At 17.55 hours on 22 Sep 1940 the Union Jack (Skipper Viggo Dam) was stopped with machine-gun fire by U-31 about 100 miles northwest by north of Butt of Lewis, Hebrides. The crew immediately abandoned ship in a small rowboat. Only a few rounds of the about 25 rounds fired from the deck gun hit the vessel, but she sank by the bow after 10 minutes. The Germans did not question the crew and just left the area. The survivors had no food or water in the rowboat but nevertheless managed to reach the Flannan Isles after 36 hours. From there they were taken by HMS Grosmont Castle (FY 671) to Stornoway, arriving on 25 September.