Question for you U-Boat experts

[syscom3]

Question for you WW2 U-Boat experts:

Do you know of a website that lists the numbers at sea during any given month?

Or even know offhand from your material?

 

[Gnomey]

This might help:

uboat.net - The U-boat War 1939-1945

 

[DerAdlerIstGelandet]

Yeap that is the best website on U-Boots. It even lists the fate of each U-Boot. Very good website.

 

[evangilder]

That seems to be the most comprehensive site for U-boat operations. I have used that for reference on several occasions.

 

[johnbr]

Yes this a great site for info on uboat.

 

[Civettone]

That's a great site indeed but I can't remember that they have those figures. Or at least I didn't see them the last time I was reading through it.

Kris

 

[AL Schlageter]

Got this off some BB somewhere, sometime.

1939:
Allied and Neutral ship tonnage sunk by German and Italian submarines (#ships, GRT)
Sep39 48/178,621
Oct39 33/156,156
Nov39 27/72,721
Dec39 39/101,823
Tot39 147 (36.75/month)/509,321 (127,330.25/month)

British merchant ship construction capacity from 1939-1941 did not exceed 1.2 million GRT per year.
US merchant ship construction in 1939 was 0.242 million GRT.

Number of U-Boat patrols (combat patrols only, does not include tanker/resupply missions)/losses/aborts prior to contact in principle theaters (North Atlantic, South Atlantic, Indian Ocean, and the Americas)
Aug39 19/2
Sep39 3/0
Oct39 13/3
Nov39 10/1/1
Dec39 5/1/1
Tot39 50/7/2 (an average of 10 patrols per month and 14% lost)

Thus for 1939, an average of 2.94 ships were sunk per patrol and one U-Boat was lost per 21 ships sunk (note that throughout these averages will be slightly inflated since they do not include the minor contribution of the Italian submarine fleet.)

1940:
Allied and Neutral ship tonnage sunk by German and Italian submarines (#ships, GRT)
Jan40 53/163,029
Feb40 50/182,369
Mar40 26/69,826
Apr40 6/30,927
May40 14/61,635
Jun40 66/375,069
Jul40 41/301,975
Aug40 56/288,180
Sep40 60/288,180
Oct40 66/363,267
Nov40 36/181,695
Dec40 46/256,310
Tot40 520 (43.33/month)/2,462,867 (205,238.91/month)
US merchant ship construction for 1940 was about 0.5 million GRT.

Number of U-Boat patrols (combat patrols only, does not include tanker/resupply missions)/losses/aborts prior to contact in principle theaters (North Atlantic, South Atlantic, Indian Ocean, and the Americas)
Jan40 8/2
Feb40 10/3
Mar40 10/2
Apr40 19/3
May40 8/0/2
Jun40 18/3/1
Jul40 4/0
Aug40 16/2/1
Sep40 12/0
Oct40 13/2
Nov40 14/1
Dec40 6/0
Tot40 138/18/3 (an average of 11.5 patrols per month and 13% lost)

Thus for 1940, an average of 3.77 ships were sunk per patrol and one U-Boat was lost per 28.89 ships sunk.

1941:
Allied and Neutral ship tonnage sunk by German and Italian submarines (#ships, GRT)
Jan41 23/129,711
Feb41 47/254,118
Mar41 41/236,549
Apr41 41/239,719
May41 63/362,268
Jun41 66/325,817
Jul41 26/112,624
Aug41 27/85,603
Sep41 57/212,237
Oct41 28/170,786
Nov41 15/76,056
Dec41 23/93,226
Tot41 457 (38.08/month)/2,298,714 (191,559.5/month)
US merchant ship construction 1941 0.804 million GRT

Number of U-Boat patrols (combat patrols only, does not include tanker/resupply missions)/losses/aborts prior to contact in principle theaters (North Atlantic, South Atlantic, Indian Ocean, and the Americas)
Jan41 10/0
Feb41 18/3/2
Mar41 15/3/3
Apr41 14/2/2
May41 21/0/2
Jun41 22/2/3
Jul41 24/1/9
Aug41 42/5/9
Sep41 38/0/2
Oct41 37/0/6
Nov 41 27/5/5
Dec41 49/4/6
Tot 41 287/25/49 (an average of 23.9 patrols sailing per month and 8.7% lost)

Thus for 1941, an average of 1.59 ships were sunk per patrol and one U-Boat was lost per 18.28 ships sunk.

