Thus, tier III standards will apply to a marine diesel
engine that is installed on a ship constructed on
or after 1 January 2016 and which operates in the
North American ECA or the United States Caribbean
Sea ECA that are designated for the control of
NOx emissions. In addition, the tier III standards
would apply to installed marine diesel engines when
operated in other ECAs which might be designated
in the future for tier III NOx control. They would apply
to ships constructed on or after the date of adoption
by the MEPC of such an emission control area, or
a later date as may be specified in the amendment
designating the NOx tier III ECA.49 Furthermore, the
tier III requirements do not apply to a marine diesel
engine installed on a ship constructed prior to 1
January 2021 of less than 500 GT, of 24 metres or
over in length, which has been specifically designed
and is used solely for recreational purposes. These
amendments are expected to enter into force on 1
September 2015.