German merchant ship with 16,870 GRT built for the trial of nuclear marine propulsion. A pressurized water reactor with a thermal power of 38 MW was used for propulsion. First nuclear voyage on 11th Oct. 1968. By the end of 1978, the ship travelled 642,000 nautical miles and transported 776,000 t freight. The “Otto Hahn” was shut down in 1979 and the reactor system and all radioactive parts were disassembled and removed. The ship subsequently re-entered service following incorporation of conventional propulsion.