Hong Kong Regulations

MERCHANT SHIPPING (PREVENTION OF OIL POLLUTION) REGULATIONS - REGULATION 28

Limitation of size and arrangement of cargo tanks

(1) Every new oil tanker shall comply with the provisions of this regulation.
Every existing oil tanker shall comply with the provisions of this regulation
by the 2 October 1985 if-

   (a)  it was delivered to its first owner after 1 January 1977; or

   (b)  it was delivered to its first owner on or before-

        (i)    1 January 1977; and

        (ii)   the building contract for the tanker was placed after 1 January
               1974, or in cases where there was no building contract the keel
               was laid or the tanker was at a similar stage of construction
               after 30 June 1974.

(2) Cargo tanks of oil tankers shall be of such size and arrangements that the
hypothetical outflow Oc or Os, calculated in accordance with the provisions of
regulation 27(1)(b), anywhere in the length of the ship does not exceed 30000
cubic metres or 400 (DW)1/3, whichever is the greater, but subject to a
maximum of 40000 cubic metres.

(3) The volume of any one wing cargo oil tank of an oil tanker shall not
exceed 75 per cent of the limits of the hypothetical outflow Oc or Os referred
to in paragraph (2) of this regulation. The volume of any one centre cargo oil
tank shall not exceed 50000 cubic metres. However, in segregated ballast
oil tankers as defined in regulation 18 of these Regulations the permitted
volume of a wing cargo oil tank situated between two segregated ballast tanks,
each exceeding 1c in length may be increased to the maximum limit of
hypothetical oil outflow provided that the width of the wing tanks exceeds tc.

(4) The length of each cargo tank shall not exceed 10 metres or one of the
following values, whichever is the greater-

   (a)  where no longitudinal bulkhead is provided inside the cargo tanks- bi

(0.5 ____ + 0.1)L B but not to exceed 0.2 L

   (b)  where a centreline longitudinal bulkhead is provided inside the cargo
        tanks- bi

(0.25 ____ + 0.15)L B

   (c)  where 2 or more longitudinal bulkheads are provided inside the cargo
        tanks-

        (i)    for wing cargo tanks- 0.2L

        (ii)   for centre cargo tanks- bi 1

(1) if _____ is equal to or greater than ____ ____ B 5 0.2L bi 1

(2) if _____ is less than ____ ____ B 5 where no centreline longitudinal
bulkhead is provided- bi bi

(0.5 ____ + 0.1)L B where a centreline longitudinal bulkhead is provided- bi
bi

(0.25 ____ + 0.15)L B where "bi" is the minimum distance from the ship's side
to the outer longitudinal bulkhead of the tank in question measured inboard at
right angles to the centreline at the level corresponding to the assigned
summer freeboard. (L.N. 641 of 1994)

(5) In order not to exceed the volume limits established by paragraphs

(2), (3) and (4) of this regulation and irrespective of the type of cargo
transfer system installed, when such a system inter-connects two or more cargo
tanks, valves or other similar closing devices shall be provided for
separating the tanks from each other. These valves or devices shall be closed
when the tanker is at sea.

(6) Lines of piping which run through cargo tanks in a position less than tc
from the ship's side or less than vs from the ship's bottom shall be fitted
with valves or similar closing devices at the point at which they open into
any cargo tank. These valves shall be kept closed at sea at any time when the
tanks contain cargo oil, except that they may be opened for cargo transfer
needed for the purpose of trimming of the ship. (L.N. 177 of 1991)