In 1937 Schiffbau-Gesellschaft "Unterweser" in Wesermünde, Bremerhaven, built a trawler for the fishing fleet of Hans Kunkel.

[2] Deutsche Schiff- und Maschinenbau (DeSchiMAG) built her engines in its Seebeck works at Wesermünde.

It was supplemented by an exhaust steam turbine, which drove the same propeller shaft via DeSchiMAG's patent Bauer-Wach system of a Föttinger fluid coupling and double-reduction gearing.

The combined power of her reciprocating engine plus exhaust turbine was rated at 96 NHP,[2] and gave her a speed of 10 knots (19 km/h).

Her port letter and number were PG 512,[4] and her wireless telegraph call sign was DFCY.

M-1903 helped to rescue the cruiser Lützow, which was damaged on 9 April in the Battle of Drøbak Sound.

On 15 October, an Allied force of 21 Beaufighters and 17 Mosquitoes from Banff and Dallachy Wings attacked the tanker and her escort.