information:filtering, stylistic:tone, information:extraction
Outcomes

The Germans failed to stop the flow of strategic supplies to Britain. This failure resulted in the build-up of troops and supplies needed for the D-Day landings. The defeat of the U-boat was a necessary precursor for accumulation of Allied troops and supplies to ensure Germany's defeat.

Between 1939 and 1945, some 72,200 Allied naval and merchant seamen died. The Germans lost approximately 30,000 U-boat sailors killed, three-quarters of Germany's 40,000-man U-boat fleet.