Engine Room Ratings are in charge of maintaining shipboard machinery by performing routine oiling, greasing, and servicing, repairing, and fitting equipment parts, and assisting engineering Officers in monitoring the smooth and safe operation of the main plant (ship's engine) and other critical equipment.Ratings is a general term for all skilled seafarers who generally perform support work for Officers in all divisions. The job entails a wide variety of activities that are critical to the ship’s safe operation and upkeep. In the following paragraphs we will cover the duties carried by the various GP Ratings or ranks in different departments onboard ship.