HMS STRATAGEM (Lt C Pelly) sailed from Trincomalee on 10 November 1944 with orders to patrol in the Malacca Staits. Pelly had joined just before sailing to replace STRATAGEM appointed Commanding Officer, Lt Cdr M Willoughby, who was unwell.

On 18 November 1944, the Commanding Officer fired a salvo of three torpedoes at an escorted Japanese convoy and one hit was seen on the NICHINAN MARU. After being counter-attacked by an escort, a single torpedo was fired from the stern tube which hit and sank the target.

On 22 November 1944, a Japanese aircraft spotted HMS STRATAGEM and passed the position to a destroyer which made a depth charge attack. The submarine was severely damaged, began to flood and, although attempts were made to surface the submarine, they were unsuccessful, and STRATAGEM sank to the bottom. She suffered flooding but 14 men, including the torpedo officer (Lt Douglas), managed to get into the torpedo compartment. Ten of these men managed to escape (the submarine was in shallow water) and 8 survived the experience. Picked up by the Japanese destroyers, they were treated brutally, being clubbed and beaten.

These prisoners were returned to Singapore and, eventually, to Japan where they were subjected to interrogation and further harsh treatment. The STRATAGEM survivors were eventually liberated on 26 August 1945. Of the eight picked up, only 3 survived to be freed, the others being executed by their captors.