Segregated Ballast Tank

A segregated ballast tank (SBT) is a tank dedicated to ballast water, with no piping connection to the cargo oil or fuel oil systems, so ballast never contacts oil. MARPOL Annex I Regulation 18 requires SBTs on crude oil tankers of 20,000 deadweight tonnes and above and product tankers of 30,000 deadweight tonnes and above, with the tanks arranged to also give protective location against collision and grounding outflow. SBTs eliminated the practice of carrying ballast in cargo tanks and the oily discharges that followed, a major source of operational oil pollution before the requirement. The arrangement supports the Annex I oil outflow standards.