Causes and effects of U Boat war

[Jon G.]

good points :I agree that the only effect the UBoat war could have ,was to delay an Allied build-up.But the build-up was not only dependent from the dislodging of the UBoats,but also from the amount of US forces that were operational .Even,if in june 1942 the battle of the Atlantic had ended as in june 1943,an allied attack on occupied Europe would be very risky,because the Allies did not have the necessary forces .

Thanks, but then we can also agree that the U-Boat war wasn't lost for the Germans in December 1941, and that the submarine campaign wasn't any more hopeless than the rest of Germany's war by the time the Americans entered the fight?

[RichTO90]

If the figures of Wiki are reliable (and,that's always a problem),the Norwegian merchant fleet was worth 4 million of tons in 1940.

The Norwegian Merchant fleet in Allied/German hands consisted of:

233/12 tankers
11/1 whale factories
433/84 motor and steam vessels of 2,500 DWT or greater
193/142 motor and steam vessels of 500-2,499 DWT

The Germans retained most of the coastal fishing fleet while 107 whalers made it into Allied hands.

Cheers!

[Jon G.]

More numbers...

Size of merchant fleet as of September 1. 1939/Tonnage captured by Germans in 1940 (in %)

Belgium 384,000/118,092 (30.8%)

Holland 2,616,000/486,196 (19.2%)

Denmark 1,130,000/435,541 (40.9%)

Norway 3,308,000/942,027 (28.0%)

Figures in DWT and for dry cargo ships only! if you add in the tankers, as per Rich's post above, then the Norwegian contribution of ships to the Allied side of the scales becomes even more important.

[ljadw]

John G.and Rich.:thank you both for these -as usual- very useful informations .

[RichTO90]

Figures in DWT and for dry cargo ships only! if you add in the tankers, as per Rich's post above, then the Norwegian contribution of ships to the Allied side of the scales becomes even more important.

Excellent Jon. I have not seen so exact figures for anthing other than the Norwegian fleet. Where did you find them? And, yes, very important, especially I suspect the tankers of Royal Dutch Shell.

[hagen]

Your suggestion is an alternative ,but,not a viable one .
You are free,..to deny the facts,but the facts are,unless you can prove the opposite,at NO moment,between september 1939 and somewhere in the summer of 1943,the UBoats did constitute a mortal danger for the allies :at no moment,the UBoats could force Britain to give up .

It might be easy to think the war was already won in 1940 but it should be remembered that Churchill was a worried man throughout this period: the only thing that ever really frightened me during the war was the U-boat peril [Their Finest Hour p529].

The records show:

Losses: Shipping tonnage U boats
1939 755,237 009
1940 3,991,641 023
1941 4,328,538 035
1942 7,790,697 086
1943 3,220,137 237
1944 1,045,629 242
1945 411,127 151
Source: Terraine - Business in Great Waters

I believe March 1943 is normally seen as the crisis and May 1943 as salvation.

Now we have to take consider:
(1) How to take out of these numbers the impact of the USA entering the war
(2) How to add in the impact of increased German resource allocation to maritime and air power
(3) How to deal with the economic bankruptcy to which Britain was approaching

It was only by the narrowest of margins … the U-boat campaign failed to be decisive in 1941. [British Intelligence in the Second World War Hinsley p169.]

My proposal is to add pressure to close that margin; I suggest it might have been sufficient.

[Jon G.]

Excellent Jon. I have not seen so exact figures for anthing other than the Norwegian fleet. Where did you find them? And, yes, very important, especially I suspect the tankers of Royal Dutch Shell.

Thanks. I got the figures from C. B. A. Behrens' book Merchant Shipping and the Demands of War p 112, an excellent book out of the HMSO series.

More goodies from the same book, p 23:

1/Neutral-flagged tankers (only!) as of Sept. 1 1939

No. of ships/DWT

Belgian 9/94,000

Dutch 107/758,000

Danish 13/163,000

Norwegian 268/3,194,000

...as can be seen, tankers were something of a Norwegian specialty, making up close to half of total Norwegian merchant tonnage measured by DWT.

2/Canadian-registered merchant shipping as of Sept. 1 1939 (not including Great Lakes shipping)

No. of ships/DWT

59/307,000

...of which tankers:

12/134,000

[mescal]

And still more numbers ...

Here are the tanker figures found in Clay Blair's Hitler's U Boat War Vol1, Appendix 17.

First the existing stock at the beginning of the war and the new construction of USA & British empire up to late 1942

Tankers1.jpg

And next the losses :

Tankers2.jpg

During the whole year 1943, only 48 tankers were sunk, while 245 were built by USA & British Empire.

[Jon G.]

...
Now we have to take consider:
(1) How to take out of these numbers the impact of the USA entering the war
(2) How to add in the impact of increased German resource allocation to maritime and air power
(3) How to deal with the economic bankruptcy to which Britain was approaching
...

The problem is that if you 1/remove the effects of the US entering the war from the equation, you also remove a lot of the tonnage the U-Boats sunk, especially in 1942. 2/ might be dealt with by more British/Allied resources devoted to fightning the U-Boat menace - say, by giving RAF Coastal Command four-engined aircraft earlier, and the historical answer to 3/ was the Lend-Lease Act.


Thanks for more numbers, mescal. A bit confusing, though, that we're using different tonnage denominators

[ljadw]

Your suggestion is an alternative ,but,not a viable one .
You are free,..to deny the facts,but the facts are,unless you can prove the opposite,at NO moment,between september 1939 and somewhere in the summer of 1943,the UBoats did constitute a mortal danger for the allies :at no moment,the UBoats could force Britain to give up .

It might be easy to think the war was already won in 1940 but it should be remembered that Churchill was a worried man throughout this period: the only thing that ever really frightened me during the war was the U-boat peril [Their Finest Hour p529].

