Section 25(2) in The Merchant Shipping (Prevention of Pollution by Oil from Ships) Rules, 2010
(2)If a void space or segregated ballast tank of a length less than lcIc, as defined in rule 24, is located between wing oil tanks, Oc in formula (I) may be calculated on the basis of volume wi 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 Si as defined below and taking for all other wing tanks involved in such collision the value of the actual full volume.Si = 1 - li/lcwhere li = length, In metres, of void space or segregated ballast tank under consideration.
