At 21.37 hours on 29 May 1942 the unescorted Allister was hit on the starboard side in the engine room by one of two torpedoes from U-504 while steaming on a non-evasive course at 11.8 knots about 54 miles south of Grand Cayman Island. The ship, only armed with one machine gun, broke in two and sank rapidly by the stern. Three men on watch below were presumably killed immediately and the master and eleven men were last seen launching a lifeboat which fouled davits and went down with the ship. The chief officer and seven men managed to rescue themselves on a raft that floated free. The U-boat surfaced after the attack and the Germans questioned the chief officer, asking the usual questions about name, tonnage, cargo and port of departure. They supplied the survivors with five gallons of water, ten cans of biscuits and dressing material and promised to signal their position before leaving. The survivors were picked up by an unknown ship after eight days and landed at Port au Prince, Haiti.