108 
b;=width of wing tank in metres under consideration measured inboard 
from the ship’s side at right angles to the centreline at the level 
corresponding to the assigned summer freeboard. 
hy=minimum depth of the double bottom in metres under consideration ; 
where no double bottom is fitted hy shall be taken equal to zero, 
Whenever symbols given in this paragraph appear in this chapter, they have 
the meaning as defined in this Regulation. 
(2) If a void space or segregated ballast tank of a length less than 7. as 
defined in Regulation 22 of this Annex is located between wing oil tanks, O. in 
formula (I) may be calculated on the basis of volume W, being the actual 
volume of one such tank (where they are of equal capacity) or the smaller of 
the two tanks (if they differ in capacity), adjacent to such space, multiplied 
by S; as defined below and taking for all other wing tanks involved in such a 
collision the value of the actual full volume. 
Si:=1—1,/l. 
where: /,=length in metres of void space or segregated ballast tank under 
consideration. 
(3) (@) Credit shall only be given in respect of double bottom tanks which 
are either empty or carrying clean water when cargo is carried in the tanks 
above. 
(b) Where the double bottom does not extend for the full length and width 
of the tank involved, the double bottom is considered non-existent and the vol- 
ume of the tanks above the area of the bottom damage shall be included in 
formula (II) even if the tank is not considered breached because of the installa- 
tion of such a partial double bottom. 
(c) Suction wells may be neglected in the determination of the value hi, pro- 
vided such wells are not excessive in area and extend below the tank for a mini- 
mum distance and in no case more than half the height of the double bottom. If 
the depth of such a well exceeds half the height of the double bottom, h; shall be 
taken equal to the double bottom height minus the well height. 
Piping serving such wells if installed within the double bottom shall be fitted 
with valves or other closing arrangements located at the point of connection to 
the tank served to prevent oil outflow in the event of damage to the piping. Such 
piping shall be installed as high from the bottom shell as possible. These valves 
shall be kept closed at sea at any time when the tank contains oil cargo, except 
that they may be opened only for cargo transfer needed for the purpose of trim- 
ming of the ship. 
(4) In the case where bottom damage simultaneously involves four centre 
tanks, the value of O, may be calculated according to the formula 
0,=1/4(2Z,;Wy+2Z,C;) (111) 
(5) An Administration may credit as reducing oil outflow in case of bottom 
damage, an installed cargo transfer system having an emergency high suction 
in each cargo oil tank, capable of transferring from a breached tank or tanks to 
segregated ballast tanks or to available cargo tankage if it can be assured that 
such tanks will have sufficient ullage. Credit for such a system would be gov- 
erned by ability to transfer in two hours of operation, oil equal to one half of 
the largest of the breached tanks involved and by availability of equivalent re- 
ceiving capacity in ballast or cargo tanks. The credit shall be confined to per- 
mitting calculation of O, according to formula (TIT). The pipes for such sue- 
tions shall be installed at least at a height not less than the vertical extent of the 
bottom damage vs. The Administration shall supply the Organization with the in- 
formation concerning the arrangements accepted by it, for circulation to other 
Parties to the Convention. 
Regulation 24 
LIMITATION OF SIZE AND ARRANGEMENT OF OARGO TANKS 
(1) Every new oil tanker shall comply with the provisions of this Regulation. 
Overy existing oil tanker shall be required, within two years after the date of 
entry into force of the present Convention, to comply with the provisions of this 
Regulation if such a tanker falls into either of the following categories: 
(a) a tanker, the delivery of which is after 1 January 1977; or 
(b) a tanker to which both the following conditions apply : 
(i) delivery is not later than 1 January 1977 and 
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