Why didn't Italian submarines surround Malta?

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Wargames
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Why didn't Italian submarines surround Malta?

Post by Wargames » 17 Feb 2020 06:05

When a British convoy was spotted leaving Alexandria, Egypt, the Italians had to know it was bound for Malta. Why didn't their submarines sit off the harbor and wait?

And why didn't the Italians mine the harbor entrance?

LColombo
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Re: Why didn't Italian submarines surround Malta?

Post by LColombo » 17 Feb 2020 11:34

There were Italian submarines deployed off Malta, most of the time. They could not get just outside the harbour because the British themselves had laid defensive minefields and had vessels and aircraft patrolling the coasts of Malta.

Italian warships laid several minefields near Malta, some of which claimed victims (HMS Gallant, Jersey...). They did not mine the harbour entrance for the same reason the British did not mine, say, the harbour entrance of Naples or Tripoli - there were defensive minefields.

Wargames
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Re: Why didn't Italian submarines surround Malta?

Post by Wargames » 18 Feb 2020 09:53

Thank you for the reply. Please excuse my answer as I'm not entirely satisfied, though you may be right.

You have described an anti-submarine minefield which is a very interesting concept. I was not aware of this. Yet I'm not aware of an Italian submarine being sunk off Malta's harbor by a mine either.

One would expect there to be a limit to such minefields such that, say, 60 miles off Malta an Italian submarine could sit and wait. Yet I see no record of an Italian submarine scoring such a hit. It's as if there were no Italian submarines off Malta at all. It seems that all British convoys from Alexandria arrived torpedo free at Malta.

Obviously, there was a reason. Somehow Malta was "submarine proof".

I'm not aware, for example, of Malta having anti-submarine ships or anti-submarine aircraft at Malta (At least in 1940.). For having a huge force of submarines, it would seem they could intercept a British convoy with more submarines than the British had transports.

To be honest I'm surprised this question hasn't been asked before.

Sid Guttridge
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Re: Why didn't Italian submarines surround Malta?

Post by Sid Guttridge » 18 Feb 2020 15:31

Hi Wargames,

The Italians had a large submarine fleet, but many of its boats were not state-of-the-art by German standards.

Convoys were, by definition, escorted - the Malta convoys particularly heavily so.

Malta also had its own effective air cover most of the time.

Furthermore, convoys were occasional. Without any advanced warning, the great majority of deployments in the hope of a random target would have been without result.

Anti-submarine minefields had been common since WWI. In the Mediterranean the Otranto barrage was the main one over 1915-1918.

If memory serves, Malta was often supplied with absolute necessities by the fast minelayers Abdiel and Manxman, which were difficult targets because of their speed.

Although larger surface units were withdrawn from Malta, it still operated coastal forces and its own submarines, which were threats to Italian submarines.

Finally, the Italian submarine arm also had other responsibilities both within and beyond the Mediterranean. British naval bases at Alexandria and Gibraltar had to be covered. Some boats were based in Ethiopia, some in the Black Sea and others operated with considerable success in the Atlantic from French U-boat bases.

Cheers,

Sid.

LColombo
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Re: Why didn't Italian submarines surround Malta?

Post by LColombo » 18 Feb 2020 16:23

Wargames wrote:
18 Feb 2020 09:53
One would expect there to be a limit to such minefields such that, say, 60 miles off Malta an Italian submarine could sit and wait. Yet I see no record of an Italian submarine scoring such a hit. It's as if there were no Italian submarines off Malta at all. It seems that all British convoys from Alexandria arrived torpedo free at Malta.
There were Italian submarines 60 miles from Malta, even closer than that. Picking random examples, Pier Capponi on 1-4 September 1940, thirty miles from Malta; Capponi again on 9 November 1940, 40-50 miles south-east of Malta, Uarsciek and Topazio in early December 1942 45-50 miles south of Malta, and so on. But being off Malta did not mean that the submarines would sight the convoy; sighting the convoy did not mean that the submarine could be able to close enough to attack; and closing enough to attack did not mean that the torpedoes would hit. Capponi, again, for instance made several attacks on Malta-bound convoys in 1940-1941, but never hit. Tembien was sunk (by ramming!) by the cruiser HMS Hermione in 36°21' N, 12°40' E durign Operation "Style". Convoys to Malta were rare and very heavily escorted, there were one or more destroyers for each merchant ship, plus often support forces with battleships, cruisers and aicraft carriers, carrying out a successful attack was extremely difficult.

