In August 1939 the German Kriegsmarine request MS Preussen vor service as Minelayer. The Preussen rebuild to a Minelayer armed whit two 8,8cm SK L/45 and four 2-cm-Flak 30 equipt with about 400 Mines. He laid their first Barrage on 4. Sept 1939 south of the great Belt. Besides she acted as auxiliary Cruiser to Control the shipping in the Baltic Sea. Between 7 Oct 1939 and 15 Febr 1940 she conducted several sorties and captured Swedish, Finnish, Danish and Estonian vessels, suspected of carrying contraband, mainly cellulose, timber, ore and foodstuffs. From the 29. April 1940 she lay mines in the Skagerrak. on 30. April 1940 01:55 am she collided whit the escorting German torpedoboat Leopard. The Leopard sunk in the Morning Hours only one crewman died. When Germany attacked the Soviet Union on 22 June 1941 the Preussen also participated in minelaying in the Baltic Sea to prevent Soviet vessels of breaking out into the open Baltic. July 1941 the Preussen her sistership Hansestadt Danzig and Tannenberg send to lay the minefields Wartburg I-III. On 9 July 1941 she an the two other Ships ran into a Swedish minefield layed on Germanys request. The Swedish mines closed a gap east of the village of Gräsgard on the south tip of the island of Öland, to hinder Soviet vessels to pass close to the Swedish coast. The Swedish minesweeper Sandön, guarding the barrage, tried to warn the German ships but it was too late, all three auxiliary minelayers sustained mine hits at 6:40 pm and sank in shallow water, the last at 7:58 pm. Fortunately, fatalities were low, only 20 crew members died on all three vessels together. Preussen sank first, because her forward bulkhead of the auxiliary engine room was destroyed and she poured water, furthermore she was totally ablaze. The German Kriegsmarine know About the Swedisch Minefield but don´t informed the Preussen and the other two ships. The wreck was found in 1952 by the Swedish salvage company Intermarin in a depth of 21 meters in position 56.15.30N 16.43.30E and raised in 1953, and scrapped in the same year.

Preussen before conversion to a Minelayer:

MV Preussen: https://www.planetminecraft.com/project/mv-preussen/
MV Preussen (1934): www.planetminecraft.com/project/mv-preu-en-1934/