How do ships use bunker fuel for power?

burnt to raise steam in boilers. The resulting steam is applied to a turbine. The power output of the turbine is geared down and applied to the screws which propel the ship. Diesel engines can also burn bunker oil. The oil is heated to made it more fluid.

These engines are often slow running and the drive is applied directly to a single screw.

When starting and manoeuvring a lighter grade of oil is used.