At 23.27 hours on 18 Feb 1942 the Somme (Master Clarence Cornish Prosser), dispersed on 15 February from convoy ON-62, was hit amidships by one torpedo from U-108 southeast of Sable Island. The ship settled by the stern, while the crew abandoned ship in three lifeboats. At 23.38 hours, the U-boat fired a coup de grâce, which hit aft and caused the ship to sink fast by the stern. The survivors in the lifeboats were questioned by the Germans, but they were never found. The master, 47 crew members and ten gunners were lost.

At 00.45 hours on 19 February, U-108 fired with the 20mm AA gun at a motor launch that had been part of the deck cargo and floated free when the ship sank. The launch was left in a sinking condition, but three hours later the U-boat fired its last torpedo at the shadow of a flat vessel without a bridge in a rain squall and heard several detonations after eight minutes. Scholtz thought that he damaged a patrol craft, but it is very likely that the target had been the motor launch from the Somme.