PURPOSE: To plan to save labor for maintenance and service works and improve working circumstance by providing an exclusive maintenance room for the maintenance and service for a middle-speed diesel engine utilized as a main diesel engine for a ship.

CONSTITUTION: An engine traveling hoist between a main engine and an exclusive maintenance room and a maintenance traveling hoist in the exclusive maintenance room are provided respectively, and machine and equipments necessary for maintenance and service are arranged in the exclusive maintenance room. Parts removed from the main engine are carried by the engine traveling hoist into the exclusive maintenance room directly, and the service works for these parts may be carried out in a place reasonably arranged by the machines and equipments for maintenance works and having a good working circumstance.