Propeller Shaft

A rotating shaft that transmits torque from an engine or gearbox to a propeller.

In a conventional shaft installation it passes through the hull via a stern tube and seal or stuffing box, is supported by bearings, and connects to the gearbox through a coupling. The propeller is secured at the outer end, commonly on a taper with a key or keyless fitting.

Correct alignment, bearing support, sealing and corrosion protection are necessary to limit vibration, wear and water ingress. A bent shaft, worn cutless bearing, damaged coupling or fouled propeller can create symptoms elsewhere in the drivetrain.