On 9 September 1940 USS Crowninshield (DD 134) was decommissioned at Halifax, Nova Scotia, and delivered to British authorities in the land bases for destroyers exchange. She was commissioned in the Royal Navy as HMS Chelsea the same day. Chelsea reached Devonport, England, 28 September 1940. Assigned to the Sixth Escort Group, Western Approaches Command, Liverpool, for Atlantic convoy duty, she fought the double-menace submarine and air attacks on vital supplies. On 6 April 1941 she rescued 29 survivors of SS Olga S. which had been sunk by an air attack Chelsea joined Arbutus 5 February 1942 to hunt for a submarine sighted from their convoy. Two hours later Arbutus was torpedoed. Chelsea opened fire on the surfaced submarine and made three depth charge attacks after she dived but contact was lost and she returned to pick up the survivors from Arbutus. In November 1942 Chelsea was lent to the Royal Canadian Navy and until the end of 1943 operated in the mid and western Atlantic Ocean escorting convoys to and from Great Britain. She returned to Londonderry, Northern Ireland, 26 December 1943 and early in 1944 was reduced to reserve in the Tyne. On 16 July 1944 she was transferred to Russia and renamed Derskni.