O-class battle cruiser is the World War II Germany "Z plan" contains to replace the Deutschland class battle cruiser. The main gun is the same with the Bismarck 380mm double turret 3. O-class power system is quite characteristic, the use of three-axis propulsion, the steam turbine is responsible for driving the two sides of the two axes, the central axis by the MAN diesel engine to meet the requirements of life and speed, speed up to 33.5. The ship was designed to be used as the Atlantic high-speed broken ship, its plan in 1939 in Kiel and Wilhelm's three shipyards at the same time started, but the construction plan was canceled by the end of the year.