<![CDATA[AHTS (Anchor Handling Tug Supply) vessel is specifically vessel that designed to support activities, offshore drilling work for oil and natural gas from preparation, supply of cargo to production [1]. As a support vessel for offshore operations in carrying out its functions, this ship is of course equipped with a main engine. The main engine on board is the main propulsion engine so that the ship can run, maneuver and move anywhere to carry out its operations [2], so the performance of the main engine on board is very important. There are various types, maker and brands of main engines commonly used on AHTS vessel. In general, AHTS ships are equipped with 2 main engines, many ships use 1 main engine, and for crew boat types to support offshore operations, some are equipped with 4 main engines. But it is very rare to find a ship that uses 3 main engines. This study aims to analyze the performance of three main engines of the AHTS vessel Christos LVII. This research is a survey research combined with library research by examining several sources and direct observation and analysis [3]. The results showed that: exhaust gas temperature, lubricant pressure and temperature, coolant temperature, gearbox oil pressure, air pneumatic and air starting pressure also fuel pressure during 1 month is always in normal condition and no deviations ever occurred. The performance of the main engine which is 4 years old is still good and normal according to standard parameters during the vessel's first sea trial. The function of the main engine on the vessel AHTS LVII is very important because apart from being the prime mover of the ship's propeller shaft, the main engine is also used to drive the shaft generator which produces electric current to be used to run all of equipment on board.]]>
