Ships will stay at standstill in the absence of its prime mover. It becomes derelict even with complete machines including propulsion systems. Without a ship's prime mover, it’s just a gargantuan log floating in the ocean at the mercy of winds, waves and tides because the prime mover is where the shaft and propeller are connected to complete the propulsion system. There are types of prime movers that are presently used.
We will try to discuss parts and construction, models, operation, maintenance and available troubleshooting procedures for each type of ship’s prime mover.
This type of prime mover employed in the main propulsion system is described as the pure internal combustion engine. It can tolerate low-grade fuel, and ignites the fuel directly inside the cylinder without the assistance coming from the outside. This happens when the piston goes up and compresses the air (oxygen) within the cylinder and high temperature is attained when exactly a finely atomized fuel is injected inside and mixes with the high temperature air causing an ignition (explosion inside) thus power is created and produces work.
There are two major kinds of diesel engine based on how they operate.
Four-stroke diesel engine
Let us examine how these four strokes (series of events) of the piston play to fill up the two revolutions of the crankshaft (one cycle) which produces power.
The image above illustrates the series of events how the four-stroke diesel produces power.
The marine diesel prime mover. - The four stroke plant
The video below shows how a Four-stroke cycle diesel engine works just click the video link.
How Diesel Engines Work - Part - 1 (Four Stroke Combustion Cycle)