On 17 April 1943, HMS P-615 (Lt C.W.St.C. Lambert, DSC and Bar, RN) left Freetown under escort by the British minesweeper HMS MMS-107 (J 607) (Skipper H.J. Craven, RNR) on passage to the South Atlantic Command to provide A/S escort training. During the night they lost contact but found each other the next morning. U-123 spotted both vessels at 03.44 hours and missed them with two spreads of two torpedoes at 05.34 and 06.47 hours, one of the torpedo tracks was sighted by the escort, but was put down to a porpoise. At 11.01 hours, a merchant vessel was sighted and at 11.53 hours the U-boat fired one torpedo at the minesweeper on station about 300 yards off the submarine´s starboard quarter, but missed. At 11.54 hours, a spread of two torpedoes was fired at the submarine, which was hit by one of them on the starboard side, exploded and sank immediately about 100 miles southwest of Freetown. The commander, six officers and 37 ratings were lost.

At 12.39 hours, U-123 torpedoed the Empire Bruce and left the area after sinking her with two coups de grâce. The minesweeper picked up the survivors and returned to Freetown.