Officer in charge of a navigational watch on ships of 500 gross tonnage or more (Вахтенный помощник капитана морского судна валовой вместимостью 500 и более) / OS (Вахтенный матрос)

OS

Chief Officer, Master on ships of less than 500 gross tonnage engaged on near-coastal voyages, 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