On 17 Feb 1945, HMS Bluebell (K 80) (Lt G.H. Walker, DSC, RNVR) was searching for U-boats off Kola Inlet ahead of convoy RA-64, which set out on this day. At 17.30 hours, she was struck in the stern by a Gnat from U-711 just after increasing speed after she apparently detected the U-boat about 30 miles east-northeast of Kildin Island. The corvette blew up as the hit detonated her depth charges and sank in less than 30 seconds. HMS Zest (R 02) (LtCdr R.B.N. Hicks, DSO, RN) arrived at the sinking position in about 10 minutes and her lookouts heard cries from about a dozen men swimming in the ice cold water, but could not stop due to the danger of being herself torpedoed. The destroyer commenced a search for the attacker until being relieved by HMS Opportune (G 80) (Cdr R.E.D. Ryder, VC, RN) and lowered a whaler at 17.53 hours. However, only one of three unconscious survivors recovered could be revived.