I also think that relatively few convoys were sent from Alexandria to Malta. Most of them were sent from Gibraltar, and in these cases the Italian submarine command, if informed in time, seems to have preferred to lay barrages of submarines along the convoy's route both in the central and western Mediterranean, and/or to concentrate submarines in the chokepoint that is the Sicilian Channel. This worked greatly during Operation Pedestal (August 1942), less so in other instances.
Wargames wrote:
18 Feb 2020 09:53
For having a huge force of submarines, it would seem they could intercept a British convoy with more submarines than the British had transports.
As Sid says, part of the Italian submarine fleet had to cover the rest of the Mediterranean; on top of that, you have to detract from the numbers the thirty submarines transferred to the Atlantic in the summer of 1940, the elderly classes (Balilla, Pisani, Bandiera...) whose boats had a limited combat value, and consider that at any given time a certain percentage of the submarines would be undergoing maintenance, repairs, etc.

Wargames
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Re: Why didn't Italian submarines surround Malta?

Post by Wargames » 20 Feb 2020 01:55

LColombo: You seem well informed. Thank you for replying. Yours comes closest to my thinking. I'm uncertain about Italian maintenance but Germany could only maintain one third of its U-boats on station at any one time. Of the remainder, one third was undergoing maintenance and the other third was either on its way to, or on its way back, from its assigned patrol station. I would imagine that Italy, at best, could only maintain 50% of its boats on station in the Mediterranean. I show 30 boats on patrol in the eastern and western ends of the Sea. At 50% capacity, this would require 60 boats. Add 10 boats for those lost in first few days of the war and that's 70 boats. That becomes 78 when we add in Massawa and 106 boats when we add in the ocean subs. Throw in the "X" and "H" classes as obsolete and now we're over 110 boats. So I concluded the reason for no Italian submarines being at Malta was that there were none left to send.

However, on August 31, 1940 the Italian fleet put to sea to intercept Admiral Cunningham for the HATS convoy. This was a major planned intercept operation which included submarines (But I do not know their number only that they scored zero hits if they even fired at all.). It reasoned to me with Cunningham's destination known and with the short distance from Italy, they could get their submarines there first and just sit off the harbor and wait. The three British transports were guarded by four destroyers so the argument of heavy escort does not appear to apply and I know of no anti-submarine aircraft on Malta at the time. The conditions seem perfect for when the convoy arrived September 2 (The weather was not the best.). Something is clearly wrong with that assumption or the number of submarines sent was small via the above problem of none left to send. Do you know how many were sent? And did Italian submarines have their number of torpedoes they could launch restricted then? As that would cut their hits in half.

Thanks in advance. I admire your knowledge.

LColombo
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Re: Why didn't Italian submarines surround Malta?

Post by LColombo » 20 Feb 2020 10:41

Wargames wrote:
20 Feb 2020 01:55
However, on August 31, 1940 the Italian fleet put to sea to intercept Admiral Cunningham for the HATS convoy. This was a major planned intercept operation which included submarines (But I do not know their number only that they scored zero hits if they even fired at all.). It reasoned to me with Cunningham's destination known and with the short distance from Italy, they could get their submarines there first and just sit off the harbor and wait. The three British transports were guarded by four destroyers so the argument of heavy escort does not appear to apply and I know of no anti-submarine aircraft on Malta at the time. The conditions seem perfect for when the convoy arrived September 2 (The weather was not the best.). Something is clearly wrong with that assumption or the number of submarines sent was small via the above problem of none left to send. Do you know how many were sent?
According to "I sommergibili italiani 1940-1943" by Erminio Bagnasco and Maurizio Brescia, on 1 September 1940 Maricosom formed a submarine barrage south of Sardinia against "Hats", with Medusa, Diaspro, Alagi and Axum. They were deployed between Cape Spartivento (Sardinia) and La Galite island (Tunisia) but did not sight anything. The only submarine deployed off Malta in this period was Pier Capponi (30 miles south-east of Malta), joined in the following days (too late, I presume) by Durbo and Berillo. At 22:45 on 1 September Capponi sighted a destroyed and attacked it without success, being detected and heavily depth charged. On 3 September the old Des Geneys, on patrol southeast of Crete, sighted a group of British warships (probably at sea for "Hats") and tried to attack, but a change of course by the ships forced it to abort; the ships then passed over the submarine.
Wargames wrote:
20 Feb 2020 01:55
And did Italian submarines have their number of torpedoes they could launch restricted then? As that would cut their hits in half.
As far as I know, Italian doctrine about the launch of torpedoes (both by submarines and torpedo boats) favored "precision" launches of 1-2 torpedoes, in order not to waste torpedoes. Thus while British submarines usually fired full salvoes of 4-6 torpedoes, with greater expenditure but also greater chances to hit, Italian submarines seldom fired more than two torpedoes at a time, therefore the likelihood of hitting was also lower.

