Voith-Schneider Propeller

Cycloidal propulsion unit consisting of a vertical disc carrying four to six vertical blades around its rim, each blade pivoting under cam control as the disc rotates. Varying the pivot pattern (the cycloidal pitch) directs thrust in any horizontal direction without changing rotation speed. Voith-Schneider drive (Voith Marine Technology) is fitted to tractor tugs, ferries, and offshore vessels where instantaneous omnidirectional thrust is more valuable than top-end open-water efficiency. The drive is mechanically complex but mature, with maintenance intervals and class survey requirements published by the manufacturer.