Hong Kong Regulations

MERCHANT SHIPPING (PREVENTION OF OIL POLLUTION) REGULATIONS - REGULATION 19

Protective location of segregated ballast spaces

(1) In every new crude oil tanker of 20000 tons deadweight and above and every
new product carrier of 30000 tons deadweight and above, the segregated ballast
tanks required to provide the capacity to comply with regulation 18 which are
located within the cargo tank length shall be arranged, in accordance with the
requirements of paragraphs (2), (3) and

(4) of this regulation, to provide a measure of protection against oil outflow
in the event of grounding or collision.

(2) Segregated ballast tanks and spaces other than oil tanks within the cargo
tank length (Lt) shall be so arranged as to comply with the following
requirement-

ΣPAc + ΣPAs ≧ J[Lt (B + 2D)]

where- PAc = the side shell area in square metres for each segregated ballast
tank or space other than an oil tank based on projected moulded dimensions;
PAs = the bottom shell area in square metres for each such tank or space based
on projected moulded dimensions; Lt = the length in metres between the forward
and after extremities of the cargo tanks; B = the maximum breadth of the ship
in metres as defined in regulation 1(2); D = the moulded depth in metres
measured vertically from the top of the keel to the top of the freeboard deck
beam at the side at amidships. In ships having rounded gunwales, the moulded
depth shall be measured to the point of intersection of the moulded lines of
the deck and side shell plating, the lines extending as though the gunwale
were of angular design; J = 0.45 for oil tankers of 20000 tons deadweight and
0.30 for oil tankers of 200000 tons deadweight and above, subject to the
provisions of paragraph (3) of this regulation. For intermediate values of
deadweight the value of "J" shall be determined by linear interpolation. For
the purposes of this regulation the symbols referred to in this paragraph
shall have the meaning as laid down in this paragraph.

(3) For tankers of 200000 tons deadweight and above the value of "J" may be
reduced as follows-
Oc+Os J reduced = [J - (a - ____________________ )] or 0.2 whichever is
greater
4OA where- a = 0.25 for oil tankers of 200000 tons deadweight, a = 0.40 for
oil tankers of 300000 tons deadweight, a = 0.50 for oil tankers of 420000 tons
deadweight and above. For intermediate values of deadweight the value of "a"
shall be determined by linear interpolation. Oc = has the same meaning as in
regulation 27(1)(b)(i), Os = has the same meaning as in regulation
27(1)(b)(ii), OA = the allowable oil outflow as required by regulation 28(2).

(4) In calculating the value of "PAc" and "PAs" for segregated ballast tanks
and spaces other than oil tanks-

   (a)  where the width of any wing tank or space which extends for the full
        depth of the ship's side or from the deck to the top of the double
        bottom is less than 2 metres measured inboard from the ship's side at
        right angles to the centre line, that wing tank or space shall not be
        taken into account when calculating the protecting area "PAc"; and

   (b)  where the depth of any double bottom tank or space is less than B/15
        or 2 metres, that double bottom tank or space shall not be taken into
        account when calculating the protecting area "PAs". The width and
        depth of wing tanks and double bottom tanks shall be measured clear of
        the bilge area and, in the case of width, shall be measured clear of
        any rounded gunwale area.