Very interesting, Sokal. I can't imagine what it would have been like to be crewing a freighter in the Atlantic or the North Sea back then. The German surface vessels were bad enough, but the Wolfpack was all over the place—they sank numerous ships along the U.S. coastline.
Speaking of, if you ever get a chance to go to the Museum of Science and Industry in Chicago, they have an intact U-boat (U-505) that was one of the few whose captain didn't scuttle. That thing is crazy small (I'm kind of claustrophobic anyway), and even the Captain's quarters (a cot with a drape in front of it) made a closet look like a ballroom.