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Regulation 21 
SPECIAL REQUIREMENTS FOR DRILLING RIGS AND OTHER PLATFORMS 
Fixed and floating drilling rigs when engaged in the exploration, exploitation 
and associated offshore processing of sea-bed mineral resources and other plat- 
forms shall comply with the requirements of this Annex applicable to ships of 
400 tons gross tonnage and above other than oil tankers, except that: 
(a) they shall be equipped as far as practicable with the installations required 
in Regulations 16 and 17 of this Annex; 
(ob) they shall keep a record of all operations involving oil or oily mixture 
discharges, in a form approved by the Administration; and 
(c) in any special area and subject to the provisions of Regulation 11 of this 
Annex, the discharge into the sea of oil or oily mixture shall be prohibited ex- 
cept when the oil content of the discharge without dilution does not exceed 15 
parts per million. 
CuaprTer III 
REQUIREMENTS FOR MINIMIZING O1L POLLUTION From O1L TankERS DUE TO 
Sipe aNnD Botton DAMAGES 
Regulation 22 
DAMAGE ASSUMPTIONS 
For the purpose of calculating hypothetical oil outflow from oil tankers, three 
dimensions of the extent of damage of a parallelepiped on the side and bottom of 
the ship are assumed as follows. In the case of bottom damages two conditions are 
set forth to be applied individually to the stated portions of the oil tanker. 
(a) Side damage: 
(i) Longitudinal extent (1,): 1427/3 or 14.5 metres, whichever is less. 
(ii) Transverse extent (¢.): B/5 or 11.5 metres, whichever is less. 
(Inboard from the ship’s side at right angles to the centreline 
at the level of the summer load line.) 
(iii) Vertical extent (v.): from the base line upward without limit. 
(b) Bottom damage: For 0.3L from the forward perpendicular of ship. Any other 
part of ship. 
(i) Longitudinal extent (/,): L/10, L/10 or 5 metres, whichever is less. 
(ii) Transverse extent (¢,): B/6 or 10 metres, whichever is less but not 
less than 5 metres, 5 metres. 
(iii) Vertical extent from the base line (v,): B/15 or 6 metres, whichever 
is less. 
(2) Wherever the symbols given in this Regulation appear in this Chapter, 
they have the meaning as defined in this Regulation. 
Regulation 23 
HYPOTHETICAL OUTFLOW OF OIL 
(1) The hypothetical outflow of oil in the case of side damage (O,) and bottom 
damage (O,) shall be calculated by the following formulae with respect to com- 
partments breached by damage to all conceivable locations along the length of 
the ship to the extent as defined in Regulation 22 of this Annex. 
(a) for side damages: 
0.=2Wit+2KiC; (I) 
0,=1/3(2Z2;Wi+ 2Z;C}) (II) 
(b) for bottom damages: 
where: 
W=volume of a wing tank in cubic metres assumed to be breached by the 
damage as specified in Regulation 22 of this Annex; W; for a segre- 
gated ballast tank may be taken equal to zero, 
C,=volume of a centre tank in cubic metres assumed to be breached by the 
damage as specified in Regulation 22 of this Annex; C; for a segregated 
ballast tank may be taken equal to zero, 
K,=1—(bi/te); when 5; is equal to or greater than ¢., K; shall be taken equal 
: to zero, 
Zi:=1—(hi/v.) ; when h, is equal to or greater than v,, Z; shall be taken equal 
to zero, 
