Osdorf was a German fishing trawler that was built in 1921 as Rendsburg. Renamed in 1939, she was requisitioned by the Kriegsmarine in the Second World War for use as a Vorpostenboot, serving as V 311 Osdorf. Restored to her ownes post-war, she was sold to Norway in 1951 and converted to a cargo ship, renamed Vestland. She was renamed Sirabuen in 1952, serving until 1956 when she was lost in a collision.