1942:
Allied and Neutral ship tonnage sunk by German and Italian submarines (#ships, GRT)
Jan42 56/310,224
Feb42 72/429,255
Mar42 93/507,514
Apr42 81/418,161
May42 129/616,835
Jun42 136/636,926
Jul42 96/467,051
Aug42 117/587,245
Sep42 96/461,794
Oct42 89/583,690
Nov42 126/802,160
Dec42 64/337,618
Tot42 1,155 (96.25/month)/6,158,473 (513,206.08/month)
British and Canadian merchant ship construction 1942 1.8 million GRT
US merchant ship construction 1942 5.433 million GRT

Number of U-Boat patrols (combat patrols only, does not include tanker/resupply missions)/losses/aborts prior to contact in principle theaters (North Atlantic, South Atlantic, Indian Ocean, and the Americas)
Jan42 50/2/5
Feb42 29/3/2
Mar42 32/2
Apr42 37/2/2
May42 23/3
Jun42 39/9/5
Jul42 45/7/3
Aug42 58/10/4
Sep42 52/8/8
Oct42 62/6/10
Nov42 54/8/6
Dec42 59/8/7
Tot42 540/68/57 (an average of 45 patrols sailing per month and 12.6% lost)

Thus for 1942, an average of 2.14 ships were sunk per patrol and one U-Boat was lost per 16.99 ships sunk.

1943:
Allied and Neutral ship tonnage sunk by German and Italian submarines (#ships, GRT)
Jan43 44/307,196
Feb43 67/362,081
Mar43 110/633,731
Apr43 50/287,137
May43 46/237,182
Jun43 17/76,090
Jul43 46/237,777
Aug43 20/92,443
Sep43 16/98,852
Oct43 20/91,295
Nov43 9/30,726
Dec43 8/55,794
Tot43 452 (37.67/month)/2,510,304 (209,192/month)
US merchant ship construction 1943 13.081 million GRT

Number of U-Boat patrols (combat patrols only, does not include tanker/resupply missions)/losses/aborts prior to contact in principle theaters (North Atlantic, South Atlantic, Indian Ocean, and the Americas)
Jan43 61/13/11
Feb43 72/8/9
Mar43 59/16/10
Apr43 95/35/18
May43 55/23/9
Jun43 46/23/9
Jul43 39/27/7 (49 total patrols of all types)
Aug43 33/12/6
Sep43 32/11/10
Oct43 62/23/9
Nov43 36/9/4
Dec43 31/10/2
Tot43 621/210/104 (an average of 51.75 patrols sailing per month and 33.8% lost)

Thus for 1943, an average of 0.73 ships were sunk per patrol and one U-Boat was lost per 2.15 ships sunk.

So, overall, the most successful year for the U-Boats was 1940, before the expansion of the force allowed for an increase of more than about a dozen patrols sailing per month, and well prior to the entry of the US and its shipbuilding capacity into the war. Worse, the performance of the U-Boat force in 1941 and 1942 never exceeded its performance in the first months of the war. And, after 1943 the U-Boat campaign became ever less relevent to the outcome of the war.

Allied and Neutral ship tonnage sunk by German and Italian submarines (#ships, GRT)
Tot44 125/663,308
Tot45 63/284,476

US merchant ship construction for 1944 was 12.257 million GRT
US merchant ship construction for 1945 (through 1 May) was 3.548 million GRT

U-Boat Fleet to 1Sep42
On 19Aug39 there were 57 U-Boats in commission, 20 sea-going U-Boats and 18 'ducks' were fully ready to put to sea
Total number U-Boats deployed to 1Sep42 275
Total number lost 94
Total number retired 10
Total number available 171

U-Boat Fleet 1Sep42 to 1May45
Total number deployed 1Sep42 to 1May45 531
Total number lost 1Sep42 to 1May45 568

British controlled merchant shipping over 1,600 GRT (number/in thousands of gross tons)
3Sep39 2,999/17,784
30Sep40 3,75721,373
30Sep41 3,608/20,552
31Dec41 3,616/20,693

Thus, despite the 'success' of the U-Boat force in 1940 (relative to its performance in 1941 and 1942) it had no appreciable effect in reducing the size of the British merchant fleet.

