The crews on U.S. Navy ships and Coast Guard cutters are generally divided into three departments. The Engineering Department is responsible for all the engines, motors, pumps, compressors, refrigerators, evaporators, all piping systems (fuel, water, compressed air, sewage, etc). Engine room ratings include: Machinist Mate; Engineman; Electricians Mate; & Damage Controlman. The Deck Department is responsible for the general maintenance and upkeep of the hull, cargo equipment, small boats, weapons systems, anchors, etc. Deck ratings include: Boatswains Mate; Gunners Mate; Master at Arms; etc. The Operations Department (O Section) is responsible for navigation, communications, signal flags and semaphore lights. Ratings in the Operations include: Quartermaster; Signalman; Radioman; Radarman; Cooks; Yeoman; etc. Ships with flight decks will have an Aviation Department or Aviation Detachment; depending on the size of the ship.