and could manage a 150 mile radius on internal fuel. A fixed skyhook was mounted above the cockpit. Although the plane was provided with a retractable landing gear, these and the mechanism necessary to operate them were usually removed by airship crews to save weight. Simple stick landing gear could be fitted for conventional landings and takeoffs when necessary. Relatively few built were and they were rarely carried by airships operating in the Atlantic.
SBZD Attacker This was a one or two seat attack plane. It was designed by BuAer as a slightly smaller and much more lightly constructed version of the Douglas SBD Dauntless. The SBZD was not fitted with conventional landing gear and had a fixed skyhook. As originally designed, it was a single place attacker capable of carrying two depth bombs or three 250 lb bombs and armed with two fixed forward-firing .30 cal machine guns. Many Attackers were subsequently modified in service to carry an observer/gunner in a rear extension of the cockpit with a single defensive .30 cal machine gun. The SBZD was the navy’s standard airship-borne reconnaissance bomber 1941-1943. Most were built by Douglas.
PBZF Harrier The Harrier was without question the most versatile and capable ZRCV-based aircraft to se operational service. It was a small, twin engine ASW floatplane similar in concept to the Grumman Goose. Alone among airship-based aircraft the Harrier was designed for two occupants. It was capable of carrying up to 4 depth bombs, surface search radar, active/passive sonar buoys, and late in the war, two homing torpedoes. The plave had a 200 mile combat radius and was equipped with a semi-retractable skyhook in a pod on upper wing surface. With a wingspan of 49 feet, the PBZF was the largest aircraft routinely carried by the ZRCV ships, and its floatplane configuration promoted its aggressive use at sea, even though it lacked any defensive armament.
NZV Mule This was a twin engine “running boat” capable of carrying up to 6 passengers, supplies, and fuel for in flight servicing of the airship or its aviation unit. It was somewhat similar in appearance to the Lockheed Ventura but considerably smaller Due to their size and weight, Mules were never embarked on airships – rather they were used for supply and transferring personnel from ground bases or conventional aircraft carriers.
Other Types From time to time other aircraft were provided with temporary skyhooks and operated experimentally from the navy’s airships. Among these were Sea Hurricanes, F4F Wildcats, Fairey Swordfish, and Westland Lysanders.
Complement Mix Depending on the area of operations and the airship’s planned mission, the operational complement of aircraft embarked would vary. Early in the war, ZRCVs usually carried 4 Shrikes and 6 Attackers, or 5 Shrikes and 3 Harriers on convoy escort or patrol missions. Later, as the airships were used more as independent ASW platforms, the ZRCV aircraft compliment was often reduced to as few as 3 Harriers. This allowed the ships to carry a much heavier offensive payload of ordinance for themselves and their its aircraft. When operating independently against U-boats in the western Atlantic, individual ZRCVs often operated in tandem with a ZRS, the ZRS using its Seafin scouts to increase the team’s chance of locating surface submarines and the ZRCV using its Harriers to attack it.
US Naval Airship Nomenclature
As opposed to the British and Germans, who in World War 1 only assigned their rigic airships numbers, the US Navy assigned them both numbers and names in the same manner as surface combatants.
All airship numbers began with a letter prefix beginning with “Z” (which indicated “airship”, not “zeppelin” as commonly supposed), followed by additional letters indicating the ships’ type and function, finally followed by the ship’s unique fleet number indicating its sequence among commissioned naval airships of its type. Thus, “ZN” indicated “airship, non-rigid”, “ZR” indicated “airship, rigid”, “ZRS” indicated “airship, rigid, scout”, “ZRCV” meant “airship, rigid, aircraft carrier”, and so forth.
Other than the ZR-1, which was given the name USS Shenandoah, “Daughter of the Stars”, and the ZR-2, which was lost before being formally commissioned into the navy, the early rigid airships all were named after US cities: (USS Los Angeles, USS Akron, USS Macon, etc). This reflected less any set system at the time as it did a desire to cater to powerful and influential political supporters of the airship program. However, it did appear to have a certain logic, because most naval officers considered the large airships the airborne equivalents of scout cruisers, which were also named after cities.
With the eventual acceptance of rigid airships as regular fleet units – and especially the introduction of the ZRCV classes which were seen as more equivalent to light aircraft carriers than cruisers, the Navy felt the need to decide on a systematic nomenclature for the navy’s growing fleet of rigid airships. Initially BuAer proposed an entirely new system involving birds of prey or nautical weather events, both of which would have promised exciting and evocative nomenclature. However, since it already had five ships named for cities, the Navy decided to retain the use of city names for the new ZRCVs and ZRNs but also add famous historic American naval vessels or battles (which were also used for aircraft carriers) as potential name sources for the ZRCV airships.
