At night as the liners were illuminated by the moon, Wanklyn attacked with four torpedoes. The submarine could only manage 10.5 knots and a swell was rocking her from side to side, making aiming difficult. It was too dark to begin a submerged attack against a fast-moving convoy. Wanklyn deduced that the attack must be made at long range, outside the escorts' protective screen. Wanklyn saw that on occasion the targets overlapped, and as they did so he fired at the bow of one and stern of the other. Bringing back the aiming point to the centre of the overlapping mass, he fired two more torpedoes. Two torpedoes struck. The first destroyed the propellers of the "Oceania" and she stopped dead in the water. The other struck and tore a large hole in "Neptunia". The escorts stopped to pick up survivors. Wanklyn retired to a safe distance and reloaded. Closing to finish the crippled "Oceania", Wanklyn was forced to crash-dive because of an Italian destroyer. Too close to fire, he continued under the liner and emerged on the other side. There he fired a single torpedo which blew the ship apart and it sank. "Unbeaten" had arrived and was about to fire but saw the second strike disintegrate the ship, which was carrying several thousand German soldiers. "Neptunia" limped off with a destroyer at but her bulkheads collapsed due to the damage and she came to a stop with a single destroyer in attendance. Two more torpedoes from "Upholder" sank her. Wanklyn had accounted for nearly 40,000 tons in the same attack. The gyro-compass had been put out of action during the action.