Sid Guttridge
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Re: Why didn't Italian submarines surround Malta?

Post by Sid Guttridge » 20 Feb 2020 13:50

Hi wargames,

Italian submarines couldn't just, ".....just sit off the harbour and wait" in any numbers for the reasons already given.

Besides, such a concentration would provide a target-rich environment for Malta's air and naval defences, which were usually very active.

It wasn't only the Italians who would assume their opponents' convoys would concentrate at Malta. The British might reasonably assume that Italian forces would do the same to intercept them.

Cheers,

Sid.

Wargames
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Re: Why didn't Italian submarines surround Malta?

Post by Wargames » 21 Feb 2020 08:05

I'm going with LColombo on this one. The Italian HATS response was a major operation and included submarines. Five submarines, of which only one was sent against the convoys three transports, is an inadequate number and even the later addition of two more (too late for September 2) is insufficient. Something is wrong with the Italian submarine force and it has nothing to do with Malta's air and naval defenses. It is in the number of submarines sent. Presumably this was all submarines that were available. If so, it demands an explanation. Either there is a very large number of submarines elsewhere on patrol in the Mediterranean (my explanation) or the number of submarines undergoing refit and maintenance exceeds the number on patrol which is contradicted by Italian naval design which planned for one half of all boats to be at sea at any one time during war.

I am curious if LColombo has any information that adds to our knowledge here. If I was correct that Italy maintained 30 boats at sea then - yes - Italy would be lucky to get even 5 submarines available for HATS. They're already elsewhere. Problem solved. But, if the figure is less than 30 boats, then there is a problem in that more should be available in Italy. The answer could be very informative and may involve refit times. For example, the submarine Adua performed 46 training missions between October 22, 1940 and March 12, 1941 before serving on a patrol that ended June 4, 1941 to return for a three month refit. That would be seven months and 12 days of operational use for three months off for refit or a ratio of more than two months at sea for every month in refit. The boat would be operational 70% of the time. Hence, my rough estimate that 50% could be at sea on patrol at any one time (allowing for time to get on station and return). Again, this math works if there are 30 boats at sea. Any other figure though could tilt the math and perhaps significantly. So I am curious what LColombo says.

Sid Guttridge
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Re: Why didn't Italian submarines surround Malta?

Post by Sid Guttridge » 21 Feb 2020 11:34

Hi wargames,

Italian submarines couldn't just loiter permanently off Malta in large numbers in the hope that some Allied merchantmen might turn up. If they were to be used efficiently, they had to respond to specific advance intelligence that a Malta convoy was in the offing. Interdiction of Malta wasn't their only responsibility, and was shared with their surface forces, their air force and the Germans. The whole apparatus ultimately failed, not just the submarine arm.

Cheers,

Sid

LColombo
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Re: Why didn't Italian submarines surround Malta?

Post by LColombo » 21 Feb 2020 20:59

Wargames wrote:
21 Feb 2020 08:05
I'm going with LColombo on this one. The Italian HATS response was a major operation and included submarines. Five submarines, of which only one was sent against the convoys three transports, is an inadequate number and even the later addition of two more (too late for September 2) is insufficient. Something is wrong with the Italian submarine force and it has nothing to do with Malta's air and naval defenses. It is in the number of submarines sent. Presumably this was all submarines that were available. If so, it demands an explanation. Either there is a very large number of submarines elsewhere on patrol in the Mediterranean (my explanation) or the number of submarines undergoing refit and maintenance exceeds the number on patrol which is contradicted by Italian naval design which planned for one half of all boats to be at sea at any one time during war.

