AB / Motorman (Матрос-моторист) / Motorman (Моторист) / OS (Вахтенный матрос) / Seamen (Матрос)

AB Seaman, OS

Officer in charge of an engineering watch in a manned engine-room or as designated duty engineer in a periodically unmanned engine-room on ships powered by main propulsion machinery of 750 kW propulsion power or more, Motorman

Officer in charge of a navigational watch on ships of 500 gross tonnage or more, Officer in charge of a navigational watch on ships of less than 500 gross tonnage, engaged on near-coastal voyages, OS

OS, AB Seaman