At 20.21 hours on 18 Oct 1940 the Shekatika (Master Robert Paterson), a romper from convoy SC-7, was hit amidships by one torpedo from U-123 about 90 miles east-southeast of Rockall and seven minutes later by a coup de grâce under the bridge, but both hits did not have much effect. When the U-boat surfaced at 20.30 hours, U-99 (Kretschmer) made the same about 300 metres away and Kretschmer was a bit angry because he had chased the same ship but planned his attack a few minutes too late. After the crew had abandoned ship on rafts, U-123 fired a second coup de grâce into the vessel at 20.46 hours and then left the slowly sinking ship.

At 23.17 hours, U-100 (Schepke) fired a coup de grâce into the abandoned Shekatika, but she remained afloat until U-123 found her again at 02.44 hours on 19 October. At 03.17 hours, a fifth torpedo hit the ship amidships, starting a fire in the engine room. The vessel developed a list and the deck cargo of pit props fell overboard before she sank. The master and 35 crew members were picked up by HMS Fowey (L 15) (Lt C.G. de L. Bush, RN) and landed at Grennock on 20 October.