At 01.32 hours on 5 May 1942 the unescorted and unarmed Munger T. Ball (Master Karl Ragnar Olsen) was hit by one torpedo from U-507 while steaming at 10 knots on a non-evasive course about 80 miles northwest of Dry Tortugas Island. The torpedo struck on the port side amidships, followed by a second torpedo 30 seconds farther aft near the engine room. The tanker burst into flames after the first hit and prevented the launching of lifeboats. Only four crewmen of the eight officers and 26 crewmen on board managed to abandon the ship by jumping overboard and swimming away before burning gasoline spread on the water, trapping many men on the tanker. The burning tanker sank about 15 minutes after the second hit. The four survivors swam to a life raft, were picked up about four hours later by the Katy and landed at Key West, Florida.