Numbers of ships arriving and losses in North Atlantic convoys inbound to Britain (ships arriving/losses)
1939 700/5 (7.1%)
1940 5,434/133 ((2.5%)
1941 5,923/153 (2.6%)
1942 4,798/80 (1.7%)
1943 5,667/87 (1.5%)
1944 7,410/8 (0.1%)

The operational U-Boat force from 1943-1945 never approached a "steady 400-500 boat." Rather, during 1942 the peak strength of boats assigned to combat flotillas (including those under repair for combat-damage and breakdowns, but excluding those assigned to school flotillas, experimental projects, or otherwise retired from combat) was 202, during November. The low in 1942 was 89 in January. The average monthly strength during 1942 was 143.83. The strength of the force peaked in May 1943 at 237. It had declined to a low of 159 by November. Average monthly strength during 1943 was 197.58. The peak strength during 1944 was 168 in February, the low was 146 in November. Average monthly strength in 1944 was 157.83. The peak strength in 1945 was April with 165, the low was May with 134, prior to the surrender. <http://www.onwar.com/ubb/smile.gif>

At that, these were much better than 1939 (average of 19.5 monthly), 1940 (average of 18.75 monthly) and 1941 (average of 47.5 monthly). OTOH, the 'bang for their buck' was probably highest in 1940, which was also arguably the U-Boats most 'successful' year in terms of ships sunk per patrol and U-Boats lost per ship sunk (see my previous reply).

 

[syscom3]

Great info!!!!!

Thanks.

 

[Udet]

syscom:

Also you could get your hands on Clay Blair´s "Hitler´s U-boat War", a cumbersome work by the way.

The only aspect of his work that is worth the rescue is precisely that of presenting summaries of U-boats commissioned, deployed and lost, not to mention what seems to be a very comprehensive and detailed presentation of allied shipping production.

However, Blair´s work is perhaps the cleanest, leanest and most horrific example of what the drunken mind of the victor can spawn.

The author had serious issues against the Germans by the time he embarked on the effort of doing his book; such issues reflect throughout the entire book: German U-boats were complete pieces of crap; U-boat commanders and crews were nothing but amateurs or aficionados at best -ahh, and also they were not "supermen", making fun of those German submariners who were captured and killed in combat against allied escorts-; German intelligence officials were stupid whereas the role of Allied intelligence hardly represented an effort beyond playing the "cat vs. mouse" game and a very long blah, blah, blah...

Also the guy was highly disrispectful of Admiral Karl Dönitz in almost every sense. He portrays the Admiral as a confused, overwhelmed nearly incompetent commander. He chopped off Dönitz in a completely biased manner.

Putting aside the commanding skills of Karl Dönitz -he was FAR from being the type of commander depicted by that author-, and for what is worth, we talk about a man, that being at the top of the political and military structures of a world power, lost his ONLY two sons in combat; unlike some desk warriors of the present-day world who evaded serving in the military in times of war, the sons of the Admiral did not pull any "strings" to save themselves from the perils of war nor Admiral Dönitz did anything to preserve his boys.

If people -like Clay Blair- will not respect that at minimum, then my sympathies for persons like that will not be allowed the length of a table.

 

[syscom3]

Thanks Udet.

I have his book on US submarine operations, and he pulls no punches in criticising the efforts of the USN Pacific commanders.

 

[drgondog]

Got this off some BB somewhere, sometime.

1939:
Allied and Neutral ship tonnage sunk by German and Italian submarines (#ships, GRT)
Sep39 48/178,621
Oct39 33/156,156
Nov39 27/72,721
Dec39 39/101,823
Tot39 147 (36.75/month)/509,321 (127,330.25/month)

British merchant ship construction capacity from 1939-1941 did not exceed 1.2 million GRT per year.
US merchant ship construction in 1939 was 0.242 million GRT.