US Airship Colors and Markings, 1922-1971
Military Airships
Color Schemes. In the interwar years, the fabric exterior of all US airships was covered with several layers of clear dope, followed by a silvery aluminum exterior coat. It was popularly believed that this was mainly for aesthetic purposes. Actually, reflective silvery dope was used to minimize solar heating of the lifting gas, which was important in maintaining predictable lift and trim. Beginning in 1940, as US entry into the war became increasingly likely, the Navy experimented with several alternative doping/painting camouflage schemes for large airships, the most radical being a disruptive pattern of white, black, silver, and light blue applied to USS Wichita.
Eventually in early 1942, the Navy settled on a standard two tone silver and grey “camouflage”. This scheme retained the reflective silver doping on the upper third of the airship, with the lower 2/3rds a very light non-reflective grey, essentially similar to US Navy measure 5-L Light Grey. It is questionable how effective any camouflage scheme was; no matter what color, a 900-foot long rigid airship operating between 2000 and 4000 feet above the sea is a hard thing to hide. After the conclusion of the war, all surviving ships reverted to overall silvery dope.
Markings and insignia. Prior to 1939 airships carried large national aircraft insignia on the lower hull immediately in front of the control car, and one on each side of the hull in front of the horizontal fins. The ship’s name (e.g. “Akron”) was painted in small letters directly in front of and just below the horizontal fins, on both sides. The airships sported a very large “U.S. Navy” (or in some case just “Navy”) on both sides of the ship near the midsection. They did not display any other identifying numbers. Rudder and elevator surfaces were painted in a vertical blue-white-red scheme. For a very brief period training airships (Los Angeles and the two ZRNs) had their horizontal and vertical fins painted high visibility yellow
With the outbreak of the European War in 1939, additional “neutrality” markings were added to US naval airships. These included large US flags painted on both sides of the hull above the control car, and a fourth national insignia on top of the ship. These were added to help ensure that US airships engaged in intelligence-gathering and training flights in the eastern Atlantic were not confused with surviving German passenger zeppelins and attacked by British or French aircraft. This precaution was almost certainly an over-reaction, given the fact that, after September 1, 1939, German commercial airships were operated only on a limited basis in Central Europe, and were grounded altogether after June, 1940.
In this context, however, it is interesting to note that for a brief time in late 1940, the Abwehr considered a scheme to refit and repaint Hindenburg as a virtual copy of the US Navy's USS Belleau Wood/Graf Zeppelin, provide her with a number of English-speaking Luftwaffe officers, and use her for intelligence gathering and reconnaissance for surface and subsurface commerce raiders in the Atlantic. The presumption was that the Allies would be reluctant to attack what appeared to be an American naval airship, making the Hindenburg almost immune while it carried out its missions. Thus, had this scheme found favor, there would have been a very real risk that US naval airships could have been operating in the general vicinity of German airships
After 1941, when it became obvious that US airships could never be confused with vessels of any other power, airplane-style national markings were reduced or eliminated. The vertical tricolor stripes on the rudders and elevators were eliminated and both lateral national insignia and the large “U.S. Navy” were removed. A single, small, national insignia was retained in front of the control car, more for morale reasons than any other, since it was barely larger than the roundels applied to regular aircraft and would be essentially useless for national identification at the ranges airships were readily visible to friend or foe. The style of this roundel underwent the same revisions as other US aircraft insignia, until the final blue and white “star and bar” was adopted. The small airship’s name on both sides of the aft hull was retained.
As “ships” that also flew, the Navy’s rigid airships had always occupied a halfway house between being considered aircraft and surface ships. In nomenclature they were treated as commissioned ships but were also given airplane-style roundels. Finally, in late 1944, the Department of the Navy determined, once and for all, that rigid airships were to be treated as fleet units, not aircraft. As a result, the small aircraft roundel in front of the control car was permanently eliminated, and in place of this each ship could paint a small official ship’s shield.
Throughout the war, a number of officially sanctioned and unsanctioned markings were also employed to enhance crew morale. This included officially sanctioned “victory” symbols painted on the control car, usually stars or submarine silhouettes, to denote successful missions, and campaign/battle ribbons that were awarded to the whole ships’ company, also displayed on the control car. Unofficial personal markings (slogans, pictures, etc) were also frequently painted on engine cars and gun stations by individual crewmember or watches.
After the war, the large “U.S. Navy” reappeared on both sites of the hull, and the ship’s name near the fins was enlarged slightly. Other than small battle and campaign ribbons, shown on the control car, all other wartime markings were eliminated.
