Voith Schneider Propeller

The Voith Schneider propeller (VSP), also known as a cycloidal drive is a specialized marine propulsion system (MPS). It is highly maneuverable, being able to change the direction of its thrust almost instantaneously. It is widely used on tugs and ferries.

Operation

From a circular plate, rotating around a vertical axis, a circular array of vertical blades (in the shape of hydrofoils) protrude out of the bottom of the ship. Each blade can rotate itself around a vertical axis. The internal gear changes the angle of attack of the blades in sync with the rotation of the plate, so that each blade can provide thrust in any direction, very similar to the collective and cyclic of helicopter flight controls.

Unlike the azimuth thruster (where a conventional propeller is rotated about the vertical axis to direct its thrust, allowing a vessel to steer without the use of a rudder), the Voith-Schneider drive merely requires changing the pattern of orientation of the vertical blades. In a marine situation, this provides for a drive which can be directed in any direction and thus does away with the need for a rudder. It is highly efficient and provides for an almost instantaneous change of direction. These drives are becoming increasingly common in work boats such as fireboats and tugboats where extreme manoeuvrability is needed.