rotor ship

A rotor ship, or Flettner ship, is a type of ship designed to use the Magnus effect for propulsion. The Magnus effect is a force acting on a spinning body in a moving airstream, which acts perpendicularly to the direction of the airstream. Rotor ships typically use rotor sails powered by a motor to take advantage of the effect. German engineer Anton Flettner was the first to build a ship which attempted to tap this force for propulsion.