In June 1957, after more than 12 years on the floor of the Baltic Sea , U-2540 was raised and overhauled at Howaldtswerke , Kiel . The submarine was commissioned as a research vessel in the Bundesmarine , serving from 1 September 1960 until 28 August 1968 as a test boat (class 241). On relaunch she was renamed Wilhelm Bauer , after the designer of the first German U-boat, Brandtaucher , built in Kiel by August Howaldt in 1850. From May 1970 she again entered service, this time with a civilian crew and served as a testbed for the technical innovations of the class 206 U-boat . After an underwater collision with the German destroyer Z-3 (D172) on 6 May 1980 Wilhelm Bauer was discharged from use at Eckernförde on 18 November 1980 and finally released from service on 15 March 1982.