Although they lost World War II, the Nazis were more technologically advanced than their Allied rivals in multiple ways. Berlin’s problem was scale—and trying to do too much with too few resources.

The post-war narrative of the German U-boat efforts follows several stages: the first “Happy Time,” followed by the second “Happy Time,” and then utter destruction by the Allies. In reality, the ...

The German U-boat U-853 sank the last U.S. merchant ship sunk in WWII. Historian Tim Gray speculates that German U-boats may have entered Narragansett Bay before the U.S. officially entered WWII.