His first idea was to produce the propulsion force by using a belt running round two cylinders. Later Flettner decided that the cylinders would be better rotated by individual motors. Flettner applied for a German patent for the rotor ship on 16 September 1922.
Assisted by Albert Betz, Jacob Ackeret and Ludwig Prandtl, Flettner constructed an experimental rotor vessel, and in October 1924 the Germaniawerft finished construction of a large two-rotor ship named Buckau. The vessel was a refitted schooner which carried two cylinders (or rotors) about 15 metres high and 3 metres in diameter, driven by an electric propulsion system of power.
The rotor system was less efficient than conventional engines. Flettner turned his attention to other projects and the rotors were dismantled. Baden Baden was destroyed in a Caribbean storm in 1931.
The University of Flensburg is developing the Flensburg catamaran or Uni-cat Flensburg, a rotor-driven catamaran.
The German wind-turbine manufacturer Enercon launched and christened its new rotor-ship E-Ship 1 on the 2nd of August 2008. The ship will be used to transport turbines and other equipment to locations around the world.
Stephen H. Salter and John Latham recently proposed the building of 1500 robotic rotor-ships to mitigate global warming. The ships would spray seawater into the air which some believe may increase global dimming.