Incidentally, all US Navy rigid airships were provided with naval ensigns and jacks, as well as a standard set of signal flags that could be raised (lowered actually) from the control car on weighted landing lines if radio or semaphore communication was impossible. Flags were rarely flown unless the ship was operating at less than 45kts. Only the national ensign was routinely flown, this from a special collapsible staff just aft of the lower fin.
The HTA Unit. The system of markings and national insignia on airships’ planes generally mirrored those used by other shipboard naval aircraft. One major difference was the general absence of standard Navy camouflage schemes. To minimize unnecessary weight, airship-borne planes were usually left with unpainted natural metal or doped fabric surfaces. On the other hand, because airship aviators considered themselves the elite pilots of the Navy, their planes sported a much wider array of brightly colored personal art than typical for the Navy, often featuring variations of the “trapeze artist” squadron markings first employed by the HTA unit assigned in 1934 to USS Macon. Because of their unpainted metal and colorful nose art, HTA units often looked more like they should be in the Army Air Corps, not the USN. Because of this, and as a result of natural rivalry with the airship aviators, other naval aviators often referred to their HTA unit colleagues as “The Army Clown Corps”
Civil Airships
Airships operated by Goodyear-Zeppelin’s AZTC and PZTC airlines sported a relatively simple livery, consisting of an overall aluminum doped hull with a 10 foot wide painted stripe extending the full length of the ship on each side of the hull. AZTC ships sported a blue stripe, while that used by the PZTC was red. US flags were painted on the upper and lower fins. Each ship’s name was painted in a cursive script immediately below the stripe, above the control car on the ship’s starboard side, while the full airline name was rendered in script on the port side. During the Second World War, when all civilian ships were taken over by the Navy for high speed bulk transport, all markings except the US Flags on the fins were removed. Since they were operated as civilian adjuncts, not regular naval units, they did not receive any naval markings, and retained their overall civil aluminum doping.
Appendix A. Reproduction of December 1942 Signal article allegedly authored by KM Kapitanleutnent Klaus Handel of the U-367.
We Destroy an Enemy Zeppelin
In this day of modern warfare the submariner sees many new and wonderful things. They see our U-boats deliver sudden destruction to the enemy while safely hidden under the sea. They see our powerful battleships and cruisers attack his convoys. They see Stukas deliver deadly bombs on the decks of his warships. They see long-ranged flying boats and Condor bombers magically find and destroy fat troopships, and they read about the naval forces of our Japanese allies delivering complete destruction to the American and British navies in the Pacific.
Thus, it is not surprising that we see the United States and Britain using increasingly desperate measures to combat our submariners in the Battle of the Atlantic. Informed Signal readers will remember that in 1939 the German Reich sold the zeppelin passenger airship LZ-130 to the United States as a goodwill gesture to the American people. Now, it seems that the US Navy has become so desperate in its attempt to defeat our U-boats that it has resorted to flying the LZ130 and fragile craft like it far out to sea to as escorts for troopships and transports headed to England. The report below by Kapitanleutnent Klaus Handel of the U-boat U-367 is a first-hand account of what actually happens when such relics from the First World War meet up with a modern ship of the German U-boat service and its well-trained crew.
“We had just completed a very successful mission off the eastern coast of the US and were heading home on the surface to celebrate when we first saw the enemy zeppelin floating at low altitude about 15,000 meters off our port bow. It appears the American commander saw us at about the same time because the airship turned and began heading straight for us. Although the zeppelin was almost 15 kilometers distant and hard to see in the low sun, I was able to discern through my binoculars that it launched two or three small airplanes (it may come as a surprise to most Signal readers, but the American navy is known to hook small attack planes on the LZ-130 and other zeppelins). As the planes neared us, I ordered an emergency dive to 60 meters. The American pilots released their bombs well behind us - we could hear the explosions as muffled crumps on the hydrophones. Several minutes later, we heard a second series of explosions, this time considerably closer to us.
“For over 36 hours, we played “cat-and mouse” with the enemy airship and its airplanes, rising to periscope depth or briefly surfacing to get our bearings and then submerging to easily avoid the inevitable air attack which followed. Unfortunately, the enemy seemed quite determined to follow us all the way to France and our batteries (necessary for travel under the sea) were becoming drained. I was also concerned that the enemy would call a more capable opponent (such as a destroyer) to assist in our pursuit.
“Thus, I determined to battle the airship using one of the oldest weapons in the warrior’s bag of tricks – deception. After the sixth ineffective air attack by the zeppelin, I ordered all of our decoys released and surfaced the boat as if in emergency. Immediately upon reaching the surface, we engaged the diesels and ran extra oil through them, exhausting clouds of dense, black smoke through the conning tower and all other vents. We were very fortunate because favorable breezes blew the smoky haze over ship’s conning tower and deck, hiding my crew as they manned the guns and spotting stations. Through the smoke we could see the American airplanes hooking on to the zeppelin, which was still several kilometers distant. One can only imagine how helpless we appeared to the enemy! A stationary submarine wallowing amidst smears of oil and debris and issuing dense black smoke from all open ports! To assist in the ruse, I ordered several crewmen to inflate life rafts and take to the sea as if abandoning ship.
