1 Subject
to the provisions of paragraph 4 of regulation
3 of this Annex, oil tankers of 150 gross tonnage and above
shall be provided with slop tank arrangements in accordance with the
requirements of paragraphs 2.1 to 2.3 of this regulation. In oil tankers
delivered on or before 31 December 1979, as defined in regulation 1.28.1, any cargo
tank may be designated as a slop tank.
2.1 Adequate
means shall be provided for cleaning the cargo tanks and transferring
the dirty ballast residue and tank washings from the cargo tanks into
a slop tank approved by the Administration.
2.2 In
this system arrangements shall be provided to transfer the oily waste
into a slop tank or combination of slop tanks in such a way that any
effluent discharged into the sea will be such as to comply with the
provisions of regulation 34 of
this Annex.
2.3 The arrangements
of the slop tank or combination of slop tanks shall have a capacity
necessary to retain the slop generated by tank washings, oil residues
and dirty ballast residues. The total capacity of the slop tank or
tanks shall not be less than 3 per cent of the oil carrying capacity
of the ship, except that the Administration may accept:
-
.1 2% for such oil tankers where the tank washing
arrangement are such that once the slop tank or tanks are charged
with washing water, this water is sufficient for tank washing and,
where applicable, for providing the driving fluid for eductors, without
the introduction of additional water into the system;
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.2 2% where segregated ballast tanks or dedicated
clean ballast tanks are provided in accordance with regulation 18 of this Annex, or
where a cargo tank cleaning system using crude oil washing is fitted
in accordance with regulation 33 of
this Annex. This capacity may be further reduced to 1.5% for such
oil tankers where the tank washing arrangements are such that once
the slop tank or tanks are charged with washing water, this water
is sufficient for tank washing and, where applicable, for providing
the driving fluid for eductors, without the introduction of additional
water into the system; and
-
.3 1% for combination carriers where oil cargo
is only carried in tanks with smooth walls. This capacity may be further
reduced to 0.8% where the tank washing arrangements are such that
once the slop tank or tanks are charged with washing water, this water
is sufficient for tank washing and, where applicable, for providing
the driving fluid for eductors, without the introduction of additional
water into the system.
2.4 Slop
tanks shall be so designed particularly in respect of the position
of inlets, outlets, baffles or weirs where fitted, so as to avoid
excessive turbulence and entrainment of oil or emulsion with the water.
3 Oil tankers
of 70,000 tonnes deadweight and above delivered after 31 December
1979, as defined in regulation
1.28.2, shall be provided with at least two slop tanks.