"U-659" attacked south-west of Iceland, at 21:10 on 10 September, and hit the 8,029-ton British tanker "Empire Oil" with two torpedoes, stopping her. All her crew of 53 survived, as the master, 12 crewmen and 6 gunners were picked up by HMCS "St. Croix", and 29 crewmen and 5 gunners by HMCS "Ottawa". At 01:47 the next day, "U-584" sank the drifting "Empire Oil" with two more torpedoes. After her strike "U-659" was counter-attacked by the convoy escorts and seriously damaged. She was forced to abort the patrol and returned to France.