In June 1957, after spending over 12 years resting on the Baltic Sea floor, U-2540 was recovered and refurbished at Howaldtswerke in Kiel. It was then commissioned as a research vessel by the Bundesmarine, serving as a test boat (Class 241) from September 1, 1960, to August 28, 1968. Upon its relaunch, the submarine was renamed Wilhelm Bauer in honor of the designer of the first German U-boat, the Brandtaucher, which was built in Kiel by August Howaldt in 1850. The ex-Type XXI Wilhelm Bauer originally designated as U-2540 rebuilt in service with the Bundesmarine in the 1960s.