Between 23.50 and 23.56 hours on 25 Aug 1940, U-124 fired four single torpedoes at four ships in convoy HX-65A 23 miles north of Butt of Lewis, Hebrides and claimed the sinking of all four. However, only three ships were hit: Harpalyce and Fircrest were sunk and the Stakesby was badly damaged.

The Harpalyce (Master William John Rees) was the ship of convoy commodore (Vice-Admiral B.G. Washington, CMG, DSO, RNR (Rtd)) in station #31 and sank by the stern with a list to port within one minute after being hit by one torpedo, leaving the crew no time to launch the lifeboats. The master, the commodore, four naval staff members, 34 crew members and two gunners (the ship was armed with one 4in gun) were lost. Five crew members clung to debris or swam to rafts that floated free, neither the designated rescue ship nor the escorts picked them up, but the British armed trawler HMS Fort Dee located them when investigating the burning Stakesby nearby and picked them up at 03.45 hours on 26 August. The trawler searched the area for further survivors during daylight and then landed the survivors at Kirkwall, Orkneys.