Auxiliary

A secondary engine or motor on a vessel, typically used for manoeuvring or as a backup to the primary propulsion system. 

An auxiliary refers to a secondary power source, often an internal combustion engine or an electric motor, that is used in addition to the vessel’s primary means of propulsion, such as sails. For sailing yachts, the auxiliary engine is crucial when wind conditions are unfavourable or when precise manoeuvring is required, such as docking or navigating narrow channels. The auxiliary engine can also serve as a backup in case of an emergency, providing propulsion when the primary system fails. These engines are typically smaller than the main engine and are often mounted either inboard or outboard, depending on the size and type of the vessel. In larger vessels, auxiliary systems may also refer to additional machinery that supports other functions, such as generators for electrical power, pumps, or even thrusters for enhanced control. The term “auxiliary” underscores the supportive role of these systems, which are not the primary means of propulsion but are nonetheless essential for the safe and efficient operation of the vessel.