U-Boat 977, captained by commander Heinz Schaeffer, chose not to surrender at the end of World War II. He and most of his crew feared their fate at the hands of the victorious Allies, as predicted by Goebbels who amongst other things had made good propaganda use of the Morgenthau Plan to turn Germany into a "goat pasture".
Instead, 31 of the crew took the submarine to Argentina. Those who chose to stay behind were put ashore in Norway.
In its final voyage U-977 spent 66 days traveling continuously submerged, from May 10 to July 14. The underwater voyage was made blindly, due to a periscope mishap. The wartime underwater record was second only to the 68 days of U-978.
With one third of the trip completed, but suffering in the diesel-fume filled and molding submarine, the crew finally resurfaced and spent the remainder of the voyage on the surface.
On Aug. 17, 1945 the crew of U-977 reached Mar del Plata Harbor in Argentina, and were subsequently sent to the United States to be held in POW camps.
U.S. authorities feared that Hitler had fled using the submarine, and was hiding somewhere in South America.
The U-977 was later towed to Boston and turned over to the US Navy on 13 Nov, 1945. That same week, she was sunk off the Massachusetts coast during torpedo trials by the American submarine USS Atule.
Schaeffer wrote a book; U-977 - 66 Tage unter Wasser which was translated into English in the early 1950's and whose latest English edition was in 2005.