At that, these were much better than 1939 (average of 19.5 monthly), 1940 (average of 18.75 monthly) and 1941 (average of 47.5 monthly). OTOH, the 'bang for their buck' was probably highest in 1940, which was also arguably the U-Boats most 'successful' year in terms of ships sunk per patrol and U-Boats lost per ship sunk (see my previous reply).

Al - this is best summary I have seen so far and adds some facts to my own speculation.

I am inclined to believe that Britain a.) could not have increased shipping tonnage at expense of anti-sub, or b.) could not have sustained Britain in context of fuel and food through 1943 - absent some amazingly efficient breakthroughs in detection and sub sinking technologies.

I don't know how important the 50 Lend Lease destroyers were to Britain, but I do know how important our ship building and steady stream of supplies were to marginally overcome the Atlantic threat in 1943 - after 18 months of our own dedication. I still do not know how Britain would have kept supply chain going from Canada or Africa/Middle East

What are your thoughts about Britain being able to fight Germany if we had stayed completely neutral and Japan attacked only Britain (and de facto Netherlands in Borneo, etc)?

 

[Civettone]

Yeah, that was a great post, Al! I saved it on my HD!

What are your thoughts about Britain being able to fight Germany if we had stayed completely neutral and Japan attacked only Britain (and de facto Netherlands in Borneo, etc)?

That's a bit difficult to imagine. First, it would require bypassing the Philippines which is basically asking for trouble: the Americans would reinforce the islands and hold the ability to cut off the Japanese supplies.
Second, the Dutch Indies were safeguarded by the Americans. They had an agreement with the Dutch to intervene if the Japs invaded the islands.

Kris

 

[Glider]

I am inclined to believe that Britain a.) could not have increased shipping tonnage at expense of anti-sub, or b.) could not have sustained Britain in context of fuel and food through 1943 - absent some amazingly efficient breakthroughs in detection and sub sinking technologies.

I don't know how important the 50 Lend Lease destroyers were to Britain, but I do know how important our ship building and steady stream of supplies were to marginally overcome the Atlantic threat in 1943 - after 18 months of our own dedication. I still do not know how Britain would have kept supply chain going from Canada or Africa/Middle East

What are your thoughts about Britain being able to fight Germany if we had stayed completely neutral and Japan attacked only Britain (and de facto Netherlands in Borneo, etc)?

I admit this is the stuff of nightmares. If I had to guess everything would have to be concentrated on the Atlantic and the Med, Atlantic for the Food and supplies, the Med for the oil.

Bomber Command would have to concentrate on the U Boat yards which were to a shocking degree left alone. Coastal Command would have had to been given the long range bombers that they desperately asked for to close the mid atlantic gap, but denied at the time. Of all the trends that made the difference in the Battle of the Atlantic air cover was the largest.

Far East and Burma would have to be abandoned and with it India. Could the British succeed, probably, but only if the powers that be had the strength to make the above decisions.
The question is would they make the calls and to be honest, politically I doubt it and that, is the nightmare.

 

[Civettone]

What was the combat value of those bombers for Coastal Command back in 1942?

Why would India have to be given up? Japan didn't have the logistics to invade and occupy India. As long as they were fighting in the mountains and forests of Burma they did allright but India is too much for the Japs.

Kris

 

[syscom3]

What was the combat value of those bombers for Coastal Command back in 1942?

Why would India have to be given up? Japan didn't have the logistics to invade and occupy India. As long as they were fighting in the mountains and forests of Burma they did allright but India is too much for the Japs.

Kris

I agree about India being too much for the IJA. Perhaps control India up to the Ganges river, but thats about it.

 

[Glider]

The mere presence of an aircraft would make a U Boat submerge and that alone significantly increased the chances of the convoy getting through. They were of course slower and had reduced the chances of them recharging their batteries.
The aircraft used in Coastal Command at the time were obsolete bombers, Whitley, Hampden plus Hudsons and a few Wellingtons. Those that could have been used are Sterlings and Halifax's. With a reduced bombload and additional fuel tanks they could have gone a long way to closing the gap.

