"The survival rate of U-Boot crews was about 30% IIRC. As close to "Kamikaze" service as anything in the European Theater."

Early on in the war it was much better / quite low but later on as the Brits got squared away with ASDIC, the US entered the war, ENIGMA was cracked and a few other things, it became more suicidal - the rate was actually 75% so the survival rate was 25%.

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