At 18.15 hours on 20 Sep 1942 the Silver Sword (Master Clyde Wellington Colbeth) in convoy QP-14 was hit on the port side by two torpedoes from U-255 in the Greenland Sea. The first struck in the bow and the explosion knocked down the forward part of the bridge, while the second hit the stern, blowing off the stern post, the propeller and the rudder and caused the after magazine to explode. The seven officers, 29 crewmen, twelve armed guards (the ship was armed with one 4in, two .50cal and two .30cal guns) and 16 passengers abandoned ship in two lifeboats and one raft. 55 survivors were picked up by the British rescue ship Rathlin and nine by the Zamalek and taken to Glasgow, but one oiler later died of wounds aboard. They were repatriated on the British passenger ship Queen Mary, arriving in Boston on 15 October.
The wreck of the Silver Sword was shelled after 30 minutes by HMS Worcester (D 96) (LtCdr W.A. Juniper, DSO, RN) and sank at 19.00 hours.

The passengers were survivors from ships lost in the ill-fated convoy PQ-17: 15 survivors from Honomu and one survivor from the American steam merchant Peter Kerr, which had been sunk by German aircraft on 5 July.