A propeller shaft is a device on which a propeller is attached, transferring the power from the engine to the propeller. The propeller shaft runs from the transmission through a seal in an inboard engine application. It then runs through the hull and into the cutlass bearing just ahead of the propeller. The propeller shaft must run true and straight, free of any bends or it will vibrate the vessel as well as pre-maturely wear out the bearings and seals.

The propeller shaft incorporates a spline or taper on the end of the shaft where the propeller mounts. This allows the propeller to be mounted onto the propeller shaft without slipping or spinning free. Along with the spline, a threaded section of the shaft incorporates a nut and washer to tighten and secure the propeller to the shaft. A cotter pin is placed through a hole drilled through the shaft, and then bent over to prevent the nut from loosening or backing off.

In many outboard systems, a shear pin is used to prevent an object from coming in contact with the propeller and breaking the propeller shaft. A shear pin is a small metal bolt-like pin which is made of softer metal than the propeller shaft. When the propeller comes in contact with a hard object much like a rock or large underwater stone, the pin will shear off. This allows the shaft to continue rotating while the propeller stays still.

Allied Titanium manufactures all kinds of propeller shafts, so feel free to give us a call with your specific needs.