“After a few minutes, the American zeppelin turned and headed straight for us. Apparently its commander had taken the bait and decided we were so helpless that he could use his fragile gasbag itself to deliver what he must have believed would be the final blow. I ordered the gun crews to aim for the small control car near the giant airship’s bow and hold their fire until I gave the order to engage.
“Finally, when the nose of the zeppelin was so close we could make out the faces on the enemy airmen in the control gondola, I gave the order. Our well-trained gunners scored immediate hits on the gondola, tearing it to pieces and ripping huge gashes in the fabric hull above it. Apparently this blow killed or crippled the American commander and other officers, because the zeppelin floated right over us without dropping any bombs. Our machine gunners then peppered its soft bottom as it flew overhead, and I could see small fires starting through rips in the hull fabric. Initially, we all thought the huge ship would explode in a ball of fire like the zeppelins of yore, but then I remembered that the Americans used non-flammable helium in their airships.
“After passing over us, the enemy began a slow turn to starboard and I ordered the gun crews to fire on the two large engine cars extending from the side of the ship. Again the range was very close, and we scored immediate hits. Our main 88mm deck cannon destroyed the starboard aft engine car with a single well-placed high explosive round, while the other engine was disabled by repeated light cannon and machine gun hits. Knowing the enemy was fatally crippled, I ordered the U-boat to flank speed to complete our escape. With its only power now coming from the undamaged portside engines, the enemy zeppelin entered into a sharper starboard turn on course to bring it just behind us. This gave my men one further opportunity to fire at the other side of the ship as it flew by. They made good use of the target practice, destroying or disabling both portside engines and putting many huge holes in the fragile hull. Countless pieces of debris fell into the sea, barely 100 meters below the 300 meter-long leviathan. The enemy was now drifting powerless and headed nose-down toward the Atlantic Ocean. As we cruised away from the battle site, we could see even more large pieces falling from many places on the doomed enemy craft. Knowing that it might still take several hours for the slowly descending hulk to actually strike the sea, and aware that enemy destroyers were probably heading our way, I decided it would be wiser to complete our escape as quickly as possible rather than stay on station and attempt to render assistance to the enemy crew as they abandoned their dying zeppelin for the waves. We resumed an easterly course and lost sight of the enemy as the sun began to set.”
Signal is proud to report that, before returning to sea, Kapitanleutnent Handel and his brave crew were invited to dinner with Grandadmiral Doenitz himself at the Grand Hotel Nauticus in Berlin where they all received special awards for their skill and bravery in this unusual and successful combat with a flying monster ten times their size.
Editor’s note: In many respects this article is a fairly accurate portrayal of the engagement between USS Sacramento and U-367. However, as might be expected, Handel (or the Signal writer ghost-writing his report) misinterprets or exaggerates the damage to the airship. While it is true that the second salvo from U-367 virtually destroyed the control car and killed all officers present, damage to the surrounding hull was substantially less than Handel believed was the case. Handel was also incorrect in mentioning “fires” within the hull. There were no such fires. It is possible the German commander was seeing muzzle flashes from .50 calibre machine guns being fired ineffectually at the U-boat from positions on the lower keel gangways. Handel is also incorrect in reporting damage to Sacramento’s portside engines. In fact, neither portside engine was damaged in the engagement. He saw them cease operation because they were deliberately stopped on orders from Lieutenant Micah Barnes, who had by this time assumed command of the airship from the emergency control station on the lower fin. Also, despite Handel’s belief the airship was going to crash, it was never in serious danger of being lost during the engagement. The many rips and holes he describes in the exterior envelope, although large, had little effect on the ship’s overall buoyancy since they were on the bottom quarter of the ship. The ship had assumed a strong nose-down attitude due to gas loss in the forward gas cells, but never came closer than 200 feet to hitting the surface. In fact, the pieces of “debris” the German captain describes falling from the ship were slip tanks for water and sand bag ballast being released on orders from Lt. Barnes to help her reach equilibrium. Sacramento did face serious danger of crashing several times during her heroic struggle to reach home, but this would not have been witnessed from the German submarine. Unfortunately, the Navy never had the chance to interview Kapitanleutnent Handel and his crew after the war because U-367 was sunk with all hands by the Canadian destroyer HMCS Ojibwa on June 12, 1943.