"Corregidor of the Red Sea" or 'Can Italy shut down supplies to Egypt?'

[Magnum]

During Italian rule, Leros, with its excellent deep-water port of Lakki (Portolago), was transformed into a heavily fortified aeronautical and naval base, "the Corregidor of the Mediterranean", as Mussolini boasted.

https://en.wikipedia.org/wiki/Battle_of_Leros#Background

POD: Mussolini decides to spend the money on a new fortress in Eritrea instead, so that he may be able to shut down naval traffic through the Bab-El-Mandeb Strait

The central piece of the puzzle would be the "Cannone da 381/50 Ansaldo M1934":

(OTL, it was used mainly on the Littorios)

With an effective range of 42km, they are more than capable of reaching targets on the other side:

They would be housed in large turrets build to withstand most hits.

The guns themselves would be supported in their efforts by a mix of minefields, torpedo boats, midget submarines and aircraft.

Since the Straits of Messina would also be extremely hazardous to convoys as well, the only other options for supplying a force in Egypt from Britain would be overland from Kenya or Iraq.

Bypassing Italian East Africa by land would be very difficult, as railroads from Kenya only reached southern Uganda at this point, leaving a large gap between them and the sinlge-track crappy railroad that was in Sudan, which itself ran only up to Wadi Halfa (from there, supplies would have to be loaded up on the Nile and transported downriver until they reached the Egyptian rail network)

Iraq was equally problematic, as the railroad only ran to Baghdad, meaning there would be a vast desert to cross until those supplies reached ports in French Syria.

So, in theory, blocking the Red Sea would make reinforcing Egypt incredibly difficult, and require the Anglo-French to consistently run convoys through the Messina Strait, where Italian torpedo boats, submarines and aircraft could act as force multipliers in any naval engagement (see e.g. Operation Pedestal).

Thus, much like the Maginot Line, a "Corregidor on the Red Sea" would be built not to directly confront enemies, but to force them to go a different, more favorable route (in the former case, through Belgium).

So, questions:

1. Any flaws in the above logic ?
2. Could this blockade actually block the Red Sea?
3. What are the likely British countermeasures?

 

[Carl Schwamberger]

Corrigidor is one comparison. What are the details of its destruction and capture?

 

[Magnum]

Corrigidor is one comparison. What are the details of its destruction and capture?

Incessant artillery attacks, followed by an infantry assault (which I guess you already knew).

The difference is that here, the British would not have artillery in range to hit this Italian fortress - they would need to either commit a ground force during a period when they could hardly afford it OR risk the battleships of the Mediterranean fleet

 

[Carl Schwamberger]

...
The difference is that here, the British would not have artillery in range to hit this Italian fortress - they would need to either commit a ground force during a period when they could hardly afford it ...

Sounds like the Japanese situation. The had a five month operation to clear the adjacent artillery position, then made the direct attack.

 

[Catsmate]

I like this. Very Guns of Navarone.

 

[Magnum]

Sounds like the Japanese situation. The had a five month operation to clear the adjacent artillery position, then made the direct attack.

The only thing Corregidor was blocking was the use of Manilla harbor.

"Italian Corregidor of the Red Sea" would be interdicting supplies to Egypt, something far more serious and urgent.

Let's say they do commit a ground force to British Somaliland prior to the May 1940, intending to use it to take the fortress, should the Italians enter the war. What we need to ask ourselves is: Does this new Army come at the expense of the force in Egypt or of that in Flanders?

 

[Michele]

2. If the key asset is the guns, the answer is no. The Germans had a dozen guns of varying calibers overlooking a strait of similar width, Dover. Most were of smaller caliber, but there were a couple of excellent 40.6cms, too. They only forced the British convoys to take precautionary measures (including navigation at night, in many cases), and they only sank a couple of ships in the whole war. The British had (roughly) equivalent assets on their side, and the Germans kept sending small coastal convoys along; I think no more than half a dozen ships were sunk in the whole war.

Add to all that the fact that the 381mms were especially unsuitable for this task.

Now, if the guns are only a secondary asset in a deployment of other forces, then maybe the British have some problems.

In any case, Assab fell in June 1941. If this coastal battery/strengthened naval base really is a thorn in the side, given how the campaign was going the British could probably simply hasten the operation by about three months, moving it up to March 1941. Throughout 1940, fast and well escorted convoys through the Med could be forced through with sustainable losses; it was only in January 1941 that things turned much for the worse there. So we're looking at a 3 months window, or 6 if you go with the historical date for the conquest of Assab.

