After 22.00 hours on 22 May 1940 the unescorted Dunster Grange was attacked by U-37 with four torpedoes south of Ireland. The first torpedo with magnetic fuze passed underneath the ship without detonating and the second torpedo detonated prematurely, alarming the crew of the ship which evaded the next two torpedoes. The U-boat then attacked with the deck gun and scored a hit with the first round, but accurate return fire forced the Germans to give up the attack and the Dunster Grange safely arrived at Liverpool on 24 May. Her radio messages alerted HMS Montrose (D 01) (Cdr C.R.L. Parry, RN), HMS Wakeful (H 88) (LtCdr R.L. Fisher, RN), HMS Vanquisher (D 54) (LtCdr C.B. Alers-Hankey, RN) and HMS Deptford (L 53) (LtCdr G.A. Thring, RN), which unsuccessfully searched the area for the attacker.