MEPC 71 agreed a compromise proposal on effective dates for the fitting of ballast water treatment systems on existing ships. Ships constructed before 8 September this year will be required to fit a system by the date of their IOPP renewal surveyin accordance with a schedule set out in an amendment to the convention. Ships must comply by the date of their next renewal survey if that falls after 8 September 2019 or if their last survey was carried out between 8 September 2014 and 8 September 2017. Where the next survey is due before 8 September 2019, they will not be required to comply until the following survey, providing they did not “decouple” their IOPP survey by instigating it between 2014 and 2017. Until such time as ships have installed a treatment system, they must perform Ballast Water Exchange in accordance with the Convention, in other words at least 50 miles from the nearest land and in water of a depth of at least 200 metres. MEPC 71 issued a circular clarifying that where a vessel is on a short voyage and cannot meet these conditions without deviating, then it is not necesary to perform ballast water exchange. This circular, together with the revised guidelines on ballast water exchange, can be found in the Members’ Area.