Ship Propulsion Equipment
 
A ship must be equipped with a complete set of power plants and auxiliary equipment that meet the specifications before it can sail on the water. These power plants include the ship's main propulsion plant, auxiliary power plant, steam boiler, refrigeration and air conditioning plant, compressed air plant, ship pumps and piping system, water making plant, and automation system, etc. These electromechanical power equipment are mainly concentrated in the engine room, and the technical department specifically managing these equipment is the engine room department.
 
Main Propulsion Plant
 
The ship's main propulsion plant, also known as the "main engine," is the heart of the ship and the most important part of the ship's power equipment. It mainly includes:
 
The ship's main engine, a colloquial term for an engine that generates the ship's propulsion power, includes various pumps and heat exchangers, piping systems, etc., that serve the main engine. Currently, the main engines of merchant ships are mainly ship diesel engines, followed by steam turbines.
 
Transmission system, the equipment that transmits the power of the main engine to the propeller. In addition to transmitting power, it can also reduce speed and vibration. Small ships can also use the transmission equipment to change the rotation direction of the propeller. The transmission equipment varies slightly depending on the type of main engine. In general, it consists of a reducer, clutch, coupler, coupling, thrust bearing, and ship shaft, etc.
 
Shaft system and propeller. Among ship propellers, propellers are the most widely used, mostly using fixed-pitch or controllable-pitch propeller propellers; the ship shaft system is a device that transmits the power generated by the main engine to the propeller. The ship's main engine drives the propeller to rotate and generate thrust through the transmission system and shaft system, overcoming the hull resistance to make the ship move forward or backward.
 
Auxiliary power plant. The ship's auxiliary power plant, also known as the "auxiliary engine," refers to the ship's generator, which provides electricity for the ship under normal and emergency conditions. The ship's power station is composed of engine sets, switchboards, and other electromechanical equipment.
 
Generator sets. The original power is mainly provided by diesel engines. Considering the safety, reliability, and ease of maintenance of the ship, large ships are equipped with no less than two diesel generators of the same model, and multiple units can generate electricity simultaneously as needed.
 
For energy saving, some ships can use the main engine's drive shaft to drive the generator to generate electricity (shaft-driven generator) or use the waste heat from the main exhaust gas to generate low-pressure steam to drive the steam turbine generator set to generate electricity, etc., during navigation.
 
Switchboard. It distributes, controls, transmits, transforms, and converts electricity to meet the needs of various electric drive equipment and the entire ship's living, lighting, signaling, and communication.