The Sterling in particular would have been useful as it didn't have a high operating ceiling which isn't a problem on A/S duties and it was very manoeverable for a plane of its size. In addition it had bomb cells in the wing which leant themselves to the use of fuel tanks.

However, as I said at the start the chances of Bomber Command releasing these aircraft were slim at best.

 

[Udet]

Al - this is best summary I have seen so far and adds some facts to my own speculation.

I am inclined to believe that Britain a.) could not have increased shipping tonnage at expense of anti-sub, or b.) could not have sustained Britain in context of fuel and food through 1943 - absent some amazingly efficient breakthroughs in detection and sub sinking technologies.

I don't know how important the 50 Lend Lease destroyers were to Britain, but I do know how important our ship building and steady stream of supplies were to marginally overcome the Atlantic threat in 1943 - after 18 months of our own dedication. I still do not know how Britain would have kept supply chain going from Canada or Africa/Middle East

What are your thoughts about Britain being able to fight Germany if we had stayed completely neutral and Japan attacked only Britain (and de facto Netherlands in Borneo, etc)?

Jackpot hit.

This is something i´ve been saying for a while now.

Let´s project some facts to assess the significance of the military aid that came from the USA:

If the Soviets had not received, say, the hundreds of thousands of Lend Lease military vehicles (Studebackers) that proved essential to have a large number of mechanized army units deployed in combat operations, they would have had to produce a similar type of vehicle all by themselves, with the predictable consequences:

- Gearing up the soviet military industry to a level that would prove adequate and sufficient to produce all necessary war items (tanks, artillery, aircraft, military transports, etc.) for deployment in such numbers as we know they had for 1944 and 1945 would have taken a significantly longer period of time...what about a year and a half or even more than two years, possibly more.

First point acknowledged, other predictable effects would be:

- They would have produced smaller numbers of other important items such as T-34 tanks and IL-2 ground attack planes for the 1942/43/44/45 period.

- Producing a number of military vehicles in such quantity to mechanize the number of army units records show they had for 1944/45 becomes impossible, depriving thus the Red Army of the high mobility observed during "Operation Bagration" and subsequent offensive operations in the east; who knows, without LL chances are Bagration does not even happen.

The Soviets would of been in such position to decide whether to find some sort of balance in the military production, or to devote a greater effort to produce some specific war items in large numbers at the expense of others that on the record appear to have been essential in the soviet war effort.

So if you are running your own Hamburguer shop and you found yourself a business partner that will timely deliver all pickles, tomatoes and onions sliced, all lettuce chopped, buns baked and fries cut and prepared to fall into the boiling oil, leaving you with the sole responsiblity of making the patties you have to believe your time at the shop will be much easier and it will take you less time to assemble the burguers claimed by your hungry clients.

As easy as this and the same condition can be applied in the British case.

Could Great Britain have produced something like ~2,700 Liberty Ships without directly affecting the production of other war vessels, especially destroyers, corvettes, and sloops which were essential to combat U-boats?

The answer should be a "no". Without the entrance of the U.S. into the war in Europe, then the Great Britain must produce war vessels to replace those already lost in combat -which as i presented here were just too many prior to the end of 1941-, plus merchant shipping tonnage to ensure supply lines remain open or at least secured in such level to permit the flow of essential materials and goods to sustain the level in the fight.

Could Great Britain allocate Royal Navy units in distant areas such as the Caribbean to ensure safety of tankers that would transport oil all the way to Great Britain without affecting its presence in the Mediterranean and North Atlantic?

Here too the answer should be a "no". Following the loss of Singapore and Burma, and the ugly battering they had to swallow during the one and only major Japanese naval operation in the Indian Ocean, and the timid and irresolute response in such areas, oil supply for England was severely threatened.

Since the USA is neutral, and in view of their need for oil to maintain the war machine on the move, Great Britain must look for oil in areas far from Japanese threat...possibly the Caribbean/Gulf of Mexico sectors.

