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The Heartbeat of Your Engine: Unleashing Power with the Main Engine Crankshaft

Updated: Apr 12, 2023

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The crankshaft is an essential component of a marine engine, and it plays a vital role in converting the reciprocating motion of the pistons into the rotational motion that drives the propeller. In simple terms, the crankshaft is like the backbone of the engine.

The crankshaft is a large and sturdy shaft that runs the length of the engine. It comprises several journals or bearing surfaces, precisely machined to support and rotate the connecting rods attached to the pistons. The number of journals depends on the number of cylinders in the engine, and each journal rotates in a set of bearings fitted into the engine block.

Main Engine Crankshaft installation
Newbuilding - ME bedplate & Crankshaft disassembled condition before landing the framebox - container vessel (Copyright ©, 2023)

The connecting rods are attached to the crankshaft using bearing shells, allowing them to rotate freely around it. As the piston moves up and down, it pushes and pulls the connecting rod, which turns the crankshaft. This rotation is transmitted to the propeller through gears and shafts, allowing the engine to drive the ship forward.

The crankshaft is subject to tremendous forces and stresses and must be made from high-strength materials such as forged steel or high-grade alloy. It is also designed with special features such as counterweights, which help to balance the forces generated by the reciprocating motion of the pistons.

Crankshaft of Diesel generator
Drydock - Crankshaft of Diesel generator (Copyright © Prohull Asia 2023)

Overall, the crankshaft is an essential component of a marine engine, and its design and construction are critical to the performance and reliability of the engine.

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