Having attended a promotion course in Portsmouth from May to August 1941, he was promoted to sub lieutenant on 10 October 1942 with seniority from 1 August 1941. He joined the crew of the sloop in December 1942. He was promoted to lieutenant on 25 May 1943 with seniority from 1 December 1942. HMS "Wren" was part of the 2nd Escort Group under the command of Captain Johnnie Walker, the most successful anti-submarine unit of World War II. He commanded a Motor Torpedo Boat from August 1944 to the end of the war.