In the first 6 months of the war 164 merchantmen were sunk by U-boats.
From mid March to the end of May 1940 Germany grouped her U-boats to cover the invasion of Norway.
From June to September 211 merchantmen were sunk by German U-boats.
In October 63 ships were sunk by U-boats. From October 18-20, 7 U-boats sunk 17 out of 34 freighters of convoy S.C.7 and 6 U-boats sunk 14 out of 49 ships from convoy H.X.79.
After 14 months of war the lossess of British, allied and neutral shipping amounted to a total of 471 ships sunk by Uboats
The German pocketbattleship Deutschland sank 3 ships on its first voyage.
The German Graf Spee sank 9 ships on its first and only voyage.
In May 1940 36 merchantmen were sunk by aircraft.
In the months of June, July and August a total of 73 ships were sunk by aircraft.
Total lossess by all causes to British, allied and neutral ships amounted to 1,026 ships lost by the end of October 1940.
Hipper, Admiral Scheer, Gneisenau and Scharnhorst all put to sea sinking or capturing 64 merchantmen. The success of Admiral Scheer's voyage ultimately led to the loss of Bismarck who failed to run the allied gauntlet and break out into the open sea.
200 merchantships were sunk in this period of time
69 merchantships were sunk in this period.
Total U-boat losses for 1941 were 53 boats compared with a figure of 42 in 1940.
May 1943
A total of 43 U-boats were sunk this month.
78 merchantmen sunk at a cost of 90 U-boats.
5 ships sunk at a cost of 24 U-boats.
37 ships sunk at a cost of 78 U-boats destroyed.
71 merchantmen sunk for a loss of 172 U-boats.