Voith Schneider Propeller
The Voith Schneider Propeller is a specialized marine propulsion system. It is highly maneuverable; being able to change the direction of its thrust almost instantaneously. There is a large circular plate that is mounted on the bottom of the vessel. That plate has a number of long blades that protude from it. The circular plate rotates, acting to steer the vessel. Each of the blades that protude from it are designed to rotate independently.
The system changes the orientation of the paddles, in sync with the rotation of the plate, so that the plate rotation can provide thrust in any direction. Unlike a Z drive, changing the direction of thrust merely requires changing the pattern by which the vertical blades change their orientation.
This propulsion system is like a cross between an egg-beater and wankel engine.