 

[Carl Schwamberger]

...
In any case, Assab fell in June 1941. If this coastal battery/strengthened naval base really is a thorn in the side, given how the campaign was going the British could probably simply hasten the operation by about three months, moving it up to March 1941. Throughout 1940, fast and well escorted convoys through the Med could be forced through with sustainable losses; it was only in January 1941 that things turned much for the worse there. So we're looking at a 3 months window, or 6 if you go with the historical date for the conquest of Assab.

Pretty much my thoughts. I'd not time or priority to look up the dates. If this battery really is a threat the Brits will redirect the campaign and set forward effort aimed at it.

 

[naraic]

2. If the key asset is the guns, the answer is no. The Germans had a dozen guns of varying calibers overlooking a strait of similar width, Dover. Most were of smaller caliber, but there were a couple of excellent 40.6cms, too. They only forced the British convoys to take precautionary measures (including navigation at night, in many cases), and they only sank a couple of ships in the whole war. The British had (roughly) equivalent assets on their side, and the Germans kept sending small coastal convoys along; I think no more than half a dozen ships were sunk in the whole war.

Agreed, just because you can fire out to a certain range doesnt mean you can fire at that range and be accurate.

I'm going to put the odds at of hitting for any given shot outside of 20km at around 1 in 200. With a barrel of less than 400 rounds needing to change a barrel for every two hits sounds crazy.

 

[MerryPrankster]

Pretty much my thoughts. I'd not time or priority to look up the dates. If this battery really is a threat the Brits will redirect the campaign and set forward effort aimed at it.

What effects might that have on the campaign, operations elsewhere, etc.?

 

[Carl Schwamberger]

Don't know. Have not read anything on this portion of the war in four decades.

 

[I want to learn]

I feel like such fortifications could have been quite dangerous to the allies, but if Italian strategic leadership was the same as OTL, they would just be another boondoggle.

 

[BlondieBC]

Incessant artillery attacks, followed by an infantry assault (which I guess you already knew).

The difference is that here, the British would not have artillery in range to hit this Italian fortress - they would need to either commit a ground force during a period when they could hardly afford it OR risk the battleships of the Mediterranean fleet

You have to use ground forces. In most cases, naval fire on land based batteries only disables the batteries, it does not destroy them. The most common reason that batteries are disable is they are buried by the dirt throw up by the naval gun fire. The second most common reason is you hit the ammo supply. Both of these can be fixed given a few hours to days to weeks. The odds of a naval round directly hitting a land based artillery piece and physically breaking the gun is very, very low.

It is a pretty standard text book on how you take out these guns. You land superior land forces outside of the land based batteries, and then attack the land based batteries from the rear.

 

[BlondieBC]

The only thing Corregidor was blocking was the use of Manilla harbor.

"Italian Corregidor of the Red Sea" would be interdicting supplies to Egypt, something far more serious and urgent.

Let's say they do commit a ground force to British Somaliland prior to the May 1940, intending to use it to take the fortress, should the Italians enter the war. What we need to ask ourselves is: Does this new Army come at the expense of the force in Egypt or of that in Flanders?

Egypt. Or maybe other colonial possessions.

 

[Aber]

https://en.wikipedia.org/wiki/Battle_of_Leros#Background

POD: Mussolini decides to spend the money on a new fortress in Eritrea instead, so that he may be able to shut down naval traffic through the Bab-El-Mandeb Strait

1. Any flaws in the above logic ?
2. Could this blockade actually block the Red Sea?
3. What are the likely British countermeasures?

1 How does Italy keep this fortress supplied? - the land route goes through British controlled Sudan, and the sea route either via the Suez canal, or around Africa.
2 Not really. OTL the Italians had a naval flotilla based in Eritrea which did not achieve much:

On 10 June 1940, the day Italy declared war, the Italian Red Sea Flotilla had seven destroyers organized into two squadrons, a squadron of five Motor Torpedo Boats (Motoscafo Armato Silurante, or MAS) and eight submarines organized into two squadrons. The main base was at Massawa, with other bases at Assab (also in Eritrea) and Kismayu, in southern Italian Somaliland.[1]

https://en.wikipedia.org/wiki/Red_Sea_Flotilla
3 Aden is a major British naval centre which can be used as a base for escorts. Long term solution is land invasion - the British successfully invaded Abyssina from India as far back as 1868.

