1 This
regulation shall apply to oil tankers of 600 tonnes deadweight and
above delivered on or after 6 July 1996, as defined in regulation 1.28.6, as follows:
2 Every
oil tanker of 5,000 tonnes deadweight and above shall:
-
.1 in lieu of paragraphs 12 to 15 of regulation 18, as applicable, comply
with the requirements of paragraph 3 of this regulation unless it
is subject to the provisions of paragraphs 4 and 5 of this regulation;
and
-
.2 comply, if applicable, with the requirements of
regulation 28.7.
3 The entire cargo
tank length shall be protected by ballast tanks or spaces other than
tanks that carry oil as follows:
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.1 Wing tanks or spaces
Wing tanks or spaces shall extend either for the full depth
of the ship's side or from the top of the double bottom to the uppermost
deck, disregarding a rounded gunwale where fitted. They shall be arranged
such that the cargo tanks are located inboard of the moulded line
of the side shell plating nowhere less than the distance w which,
as shown in figure 1 is measured
at any cross-section at right angles to the side shell, as specified
below:
|
w
|
= |
|
|
w
|
= |
2,0
m, whichever is the lesser. |
The minimum value of w = 1.0 m.
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.2 Double bottom tanks or spaces
At any cross-section the depth of each double bottom tank or
space shall be such that the distance h between the bottom
of the cargo tanks and the moulded line of the bottom shell plating
measured at right angles to the bottom shell plating as shown in figure 1 is not less than specified
below:
|
h
|
= |
2.0
m, whichever is the lesser. |
The minimum value of h = 1.0 m.
-
.3 Turn of the bilge area or at locations without
a clearly defined turn of the bilge
When the distances h and w are different,
the distance w shall have preference at levels exceeding
1.5h above the baseline as shown in figure 1.
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SEE INTERPRETATION 39
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.4 The aggregate capacity of ballast tanks
On crude oil tankers of 20,000 tonnes deadweight and above and
product carriers of 30,000 tonnes deadweight and above, the aggregate
capacity of wing tanks, double bottom tanks, forepeak tanks and after
peak tanks shall not be less than the capacity of segregated ballast
tanks necessary to meet the requirements of regulation 18 of this Annex. Wing
tanks or spaces and double bottom tanks used to meet the requirements
of regulation 18 shall be
located as uniformly as practicable along the cargo tank length. Additional
segregated ballast capacity provided for reducing longitudinal hull
girder bending stress, trim, etc., may be located anywhere within
the ship.
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.5 Suction wells in cargo tanks
Suction wells in cargo tanks may protrude into the double bottom
below the boundary line defined by the distance h provided that such
wells are as small as practicable and the distance between the well
bottom and bottom shell plating is not less than 0.5h.
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.6 Ballast and cargo piping
Ballast piping and other piping such as sounding and vent piping
to ballast tanks shall not pass through cargo tanks. Cargo piping
and similar piping to cargo tanks shall not pass through ballast tanks.
Exemptions to this requirement may be granted for short lengths of
piping, provided that they are completely welded or equivalent.
4 The following applies
for double bottom tanks or spaces:
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.1 Double bottom tanks or spaces as required by
paragraph 3.2 of this regulation may be dispensed with, provided that
the design of the tanker is such that the cargo and vapour pressure
exerted on the bottom shell plating forming a single boundary between
the cargo and the sea does not exceed the external hydrostatic water
pressure, as expressed by the following formula:
ƒ x
h
c
x
ρ
c
x g + p ≤ d
n
x
ρ
s
x
g
- where:
|
h
c
|
= |
height of cargo in contract with the bottom shell plating in
metres |
|
ρ
c
|
= |
maximum cargo density in kg/m3
|
|
d
n
|
= |
minimum operating draught under any expected loading condition
in metres |
|
ρ
s
|
= |
density of seawater in kg/m3
|
|
p
|
= |
maximum
set pressure above atmospheric pressure (gauge pressure) of pressure/vacuum
valve provided for the cargo tank in pascals |
|
ƒ |
= |
safety factor
= 1.1 |
|
g
|
= |
standard
acceleration of gravity (9.81 m/s2)
|
-
.2 Any horizontal partition necessary to fulfil
the above requirements shall be located at a height not less than B/6 or 6 m, whichever is the lesser, but not more than 0.6D,
above the baseline where D is the moulded depth amidships.
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.3 The location of wing tanks or spaces shall
be as defined in paragraph 3.1 of this regulation except that, below
a level 1.5 h above the baseline where h is
as defined in paragraph 3.2 of this regulation, the cargo tank boundary
line may be vertical down to the bottom plating, as shown in figure 2.
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SEE INTERPRETATION 40
5 Other
methods of design and construction of oil tankers may also be accepted
as alternatives to the requirements prescribed in paragraph 3 of this
regulation, provided that such methods ensure at least the same level
of protection against oil pollution in the event of collision or stranding
and are approved in principle by the Marine Environment Protection
Committee based on guidelines developed by the Organization. footnote
6 Every oil tanker
of less than 5,000 tonnes deadweight shall comply with paragraphs
3 and 4 of this regulation, or shall:
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.1 at least be fitted with double bottom tanks
or spaces having such a depth that the distance h specified in paragraph
3.2 of this regulation, complies with the following:
with a minimum value of h = 0.76 m;
in the turn of the bilge area and at locations without a clearly
defined turn of the bilge, the cargo tank boundary line shall run
parallel to the line of the midship flat bottom as shown in figure 3; and
-
.2 be provided with cargo tanks so arranged that
the capacity of each cargo tank does not exceed 700 m3 unless
wing tanks or spaces are arranged in accordance with paragraph 3.1
of this regulation, complying with the following:
|
w |
= |
|
7 Oil shall
not be carried in any space extending forward of a collision bulkhead
located in accordance with regulation II-1/11 of
the International Convention for the Safety of Life at Sea, 1974,
as amended. An oil tanker that is not required to have a collision
bulkhead in accordance with that regulation shall not carry oil in
any space extending forward of the transverse plane perpendicular
to the centreline that is located as if it were a collision bulkhead
located in accordance with that regulation.
8 In approving the
design and construction of oil tankers to be built in accordance with
the provisions of this regulation, Administrations shall have due
regard to the general safety aspects including the need for the maintenance
and inspections of wing and double bottom tanks or spaces.
Figure 1 Cargo tank boundary lines for the purpose of paragraph 3
Figure 2 Cargo tank boundary lines for the purpose of paragraph 4
Figure 3 Cargo tank boundary lines for the purpose of paragraph 6