the ballast water introduced into a tank which is completely separated from the cargo oil and oil fuel system and which is permanently allocated to the carriage of ballast or to the carriage of ballast or cargoes other than oil or noxious substances as variously defined in the Annexes of the present Convention, ballast - vajaliku püstivuse ja trimmi saavutamiseks alatiselt või ajutiselt laevale paigutatav last. B. võib olla vedel (b-vesi) või tahke (känkmalm, kivid, liiv jm.).