At 10.21 hours on 16 Dec 1943 the unescorted McDowell (Master Henry David Barrow) was hit by a Gnat from U-516 about 30 miles north of Aruba. The torpedo struck the port side at the screw, destroying the propeller and shaft and disabling the main and auxiliary engines and the steering gear. The ship settled by the stern rapidly, but the crew did not abandon ship. At 11.32 and 11.33 hours, two coups de grâce hit the disabled tanker. The first at the #7 port wing tank and the second at the #4 tank, this caused the ship to sink stern first within five minutes.

The ten officers, 35 crewmen and 28 armed guards (the ship was armed with one 5in, one 3in and eight 20mm guns) abandoned ship in five lifeboats and a raft. Two crewmen drowned. The boats were spotted by an aircraft about one hour later, the American steam tanker Fairfax picked up 63 survivors and landed them at Aruba. The chief cook died from injuries ashore on 22 December. About 16.00 hours, the remaining eight survivors were rescued by USS YMS-56 and landed at Aruba.