 "U-103" was laid down on 6 September 1939 at DeSchiMAG AG Weser in Bremen as yard number 966.She was launched on 12 April 1940 and commissioned on 5 July under the command of "Korvettenkapitän" Victor Schütze.After her warm-up, (designed to give her an opportunity to train and repair minor faults), she was deployed into the North Atlantic in September 1940 and saw overwhelming success, sinking 45 ships and damaging three other vessels.