
The marine auxiliary engine is used to generate electricity onboard marine vessels, which is termed as an auxiliary unit. Initially, steam turbine propulsion was used, which was later replaced by diesel, LNG, nuclear, and other fuels. Nuclear propulsion is used for naval purposes for its fast movement, and the other type of fuel ships are used for the commercial purposes. The auxiliary unit is designed to support the main engine and to ensure the proper functioning of the ship. It is widely used in tankers, containers, and cargo carriers. The auxiliary unit includes the pumps, compressor, and blowers for the circulation of fuels and fresh and sea water in the cooling system. In addition, it has a separator to remove dirt from the fuel oil, which is referred as the heart of the ship. The marine auxiliary engine works on heavy fuel oil (HFO) or diesel.