What is involved in "main engine overhauling"?

Main engine overhauling is a comprehensive maintenance procedure aimed at restoring the engine's performance to its optimal condition. This process typically involves disassembling the engine, inspecting its components for wear and damage, and replacing or refurbishing parts as necessary. During an overhaul, technicians will check critical elements such as the crankshaft, pistons, cylinders, and bearings. The objective is to enhance reliability and extend the engine's service life while improving efficiency and reducing the likelihood of future failures. This multi-faceted approach ensures that the engine can operate at peak performance levels for an extended period, making it an essential part of vessel maintenance.

The other options refer to less extensive or entirely different activities. A minor tune-up would involve simple adjustments or replacements of components without the in-depth analysis and refurbishment found in an overhaul. Replacing the engine entirely is a more drastic and costly solution, typically reserved for situations where the engine is irreparable. A temporary repair is focused on quick fixes to allow continued operation but does not involve the thorough inspection and servicing associated with an overhaul.