As it did occur, it was the U.S. Navy who embarked on the task of fighting the U-boat menace in the Gulf of Mexico/Caribbean; losses of tankers to German submarines were very high in the beginning. The U.S. Navy was the one who defended the trench in those critical sectors.

 

[syscom3]

....
Could Great Britain allocate Royal Navy units in distant areas such as the Caribbean to ensure safety of tankers that would transport oil all the way to Great Britain without affecting its presence in the Mediterranean and North Atlantic?

Here too the answer should be a "no". Following the loss of Singapore and Burma, and the ugly battering they had to swallow during the one and only major Japanese naval operation in the Indian Ocean, and the timid and irresolute response in such areas, oil supply for England was severely threatened.

Since the USA is neutral, and in view of their need for oil to maintain the war machine on the move, Great Britain must look for oil in areas far from Japanese threat...possibly the Caribbean/Gulf of Mexico sectors.

As it did occur, it was the U.S. Navy who embarked on the task of fighting the U-boat menace in the Gulf of Mexico/Caribbean; losses of tankers to German submarines were very high in the beginning. The U.S. Navy was the one who defended the trench in those critical sectors.

I would suppose that the US maintained a semi-belligerent status with the Germans. Even if war was not declared, their was no love or sympathy for Berlin.

I would say the US maintains a defensive zone in the Atlantic out to the middle with a "no warning" given to any U-Boat found. The Germans would also flatly be warned not to send U-Boats into the Carrib or Gulf.

This would aid the RN somewhat. Enough for the UK to survive? Yes. To buildup the armies and prepare for an invasion on the scale of Overlord and Dragoon? No!

 

[Glider]

Could Great Britain have produced something like ~2,700 Liberty Ships without directly affecting the production of other war vessels, especially destroyers, corvettes, and sloops which were essential to combat U-boats?

The answer should be a "no".

Agreed

Without the entrance of the U.S. into the war in Europe, then the Great Britain must produce war vessels to replace those already lost in combat -which as i presented here were just too many prior to the end of 1941-, plus merchant shipping tonnage to ensure supply lines remain open or at least secured in such level to permit the flow of essential materials and goods to sustain the level in the fight.

This bit I disagree with. The prodiction of escort vessels which clearly was the key in the Atlantic would have been sufficient. By taking the steps mentioned in my earlier posting I believe it would have helped.

Could Great Britain allocate Royal Navy units in distant areas such as the Caribbean to ensure safety of tankers that would transport oil all the way to Great Britain without affecting its presence in the Mediterranean and North Atlantic?

Here too the answer should be a "no".

Totally agree but we didn't need to as long as we held the Med

As it did occur, it was the U.S. Navy who embarked on the task of fighting the U-boat menace in the Gulf of Mexico/Caribbean; losses of tankers to German submarines were very high in the beginning. The U.S. Navy was the one who defended the trench in those critical sectors.

You are correct, but not without the help of the RN. A number of British escorts were given to the USN in reverse lend lease to help with this task. Of course the numbers were tiny compared to what the USA later gave the UK, but they did tide the USN over until there own production built up.

 

[drgondog]

I would suppose that the US maintained a semi-belligerent status with the Germans. Even if war was not declared, their was no love or sympathy for Berlin.

I would say the US maintains a defensive zone in the Atlantic out to the middle with a "no warning" given to any U-Boat found. The Germans would also flatly be warned not to send U-Boats into the Carrib or Gulf.

This would aid the RN somewhat. Enough for the UK to survive? Yes. To buildup the armies and prepare for an invasion on the scale of Overlord and Dragoon? No!

Syscom - I would respectfully disagree your middle point.

My take is that while we might stay 'semi-belligerent' I don't see Roosevelt surviving politically if we committed to taking the loss in treasure and lives implied in the Battle of Atlantic, without declaring war.

He could have, by executive order, instructed Merchant Marine and USN to sail forth and supply Britain - but absent Pearl Harbor would not have the backing of even the Democrat, much less Republican, Congress to declare war. The Lend Lease Act was a political dogfight as it stood.

I believe that (sustained shipping and war materials) would have required the will of the American people and the will was not there until Pearl Harbor.