 

[BlondieBC]

Agreed, just because you can fire out to a certain range doesnt mean you can fire at that range and be accurate.

I'm going to put the odds at of hitting for any given shot outside of 20km at around 1 in 200. With a barrel of less than 400 rounds needing to change a barrel for every two hits sounds crazy.

It is higher. The rule of thumb is land base guns are 3 times more accurate than the same gun on a ship. You don't have to account for the land base gun moving like you do for a BB moving. So the best idea is to look at the hit ratios of surface battles of WW2 and divide the number by 3.

As to another person post about Dover, a gun is only a part of the defensive package. If the Italians only put few few guns in the fortress, it will be far, far less effective than building a defense that also has smaller caliber land based guns. Small surface craft. Recon airplanes. Fighters. Land based naval bombers.

 

[BlondieBC]

1 How does Italy keep this fortress supplied? - the land route goes through British controlled Sudan, and the sea route either via the Suez canal, or around Africa.
2 Not really. OTL the Italians had a naval flotilla based in Eritrea which did not achieve much:

https://en.wikipedia.org/wiki/Red_Sea_Flotilla
3 Aden is a major British naval centre which can be used as a base for escorts. Long term solution is land invasion - the British successfully invaded Abyssina from India as far back as 1868.

Supply is a major issue, but this is true at any isolated naval base from Singapore to Tsingtao to Manila. The cutoff bases have to have very substantial supplies of ammunition and other things that can't be secured from local sources. A realistic amount of time to setup a base like this is probably a half decade or more, well, if we use the normal rate peace time governments move. So we would need a 1934 or earlier decision to have the base running. This is the down side.

Now for the upside. The base is relatively cheap. You can build it with the guns of the ships you scrap in this 5 plus year build period. You may need to suppliment some with modern guns of DD or smaller size. Local labor is cheap. You may consider also using local soldiers, at least as the enlisted. Since it is in a low priority area, you use planes nearing the end of their useful life. And you accept that all isolated bases eventually fall. The big mistake Italy made in this area in WW2 was committing too many good units and good equipment to the sideshow front.

Now if the information of the size of the Italian fleet is accurate, they seriously under performed.

 

[galileo-034]

Minding that if Mussolini was to build that Corregidor of the Red Sea, and the geostrategic picture it would make, the British would unavoidably take it into account in their war planning and adjust it in consequence. Even though Italy remains neutral in the beginning, I have no doubt you have Churchill ready with a long planned operation out of the box on the minute Italy declares war, with ships and troops already allocated ready to go for it.

 

[Deleted member 1487]

What we need to ask ourselves is: Does this new Army come at the expense of the force in Egypt or of that in Flanders?

Egypt. Can't get supplies and men in nearly as easily to Egypt, so might as well use those forces to open up supply lines to them via sea. Having the Mediterranean fleet locked down in the East Mediterranean isn't strategically acceptable. That said the Italian forces invading Egypt in 1940 are no threat due to their supply issues, so leaving them alone to deal with the much more threatening East Africa situation is no big deal. That does potentially remove commitment of German forces to North Africa in the long run AND make British commitment to Greece impossible until both Italian threats in East Africa and Libya/Egypt are dealt with. So that could well push off any German commitment to the Mediterranean until after Barbarossa, which might make it extremely difficult to actually then put forces there.

This POD could be very strategically important.

What effects might that have on the campaign, operations elsewhere, etc.?

See above. At very least Operation Compass and Greek intervention is off the table (assuming Italy still invades Greece), which would well change the outcome of that campaign in Italy's favor despite Germany likely not getting involved (the 5th Cretan division freed up by British help was important to the war with Italy). German forces then not in the Mediterranean prior to Barbarossa go to Barbarossa and change a lot there.

 

[Albidoom]

Minding that if Mussolini was to build that Corregidor of the Red Sea, and the geostrategic picture it would make, the British would unavoidably take it into account in their war planning and adjust it in consequence. Even though Italy remains neutral in the beginning, I have no doubt you have Churchill ready with a long planned operation out of the box on the minute Italy declares war, with ships and troops already allocated ready to go for it.

Indeed. Depending on when the construction of that fortress would begin it could also have serious effects on the Second Italo-Ethiopian War. Probably not joining the war but at least the Embargo against Italy might be done more thoroughly and some supplies might get sent to Abyssinia.