The importance of the battle of the Atlantic.

[JOC]

Vital food stocks, arms, and all kind of valuable supplies were shipped to Great Britain and to a slightly lesser extent the USSR by the Merchant Marines.
At 1st they took horrendous losses as they underwent this dangerous mission with the German U-bouts picking them off.
How important to the Allied and Soviet war efforts were these valuable imports? And how did the Allies develop the technology and tactics to combat the U-boat menace so as to win the battle of the Atlantic?

 

[MontyB]

Unlike Churchill I do not believe there really ever was a "U-Boat Menace" as at no stage did the U-Boat arm ever sink more than 5% of the tonnage in transit as such they were never really the threat the were painted as.

This topic is one that I hoped would have been adressed in the "Re-assessing WW2" thread as I think the propaganda of WW2 has been allowed to become fact.

Don't for a minute think I am questioning the bavery of the sailors who put to sea in either the ships or submarines but the fact of the matter is much like the Luftwaffe was never going to win the Battle of Britain and the Wehrmacht was never going to successfully invade Britain, the U-Boats were never going to starve Britain into surrender either, it is simply wartime propaganda.

 

[JOC]

The battle of the Atlantic was eventually won by the Allies in the later 1/2 of 43. Much of this was due to the vigorous code breaking going on by the Allies and the strengthening of the air escorts used to assist the convoys in their crossings. Britain being an Island nation was at risk of being cutoff by Germany's U-Boat menace. In March of 43 alone when Germany changed a key in it's enigma code 120 merchant and military ships were sunk worldwide, 82 ships of 476,000 tons in the Atlantic, while only 12 U-boats were destroyed.

 

[BritinBritain]

Unlike Churchill I do not believe there really ever was a "U-Boat Menace" as at no stage did the U-Boat arm ever sink more than 5% of the tonnage in transit as such they were never really the threat the were painted as.

This paints a rather misleading picture. Yes the loses were only 5% counting convoys that got through 100% unscathed after the U Boat menace was beaten. At the start of the war ships loses were far higher then 5% per convoy. From June until October 1940, over 270 Allied ships were sunk: this period was referred to by U-boat crews as "the Happy Time" ("Die Glückliche Zeit"). Churchill would later write: "...the only thing that ever frightened me during the war was the U-boat peril".

 

[I3BrigPvSk]

Of the three branches of the German military, the navy was the least prepared for war in 1939. Maybe the Germans wasted their limited resources on the surface fleet while Reader was the commander of the navy. When he was replaced by Donitz and he shifted the resources toward the u-boat fleet and after the defeat of France and the ability to base the u-boats in France the thread toward the supply lines increased a lot.

If the Kriegsmarine had been better prepared in the 1939-40 with more uboats, had they been able to starve the GB to submission?

 

[MontyB]

This paints a rather misleading picture. Yes the loses were only 5% counting convoys that got through 100% unscathed after the U Boat menace was beaten. At the start of the war ships loses were far higher then 5% per convoy. From June until October 1940, over 270 Allied ships were sunk: this period was referred to by U-boat crews as "the Happy Time" ("Die Glückliche Zeit"). Churchill would later write: "...the only thing that ever frightened me during the war was the U-boat peril".

I disagree even when broken down into a a month by month analysis there was no month that where more than 10% of the transatlantic convoys were attacked and of those the average number of ships lost was less than 10%/

Overall greater than 99% of all ships sailing to and from Britain reached their destination.

According to the Historian Clay Blair who wrote...

• "Hitler's U-Boat War: The Hunters, 1939-1942" 1996
• "Hitler's U-Boat War: The Hunted, 1942-1945" 1998

Unlike the Allies, the Germans were never able to mount a comprehensive blockade of Britain. Nor were they able to focus their effort by targeting the most valuable cargoes, the eastbound traffic carrying war materiel. Instead they were reduced to the slow attrition of a tonnage war. To win this, the U-boat arm had to sink 300,000 GRT per month in order to overwhelm Britain's shipbuilding capacity and reduce her merchant marine strength.


In only four out of the first 27 months of the war did Germany achieve this target, while after December 1941, when Britain was joined by the U.S. merchant marine and ship yards the target effectively doubled. As a result, the Axis needed to sink 700,000 GRT per month; as the massive expansion of the U.S. shipbuilding industry took effect this target increased still further. The 700,000 ton target was achieved in only one month, November 1942, while after May 1943 average sinkings dropped to less than one tenth of that figure.


By the end of the war, although the U-boat arm had sunk 6,000 ships totaling 21 million GRT, the Allies had built over 38 million tons of new shipping.


