At 00.36 hours on 17 May 1941 the unescorted Marisa (Master J.C. Landman) was hit in the engine room by one torpedo from U-107, killing the fourth engineer and one crew member. The U-boat had followed the tanker since 12.49 hours the day before. The tanker stopped and was hit in the stern by a coup de grâce at 01.15 hours, after the crew abandoned ship in three lifeboats. 15 minutes later the U-boat surfaced, opened fire with the deck gun and hit the ship with 20 rounds, but the next grenade burst in the barrel and made the deck gun useless. The burning tanker settled by the stern, but the bow remained afloat. At 02.17 hours, the 20mm AA gun was used to open holes in the empty tanks until the weapon was damaged too by a round that exploded in the barrel. A part of the barrel hit a man standing on the conning tower, but fell off without wounding him. Hessler wrote in the KTB: What kind of weapons and munitions do we have, we must be afraid of them.

On 20 May, one lifeboat was found by HMS Columbine (K 94) (T/Lt S.J. Lavis, RNR) and a second by the British patrol yacht HMS Surprise. The third lifeboat with the master landed at the coast of French-Guinea on 23 May.