Tom from Cornwall wrote:Carl,
Thanks for the reply. I see what you mean about the developing trend, but I also thought that Mar 43 was particularly horrendous. Will have to go back to some more detailed sources. I also get the point about the shipping used to support the forces in Torch and how they could have been used to support BOLERO. I've always thought that the argument that the capture of Sicily in July 1943 did save shipping as it meant that convoys could go through Med rather than round Africa did make sense and was the clincher in the whole argument. Will see if I can find out if there are any in-depth statistical studies that answer that question one way or another.
regards
Tom
Tom
Went back through Hughes & Costello. No easy answer. They expend nearly 100 pages on the worst period of the submarine battle from January 1942 through March 1943. Here are a few bits that add to the broad picture. number are total estimated for lost to German Italian subs globally. 'Atlantic' indicates losses in North & Mid Atlantic.
1st Qtr 1942
Cargo ship tons built........800,000
Cargo ship tons sunk......2,100,000
Ships sunk......................... 225 Atalntic
Subs operational....................45 Atlantic
Subs sunk............................11
2d Qtr
Cargo ship tons built........850,000
Cargo ship tons sunk......1,350,000
Ships sunk......................... 240 Atlantic
Subs operational....................60 Atlantic
Subs sunk............................10
These first two quarters were when the submarine fleet was concentrated against the US waters, first the Atlantic coast, then the Carribean. The helpfull map in H & Gs text shows about 80% of Allied ships sunk were in or near US waters, with a concetration of tankers sunk (20+) on the approaches to the South American oil ports. The bulk of the subs sunk were in the central or eastern Atlantic
3rd Qtr
Cargo ship tons built......3,000,000
Cargo ship tons sunk......2,750,000
Ships sunk......................... 290 Atlantic
Subs operational....................95 Atlantic
Subs sunk............................32
In this quarter Doneitz shifts the submarine patrols back to the Atlantic. The US has instituted effective convoy systems in the west Atlantic, and effective patrols by medium range (600 NM) aircraft. I'll have to check other sources, but IIRCC the Germans broke into the British convoy codes starting in this period. Demands from the Royal Navy for very long range ASW aircraft became adamant at this time. Harris supported by Chruchill responded that none could be spared, US Adm King provided none for the USN Atlantic ASW forces, tho over 70 were ordered to the Pacific & Carribean. This leaves a gap in air coverage mid Atlantic.
4th Qtr
Cargo ship tons built......2,500,000
Cargo ship tons sunk......2,000,000
Ships sunk......................... 260 Atlantic
Subs operational..................100 Atlantic
Subs sunk............................34
Demands for VLR aircraft to patrol the mid Atlantic are unfullfilled. Coastal command is able to fly one squadron of Liberators with the search radar. Effectively 10-12 aircraft daily that can overfly the mid Atlantic. The USN deploys nearly 100 to cover the Pacific against Japanese submarine raiders. Organization in October of the Torch convoys pulls escourt ships from the convoys to the UK and the other routes. The map shows the cargo ships sunk concentrated in the mid Atlantic, with a secondary concentration off the South America oil ports. Attacks decline in December & the Allied total losses fall to only 300,000 tons for the month.
1st Qtr 1943
Cargo ship tons built......2,750,000
Cargo ship tons sunk......1,500,000
Ships sunk......................... 200 Atlantic
Subs operational...................100 Atlantic
Subs sunk............................40
Very little January activity & low losses continue from December in the North Atlantic. RN reports in January the situation is critical & if losses in the North Atlantic continue at the previous rate the UK will have no reserves of critical items in two months. At the January Symbol confrence @ Casablanca Brooke & co argue the US Bolero plan cannot be executed in the spring of 1943 due to the lack of escourts for the number of convoys needed. Thus precluding sufficent strength for a 1943 sledgehammer. Apparently this does not preclude a build up for completion of the African campaign and the Husky operation scheduled for the summer. In Febuary the submarines surge again against the north Atlantic convoys with sucess. March convoy losses are serious with losses of up to 20%. Over a quarter of the ships lost to submarines were stragglers damaged by winter storms and unable to keep up with the convoys.
None of the books I have give any clear numbers for how much ship capacity was used to support the med Ops in 1943. Hughes & Costello does mention that six escourt groups were used to secure the convoys to the Med that winter & spring, but that is still a bit vague. Roosevelt directs Eisenhower to provode some VLR aircraft to ASW patrols over the Atlantic from the 12th Air Force 'if the can be spared from other operations'.
2d Qtr
Cargo ship tons built......3,000,000
Cargo ship tons sunk.........950,000
Ships sunk......................... 120 Atlantic
Subs operational....................90 Atlantic
Subs sunk............................73
Donitz withdraws from the mid Atlantic in April as additional VLR aircraft appear. Mechanical exhaustion interfers with keeping the large wolf packs active in the North Atlantic. In late spring several large wolf packs attempt to attack the Mid Atlantic convoys to the Med. They are continually suppressed by air cover from VLR and carrier based aircraft. Also, attacks on subs leaving the French ports become more effective & the transit time to patrol stations is increased. Losses in this transit become serious.