283 



(2) Cargo tanks of oil tankers shall be of such size and arransement.s that the 

 hypothetical outflow Oc or Os calculated in accordance with the provisions *of 

 Regulation 25 of this Annex any where in the length of the ship does not exceed 

 30,000 cubic metres or 400-v^DW, whichever is the greater, but subject to a maxi- 

 mum of 40,000 cubic metres. 



(3) The volume of any one wing cargo oil tank of an oil tanker shall not ex- 

 ceed seventy-five percent of the limits of the hypothetical oil outflow referred 

 to in paragraph (2) of this Regulation. The volume of any one centre cargo oil 

 tank shall not exceed 50,000 cubic metres. 



(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 longtiudinal bulkhead is provided : O.IL 



(b) where a longitudinal bulkhead is provided at the centreline only : 0.15L 



(c) where two or more longitudinal bulkheads are provided: 

 (i) for wing tanks: 0.2L 



(ii) for centre tanks: 



(a. a) if bi/Bisequal to or greater than 1/5: 0.2L 

 (b.b) if b,/B is less than 1/5 : 

 where no centreline longitudinal bulkhead is provided : (0.5 bi/B-fODL 

 where a centreline longitudinal bulkhead is provided: (0.25 bi/B 

 +0.15 )L 



REGULATION 25. — StJBDIVISION AND STABILITY'"' 



(1) Every new oil tanker shall comply with the subdivision and damage sta- 

 bility criteria as specified in paragraph (3) of this Regulation after the assumed 

 side or bottom damage as si>ecified in paragraph (2) of this Regulation, for any 

 operating draught reflecting actual partial or full load conditions consistent 

 with trim and strength of the ship as well as specific gravities of the cargo. 

 Such damage shall be applied to all conceivable locations along the length. of 

 the ship as follows : 



(a) in ships of more than 225 metres in length, anywhere in the ship's length ; 



(b) in ships of more than 150 metres, but not exceeding 225 metres in length, 

 anywhere in the ship's length except involving either after or forward bulkhead 

 bounding the machinery space located aft. The machinery space shall be. treated 

 as a" single floodable compartment : 



(c) in ships not exceeding 150 metres in length, anywhere in the ship's length 

 l)etween adjacent transverse bulkheads with the exception of the machinery 

 space. For ships of 100 metres or less in length where all requirements of para- 

 graph (3) of this Regulation caimot be fulfilled without materially impairing 

 the operational qualities of the ship, Administrations may allow relaxations 

 from these requirements. 



Ballast conditions where the ship is not carrying oil in cargo tanks excluding 

 any oily residues, shall not be considered. 



(2) The following provisions regarding the extent and the character of the 

 assumed damage shall apply : 



(a) the extent of side or bottom" damage shall be as specified in Regulation 

 22 of this Annex.^" If any damage of les.ser extent would result in a more severe 

 condition such damage shall be assumed ; 



(b) where the damage involving transverse bulkheads is envisaged as specified 

 in sub-paragraphs (1) (a) and (b) of this Regulation, tran.sverse watertight 

 l)ulkheads shall be spaced at least at a distance equal to the longitudinal extent 

 of assumed damage specified in Regulation 22(a) (i) of this Annex, in order 

 to be considered effective. Where transverse bulkheads are spaced at a lesser 

 distance, one or more of these bulkheads within such extent of damage shall be 

 as.sumed as non-existent for the purpose of determining flooded compartments. 



*' Tlip possible Implications of thp rennirements of this Regulation on the design of 

 sepresratpfi bnU.ist tankers should he invostisrated. 



*" Several delegations considered that the adoption of bottom damage length as drafted 

 in Regulation 22(b) of this Annex has resulted in a eonflict with the requirements for the 

 spaeintr of transverse bulkheads as si)eritie(l in sub-paragraphs (b) and (c) of this para- 

 graph with regard to side damasre. Investigations should he made, tlierefore, on the inii>lica- 

 fions of using the bottom da mace length given in Regulation 22(b) in this context, 

 particularly with reference tf) such daniaue within forward 0..'?Ij of the ship. 



■"'" Although man.v delegations iireferred the assumed longitudinal extent of side damage 

 as provided for in the IflflO Safety Convention, it was considered expedient to use the 

 loncritudinal extent referred to in Regulation 22 of this Annex only for the sake of con- 

 sistency throughout the Marine Pollution Convention. 



26-282 O - 74 - 20 



