Crossing the Atlantic in November 1942. U.S. Navy via Commons

Germany had the naval advantage, easily capturing weakly defended commerce ships despite suffering huge losses. From December 1941

American B-25 Mitchell and B-24 Liberator bombers attack a German U-boat

An estimated 2,700 merchant ships and 800 of Germany's 1,100 U-boats sank between 1939 and 1945.

Allied and Axis sailors had very different sea experiences, with the latter in particular peril. U-boats were not very comfortable.

Blazich claims that destroyer duty was “equally chilly, damp and nauseating” for both sides.