At 09.30 hours on 1 December 1939 the unescorted and neutral Arcturus (Master Nicolai Ludvik Engene) was hit on the port side underneath the fore mast by one G7e torpedo from U-31 and sank by the bow within three minutes about 80 miles east of Rattray Head. The master and eight crew members were lost. The U-boat had spotted the ship with lights set in a rain shower at 05.50 hours, but did not see the national markings, probably due to the low visibility from the periscope and missed with a first torpedo at 09.27 hours. Both lifeboats went down with the ship and the eight survivors rescued themselves on two rafts that floated free after she sank. They tied the rafts together and were spotted the next morning by a British aircraft which directed the Danish steam merchant Ivar to their location. The survivors were picked up and landed at Fredrikshavn, Denmark.