U-464 was lost on her first patrol. As a supply boat, she avoided combat. On August 20, 1942, south-east of Iceland, she was attacked by a US Catalina aircraft. Although the aircraft dropped all its bombs without sinking the boat, two crewmen were killed during the attack, and the boat was left unable to dive. While U-464 could still make some eight knots, it was only a matter of time before another aircraft or ship would find and destroy her. Harms spotted a fishing vessel nearby and decided to scuttle U-464.
The Icelandic trawler Skaftfellingur sighted for the distressed U-boat and began rescue operations. The seven-man Icelandic crew placed the 52 German survivors in the bow of their trawler and guarded them with a machine gun on the bridge. Later that same day the trawler rendezvoused with a pair of British destroyers and turned the German prisoner over to them.
This story was unacceptable to the Kriegsmarine, which published a slightly edited version: the U-boat crew boarded the trawler by force, captured its crew, and was heading for Germany when they were intercepted by the destroyers and taken prisoner.
In July 1999 a squadron of Deutsche Marine submarines visited Reykjavik to honor the Icelandic seamen who rescued (or were subdued by) the U-boat crew.