The Chief Engineer, also known as the Chief Engineering Officer or Chief Engineer Officer (CEO), is the highest-ranking engineer on board a ship. They are responsible for overseeing the entire engineering department, which includes the operation, maintenance, and repair of the ship's machinery, propulsion systems, electrical systems, and other mechanical equipment. The Chief Engineer ensures that the ship's engineering systems are running efficiently, monitors fuel consumption, manages engineering crew, and coordinates with other departments for smooth operations. They typically hold the highest level of engineering qualification and have extensive experience in marine engineering.