At 18.05 hours on 12 October 1939 U-37 tried to stop the unescorted and neutral Aris about 150 miles west of Achill Head, but she did not stop and used the radio because they had transported war materials to Britain according to the master. The crew abandoned ship in two lifeboats after a round hit the funnel at 18.20 hours. At 19.45 hours, the U-boat fired one G7a torpedo which passed underneath the keel. She was sunk by a second torpedo after shells fired into the waterline did not sink the ship. The U-boat then towed the lifeboats 80 miles towards the coast of Ireland before leaving the area. The survivors were picked up by the Danish motor merchant Sicilien and landed at Stornoway.