Sumar was obtained by the British Admiralty, armed and commissioned as HMS Sumar in July 1942. Her first commanding officer, Temporary Lieutenant-Commander C. A. King, DSC, Royal Navy Reserve, was appointed on 12 July 1941. Armed for anti-submarine warfare, she was assigned to the Royal Naval Examination Service on the America and West Indies Station, based at the Royal Naval Dockyard, Bermuda. , a Bermudian tender which had been similarly commissioned, and which had been used by the Royal Naval Examination Service at Bermuda since the start of the war, was transferred to the Mediterranean, but sunk on transit on 16 October 1942 by the German submarine . Although the Examination Service was responsible for anti-submarine duties inside Bermuda's barrier reef, the ocean outside the reef was normally patrolled by . Evadne was also responsible for escorting merchant vessels to Bermuda where they formed into convoys to cross the Atlantic (convoys formed at Bermuda were coded BHX and merged at sea with convoys from Halifax, Nova Scotia, coded HX, as the relatively smaller circumference of a larger circle meant it took fewer escorts to defend one large convoy than two smaller).