The records show:

Losses: Shipping tonnage U boats
1939 755,237 009
1940 3,991,641 023
1941 4,328,538 035
1942 7,790,697 086
1943 3,220,137 237
1944 1,045,629 242
1945 411,127 151
Source: Terraine - Business in Great Waters

I believe March 1943 is normally seen as the crisis and May 1943 as salvation.

Now we have to take consider:
(1) How to take out of these numbers the impact of the USA entering the war
(2) How to add in the impact of increased German resource allocation to maritime and air power
(3) How to deal with the economic bankruptcy to which Britain was approaching

It was only by the narrowest of margins … the U-boat campaign failed to be decisive in 1941. [British Intelligence in the Second World War Hinsley p169.]

My proposal is to add pressure to close that margin; I suggest it might have been sufficient.

about the losses of shipping tonnage,I have other figures :some 2.1 million for 1941 (source:Brennecke:the turn in the UBoatWar,p52)
About the impact of increased German resource allocation to maritime and air power,that would mean less resource for the fighting in the east,less LW strength in the east,the Mediterranean,and also for the defense of the Reich .
249 submarines on 1 january 1942,had as result 55 in the Atlantic,of which 22 on patrol.
400 submarines in march 1943,had as result 182 ,of which 70 on patrol .
Last point:more UBoats will not automatically result in more allied shipping losses,because,the Allies will increase their ASW measures :70 on patrol will not sink 3 times more tons than 22 on patrol .That's the flaw of your argument :you are giving the Germans more resources,without doing the same for the Allies .

[hagen]

about the losses of shipping tonnage,I have other figures :some 2.1 million for 1941 (source:Brennecke:the turn in the UBoatWar,p52)
About the impact of increased German resource allocation to maritime and air power,that would mean less resource for the fighting in the east,less LW strength in the east,the Mediterranean,and also for the defense of the Reich .
249 submarines on 1 january 1942,had as result 55 in the Atlantic,of which 22 on patrol.
400 submarines in march 1943,had as result 182 ,of which 70 on patrol .
Last point:more UBoats will not automatically result in more allied shipping losses,because,the Allies will increase their ASW measures :70 on patrol will not sink 3 times more tons than 22 on patrol .That's the flaw of your argument :you are giving the Germans more resources,without doing the same for the Allies .

2.1m might be a reference to the North Atlantic U-boat war or something like that but in which case it misses the importance of total tonnage. What is not clear is how much extra effort the British might have been able to make given that this was a life and death struggle. I am increasing German resources as a matter of policy but are the British in a position to increase theirs?

We can agree that it would mean less resources for the Eastfront but I would not start that until Britain had been beaten and it would give time for a new generation of tanks to be developed and produced. Of course the Soviets might get even further ahead with the T34 but that is a different debate! Aerial defence of the Reich need not be reduced and was of limited impact at this stage in the war. The other active war fronts need not necessarily be changed.

Of course, it is all hypothetical and to a significant extent would be overridden by the psychology of Hitler. However, had he been more willing to listen to his advisers I fear we might ALL have been learning German at school.

[berrek]

Your suggestion is an alternative ,but,not a viable one .
You are free,..to deny the facts,but the facts are,unless you can prove the opposite,at NO moment,between september 1939 and somewhere in the summer of 1943,the UBoats did constitute a mortal danger for the allies :at no moment,the UBoats could force Britain to give up .

It might be easy to think the war was already won in 1940 but it should be remembered that Churchill was a worried man throughout this period: the only thing that ever really frightened me during the war was the U-boat peril [Their Finest Hour p529].

The records show:

Losses: Shipping tonnage U boats
1939 755,237 009
1940 3,991,641 023
1941 4,328,538 035
1942 7,790,697 086
1943 3,220,137 237
1944 1,045,629 242
1945 411,127 151
Source: Terraine - Business in Great Waters

I believe March 1943 is normally seen as the crisis and May 1943 as salvation.

Now we have to take consider:
(1) How to take out of these numbers the impact of the USA entering the war
(2) How to add in the impact of increased German resource allocation to maritime and air power
(3) How to deal with the economic bankruptcy to which Britain was approaching

It was only by the narrowest of margins … the U-boat campaign failed to be decisive in 1941. [British Intelligence in the Second World War Hinsley p169.]

My proposal is to add pressure to close that margin; I suggest it might have been sufficient.

Even if one does not succeed in completely cutting off Brittain, ships sunk means cargoes lost and that always hurts your enemy. At the height of their success the U boats therefore seriously effected the allied war effort

[dcmatkins]

No. It repeated the mistake of fighting on two fronts, like it did in WW1.
Was Hitlers " living space" in the North Atlantic or Western Europe. Ultimately.

[ljadw]

I am not sure that I understand your post;the aim of the UBoat War was to eliminate Britain,and thus finish the war,as such,it failed .

[mescal]

Hagen,

Losses: Shipping tonnage U boats
1939 755,237 009
1940 3,991,641 023
1941 4,328,538 035
1942 7,790,697 086
1943 3,220,137 237
1944 1,045,629 242
1945 411,127 151

This table is the total of overall allied merchant losses, and includes all sources of damages (including marine casualties).
The U-boat force accounts for around 55% of this total.

Here are the figures for U-boats :
year --- #ships --- Tonnage (x1000 GRT)
1939 --- 114 --- 421
1940 --- 471 --- 2186
1941 --- 432 --- 2171
1942 --- 1160 --- 6266
1943 --- 463 --- 2586
1944 --- 132 --- 773
1945 --- 56 --- 281
Total --- 2828 --- 14687

Source : La bataille de l'Atlantique, Guy Malbosc.