Large propellers provide a high degree of bite and control at low speeds but high drag when sailing. Small propellers have less drag but also…

To keep the shaft aligned, and provide support, it is held by two sets of bearings – one supporting the gearbox, fixed inside the boat,…

Conventional seals consist of a stuffing box into which are laid several layers of grease-impregnated packing specifically made for the purpose. The box is closed…

Unless it is specifically designed to allow an angular misalignment, you must take the same care lining up a flexible coupling and its engine. This…

Whether the engine is mated to its drive shaft by a flexible coupling or connected directly to the propeller shaft flange, it must be carefully…

The alternator constantly senses the output voltage and when a preset voltage is reached – usually 14.2 volts – will progressively shut itself down to…

These generate electric power and are driven by the engine, usually through a V-belt or multi V-belt. The alternator normally runs faster than the engine,…

The starting system comprises two components, the motor itself and its solenoid-operated electrical relay. The relay is necessary because the heavy electrical currents delivered to…

Engine lubricating oils are designed to be mixable with oils of a different standard. Engines cover a wide range of service conditions from low powered,…

1. Run the engine up to operating temperature and stop. 2. Drain the engine oil through the sump plug into a container, or pump oil…