Rotor ship

A rotor ship is a type of ship designed to use the Magnus effect for propulsion. The ship is propelled, at least in part, by large powered vertical rotors, sometimes known as rotor sails. German engineer Anton Flettner was the first to build a ship that attempted to tap this force for propulsion, and ships using his type of rotor are sometimes known as Flettner ships.

The Magnus effect is a force acting on a spinning body in a moving airstream, which produces a force perpendicular to both the direction of the airstream and the axis of the rotor.