I am curious if LColombo has any information that adds to our knowledge here. If I was correct that Italy maintained 30 boats at sea then - yes - Italy would be lucky to get even 5 submarines available for HATS. They're already elsewhere. Problem solved. But, if the figure is less than 30 boats, then there is a problem in that more should be available in Italy. The answer could be very informative and may involve refit times. For example, the submarine Adua performed 46 training missions between October 22, 1940 and March 12, 1941 before serving on a patrol that ended June 4, 1941 to return for a three month refit. That would be seven months and 12 days of operational use for three months off for refit or a ratio of more than two months at sea for every month in refit. The boat would be operational 70% of the time. Hence, my rough estimate that 50% could be at sea on patrol at any one time (allowing for time to get on station and return). Again, this math works if there are 30 boats at sea. Any other figure though could tilt the math and perhaps significantly. So I am curious what LColombo says.
Unfortunately I do not have a lot of data about refit times or the number of submarines that were available on average, only data for a few dates: on 10 June 1940, 92 boats were operational, 23 were "not ready"; on 1 January 1941, 67 operational, 30 "not ready"; on 1 Jan 1942, 65 operational, 26 "not ready"; on 1 Jan 1943, 37 operational, 40 not ready; on 8 Sept 1943, 45 operational, 32 not ready (note: this refers to all submarines - Mediterranean, Atlantic, Red Sea). They also mention that after June 1940 the number of submarines simultaneously deployed in the Mediterranean never exceeded 20-30.

Regarding the submarine situation at the time of "Hats", Bagnasco and Brescia mention that in the second half of August 1940 Naiade, Balilla, Des Geneys and Dessiè were deployed south of Crete, whereas Michele Bianchi was operating in the western Mediterranean; Dagabur, Ambra and Capitano Tarantini carried out defensive anti-submarine patrols in the Gulf of Taranto, but it is not clear when exactly in August these took place. In the first half of September, besides the boats which I already mentioned for the "Hats" operation, Nereide, Corallo, Sirena and Ruggiero Settimo operated south of Crete, while Uarsciek and Ondina operated off Egypt. Beilul, Squalo, Delfino and Narvalo operated in the Aegean, but again, when exactly during the month it not specified. Altogether in September 1940 thirty-two patrols were carried out by twenty-seven submarines. They mention that August and September 1940 saw a marked reduction in submarine activity compared to July (65 patrols by 59 boats) and June (105 patrols in just twenty days). I think that the transfer of the Betasom submarines in the Atlantic (27 boats) during the summer played a large part in that, along with the June losses (six submarines).

Sid Guttridge
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Re: Why didn't Italian submarines surround Malta?

Post by Sid Guttridge » 22 Feb 2020 12:05

Hi LColombo,

It looks as though the overwhelming majority of Italian submarine deployments you identify within the Mediterranean were to the east of Malta, whereas most convoys resupplying Malta came from the West.

Was this typical? If so, have you any idea why? Was the main aim to support the campaign against the British in the Middle East?

Cheers,

Sid.

Wargames
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Re: Why didn't Italian submarines surround Malta?

Post by Wargames » 22 Feb 2020 13:13

LColombo wrote:
21 Feb 2020 20:59
Unfortunately I do not have a lot of data about refit times or the number of submarines that were available on average, only data for a few dates: on 10 June 1940, 92 boats were operational, 23 were "not ready"; on 1 January 1941, 67 operational, 30 "not ready"; on 1 Jan 1942, 65 operational, 26 "not ready"; on 1 Jan 1943, 37 operational, 40 not ready; on 8 Sept 1943, 45 operational, 32 not ready (note: this refers to all submarines - Mediterranean, Atlantic, Red Sea).
This averages out to 64% operational. No doubt war shortages contributed to this as through January, 1942 they averaged 71% operational. Your information seems pretty consistent with 67% operational if not higher

They also mention that after June 1940 the number of submarines simultaneously deployed in the Mediterranean never exceeded 20-30.
Viewed in terms of total submarines, if the 115 boats of June 1940 allowed for 30 at sea, that would be 1 out of 3.8 submarines. And, if the 77 submarines of January, '43 and September 8, '43 allowed for 20 at sea, that would be 1 out of 3.85 submarines, a very consistent figure.

The conclusion I reach is that the number of submarines on patrol is roughly 1 out of every 3.83 available total and, prior to 1943, at least 67% operational. Thus, given the 97 submarines available on January 1, 1942 some 25 would be on patrol. Given 67% operational, this would be 25 out of 65 submarines total available.

