561 



adjacent to such space, multiplied by Si as defined below and taking 

 for all other wing tanks involved in such a collision the value of the 

 actual full volume. 



Si = l-li/le 



Where 1;= length in metres of void space or segregated bal- 

 last tank under consideration. 



(3) (a) 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 volume 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 installation of such a 

 partial double bottom. 



(c) Suction wells may be neglected in the determination of the 

 value hi provided such wells are not excessive in area and extend 

 below the tank for a minimum 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, hj 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 connexion to the tank served to prevent oil outflow 

 in the event of damage to the piping. Such piping shall be in- 

 stalled 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 trimming of the ship. 



(4) In the case where bottom damage simultaneously involves four 

 centre tanks, the value of Os may be calculated according to the for- 

 mula 



Os=y4 (2ZiWi+2ZiCi) (III) 



(5) An Administration may credit as reducing oil outflow in case of 

 bottom damage, an installed cargo transfer system having an emer- 

 gency high suction in each cargo oil tank, capable of transferring from 

 a breached tank or tanks to segregated ballast tanks or to available 

 cargo tankao-e if it can be assured that such tanks will have sufficient 

 ullage. Credit for such a system would be governed by ability to trans- 

 fer in two hours of operation, oil equal to one half of the largest of 

 the breached tanks involved and by availability of equivalent receiv- 

 ing capacity in ballast or cargo tanks. The credit shall be confined to 

 permitting calculation of Os according to formula (III). The pipes 

 for such suctions 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 information concerning the arrange- 

 ments accepted by it, for circulation to other Parties to the Convention. 



REGULATION 24 



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 be required, within two 



