According to the installation type:

Inboard engine: The engine is installed on the inner side of the hull and used by large yachts.

Inboard and outboard engine: The engine is installed on the inside of the hull, and the propeller is installed on the outside of the hull. For small and medium boats.

Outboard motor: a machine that is not permanently fixed on the ship and needs to be disassembled and moved to shore for propulsion at any time. Because of its small size, high power and high speed, it is widely used in high-speed boats, fishing boats and work boats.

Jet engine: Inhale water into the engine, accelerate the jet to the rear to obtain power, no rudder is needed, just change the direction of the jet to change the direction of the ship.

According to the fuel used:

Gasoline engine: Compared with diesel engine, it is smaller in size, lighter in weight, low in noise and easy to repair. It is relatively easy to start because gasoline has a low ignition point and low thermal efficiency. The thermal efficiency is converted into kinetic energy and the journey is short. The conversion of kinetic energy into speed is easy to play, quick to accelerate and easy to control. It is suitable for propelling hulls and small boats with lighter loads.

Diesel engines: Compared with gasoline engines, the advantages of diesel engines are that diesel is cheap, economical, and has fewer failures. From the horsepower point of view, diesel engines have more horsepower than gasoline engines and are more widely used on ships. The service life of the diesel engine is relatively long and the operating cost is relatively small. Diesel has high hot spots, high thermal efficiency, long travel time for thermal efficiency to be converted into kinetic energy, slow kinetic energy development and acceleration response, but strong kinetic energy conversion and increased torque capabilities, which are more suitable for driving heavy hulls and ships with heavier loads.