The above figures include ocean submarines which can (and should) be subtracted out as well as two coastal submarines at Massawa. Thus, the 115 subs of June, 1940 becomes 85 Mediterranean boats of which 1 in 2.8 are at sea (30 boats) of at least "57" operational (67%). The actual number on that date would have probably been closer to 68 boats operational given the actual 80% operational figure at the time versus my estimated.

Basically 50% of all operational boats are on patrol and the other 50% are either on their way to patrol or on their way back or a slightly better ratio than German U-boats. For the August 31 HATS convoy we would obtain, after 10 boats sunk, 75 Mediterranean boats of which 27 are on patrol and another 27 in route or returning or 54 boats total. The number of operational boats available at 67% is 50 or 60 at 80% creating a maximum number of submarines that can be sent to Malta as being 6 or as few as minus 4 for 2 boats on average. You cited 1 actual (the other 4 boats were over 300 miles away.). 2 versus 1 is close enough. I can make this even more accurate by subtracting out the 7 obsolete submarines that are counted in the 115 total submarines and get exactly 1 Italian submarine at Malta.

The answer to my question of why Italy didn't surround Malta with submarines when a Malta convoy was spotted was because they were already on assigned patrol. Italy issued preplanned patrols to all its submarines and trying to give new orders to these boats was very difficult to do.
The number of boats Italy could even manage to find in port to send out could probably be counted on one hand. Historically speaking, it means the Italian submarine fleet was not offensive but defensive (being used almost exclusively for recon missions). This thinking obviously invites a "What if?" scenario.

My thanks to LColombo. The answer is as I suspected but it required confirmation.

Watch your mailbox, LColombo. When I find someone as well informed as you, I take advantage of it. :milwink:
Last edited by Wargames on 23 Feb 2020 07:20, edited 1 time in total.

Wargames
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Re: Why didn't Italian submarines surround Malta?

Post by Wargames » 23 Feb 2020 07:07

Sid Guttridge wrote:
22 Feb 2020 12:05
Hi LColombo,

It looks as though the overwhelming majority of Italian submarine deployments you identify within the Mediterranean were to the east of Malta, whereas most convoys resupplying Malta came from the West.

Was this typical? If so, have you any idea why? Was the main aim to support the campaign against the British in the Middle East?

Cheers,

Sid.
Admiral Somerville was at sea from Gibraltar during the HATS convoy. Somerville provided the Italians with false information he intended to attack Genoa but with the real attack on Cagliari on August 31. On 1 September, half way between the south-eastern tip of Sardinia and the western tip of Sicily, Somerville split his force in two. Force H turned to the north, in preparation for a second attack on Cagliari (made early on 2 September, this attack was foiled by haze and low cloud), while Force F continued on to the south east, heading for Malta and leading to four Italian submarines being 300+ miles to the east side of Malta versus Somerville. Those submarines were probably on patrol there to begin with.

It was normal to employ 10 Italian submarines in the western Mediterranean versus Gibraltar (up to 20 versus Alexandria). The 10 subs were pretty useless not only because Somerville seldom showed but, when he did, he'd usually cheat the international rules of war and sail through French waters at night (The Italians obeyed international law and stayed out of French waters until Pedestal.). By passing through French waters at night the French were left unaware their waters had even been violated.

LColombo
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Re: Why didn't Italian submarines surround Malta?

Post by LColombo » 23 Feb 2020 10:11

Sid Guttridge wrote:
22 Feb 2020 12:05
Hi LColombo,

It looks as though the overwhelming majority of Italian submarine deployments you identify within the Mediterranean were to the east of Malta, whereas most convoys resupplying Malta came from the West.

Was this typical? If so, have you any idea why? Was the main aim to support the campaign against the British in the Middle East?

Cheers,

Sid.
Hello Sid,
I don't know. Note however that this is just the situation for the "Hats" convoy. During operation "Harpoon" in June 1942, for instance, there were sixteen submarines deployed in the central and western Mediterranean; during operation "Pedestal" in August (the only time Italian submarines had considerable success against a Malta convoy) there were seventeen (five between the Balearic Islands and Algeria, ten near the western approaches of the Sicilian Channel, one north of Cape Bon, one east of Linosa and west of Malta).

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