The reason for the misperception that the German blockade came close to success may be found in post-war writings by both German and British authors. Blair attributes the distortion to "propagandists" who "glorified and exaggerated the successes of German submariners", while he believes Allied writers "had their own reasons for exaggerating the peril"

Blair concludes:

"At no time did the German U-boat force ever come close to winning the Battle of the Atlantic or bringing on the collapse of Great Britain"

 

[BritinBritain]

I disagree even when broken down into a a month by month analysis there was no month that where more than 10% of the transatlantic convoys were attacked and of those the average number of ships lost was less than 10%/

When Churchill stated that the only time he was frightened was the U Boat peril was during the U Boat Happy Time. Perhaps the losses of ships were less then 10%, it is still a lot more then 5%

Overall greater than 99% of all ships sailing to and from Britain reached their destination.

Only if we included the convoys that got through with no losses whatsoever. Convoys that had high losses were the Russian convoys (Such as PQ17) and the convoys to resupply Malta.

 

[MontyB]

When Churchill stated that the only time he was frightened was the U Boat peril was during the U Boat Happy Time. Perhaps the losses of ships were less then 10%, it is still a lot more then 5%



Only if we included the convoys that got through with no losses whatsoever. Convoys that had high losses were the Russian convoys (Such as PQ17) and the convoys to resupply Malta.

If 90% of transatlantic convoys were not attacked at all and the 10% that were attacked were not all attacked by uboats (some by ship most by air) then i think it is accurate to say the uboat threat was over rated.

Most of the arctic convoys were attacked by surface ships and aircraft not submarines.

In my opinion the Uboat threat was more about its possible presence than its actual presence, in other words it was similar to "Tiger fever" was on land.

 

[lljadw]

One should not talk about how much GRT was lost,but about how much GRT arrived and about how much GRT was needed .

Reality is that Britain never was in serious danger: not on food,not on fuel, ....

Reality is that Britain was winning the war against the U Boats fro the first day on:at the end of 1940 Britain had gained more GRT than it had lost by the U Boats : the U Boats were expelled from the coasts to the Atlantic where to look for a convoy was looking for a needle in a haystack.

 

[BritinBritain]

If 90% of transatlantic convoys were not attacked at all and the 10% that were attacked were not all attacked by uboats (some by ship most by air) then i think it is accurate to say the uboat threat was over rated.

What surface ships were a threat to Atlantic convoys after the sinking of the Graff Spee and Bismark? I would suggest that most convoy attacks in the Atlantic were by U boat.

Most of the arctic convoys were attacked by surface ships and aircraft not submarines.

Don't agree. This is from National Archives:-http://www.nationalarchives.gov.uk/education/worldwar2/theatre-assets/atlantic/pdf/a-battle-of-the-atlantic.pdf

In my opinion the Uboat threat was more about its possible presence than its actual presence, in other words it was similar to "Tiger fever" was on land.

As I stated in an earlier post, Churchill was worried about the U Boats during their ""Happy Time.""

 

[MontyB]

What surface ships were a threat to Atlantic convoys after the sinking of the Graff Spee and Bismark? I would suggest that most convoy attacks in the Atlantic were by U boat.

After the Graff Spee there was a number of commerce raiders that operated in the Atlantic, for example the auxiliary cruisers Stier, Michel and Atlantis.

I agree that most attacks were by Uboat but I suspect the Luftwaffe would have come in second in terms of tonnage sunk.

 

[lljadw]

55 % of the merchant navy losses were caused by U Boats

 

[lljadw]

The following figures are from the AHF (thread: causes and effects of U Boat War)

1) British merchant fleet on 1 september 1939 : 18.7 million GRT

2) Til 31 december 1941 this was increased by

the production of the UK yards

the production of the Empire

a big part of thr French merchant fleet after France was out in june 1940

a big part of the Italian and German merchant fleet which was captured in the beginning of the war

the aid of Greece and Liberia

the majority of the merchant fleets of Belgium (268000 GRT),Holland (2.18 million), Denmark (695000),Norway (2.36 million) : dry-cargo only;to this must be added 4.2 million GRT of tankers


3)the losses were ( by U Boats only) :

1939: 420000 GRT

1940: 2186000 GRT

1941: 2.171.OOO GRT

3) The conclusion is that on 31 december 1941 Britain had obtained more GRT than was lost by the U Boats (at least 9.7 million against a loss of 4.7 million) and that the U Boats had failed into their attempt / mission to starve Britain and to force it to surrender .

For this there were also other reasons,as : the very small number of U Boats sailing in the zone of operations ,and ,maybe more essentially, the fact that the U Boats were as moles : blind and very primitive : most convoys and ships not sailing in convoy were not detected and most of those who were detected were not attacked and most of those who were attacled were not sunk:

only 10 % of the big trans-atlantic convoys were attacked and their losses were 10 % ,which means that only 1% of the ships sailing in convoys were lost by U Boats .

 

[JOC]

Between 1939-1945 German shipyards launched ~ 1200 U-boats, of which ~ 800 were destroyed during the war, 632 at sea.

One important aspect of the Battle of the Atlantic was the fact that this was a drain on German resources. Having to at the same time fight major land (and air particularly in the case of the Allies) wars against the USSR and the Allies having to maintain a naval presence as well as submarine pens further drained Germany’s more limited resources seeing as it was primarily a land based power.