At 18.55 hours on 6 May 1942, a lookout on the unescorted and unarmed Alcoa Puritan (Master Yngvar Adelstein Krantz) spotted a torpedo passing approximately 15 feet astern about 15 miles off the entrance to the Mississippi River. The master immediately ordered full speed and swung the ship to keep the U-boat dead astern to present as small a target as possible. U-507 surfaced and began to overtake the freighter which was running at 16.5 knots. Five minutes the U-boat began to shell the ship from a distance of one mile. In 40 minutes, about 75 rounds were fired, scoring about 50 hits and disabling the steering gear. Two of the crew members suffered minor shrapnel injuries. The crew of ten officers, 37 crewmen and seven passengers abandoned ship in one lifeboat and two rafts. At 19.43 hours, a torpedo was fired which struck below the #4 hatch and caused the ship to sink stern first in eight minutes. U-507 then approached the survivors and a German officer with a megaphone shouted: Sorry we can´t help you - hope you get ashore. and waved as the U-boat sailed away. All hands were picked up by USCGC Boutwell (WPC 130) the same day and landed at Burrwood, Louisiana, after they had been spotted by a patrol bomber.

The passengers were repatriated seamen from the American steam tanker T.C. McCobb, which had been sunk by the Italian submarine Pietro Calvi (Olivieri) about 600 miles off British Guiana on 31 March 1942.