Section 26 in The Merchant Shipping (Prevention of Pollution by Oil from Ships) Rules, 2010
26. Limitations of Size and Arrangement of Cargo Tanks.
(1)Subject to the provisions of sub-rule (7) below,-(a)every oil tanker of one hundred and fifty gross tonnage and above delivered after 31st December, 1979, as defined in sub-rule (45) of rule IA; and(b)every oil tanker of one hundred and fifty gross tonnage and above delivered on or before 31st December, 1979, as defined in sub-rule (46) of rule lA,which fall into either of the following categories, namely:-(i)a tanker, the delivery of which is after 1st January, 1977, or(ii)a tanker to which both the following conditions apply:(A)delivery is not later than 1st January, 1977; and(B)the building contract is placed after 1st January, 1974, or in cases where no building contract has previously been placed, the keel is laid or the tanker is at a similar stage of construction after 30th June, 1974, shall comply with the provisions of this rule.(2)Cargo tanks of oil tankers shall be of such size and arrangements that the hypothetical outflow Oc or Os calculated in accordance with the provisions of rule 25 anywhere in the length of the ship does not exceed 30,000 cubic metres or 400 (DWT) 1/3, whichever is the greater, but subject to a maXimum of 40,000 cubic metres.(3)The volume of anyone wing cargo oil tank of an oil tanker shall not exceed seventy five per cent. of the limits of the hypothetical oil outflow referred to in sub-rule (2) and the volume of anyone centre cargo oil tank shall not exceed 50,000 cubic metres:Provided that in segregated ballast oil tankers as defined in rule 18, the permitted volume of a wing cargo oil tank situated between two segregated ballast tanks, each exceeding tc in length may be increased to the maximum limit of hypothetical oil outflow if the width of the wing tanks exceeds tc.(4)The length of each cargo tank, shall not exceed 10 m or one of the following values, whichever is the greater.-(a)where no longitudinal bulkhead is provided inside the cargo tanks:(0.5 bi/B + 0.1)L but not to exceed 0.2L(b)where a centerline longitudinal bulkhead is provided inside the cargo tanks:(0.25 bi/B + 0.15) L(c)Where two or more longitudinal bulkheads are provided inside the cargo tanks.-(i)for wing cargo tanks: 0.2L(A)if Bi/B is equal to or greater than one fifth: 0.2L(B)if Bi/B is less than one fifth-(I)where no centerline longitudinal bulkhead is provided:(ii)for centre cargo tanks.-(0.5 bi/B + 0.1)L(II)where a centerline longitudinal bulkhead is provided:(0.25 bi/B + 0.15)Lwhere bi is the minimum distance from the ship's side to the outer longitudinal bulkhead of the tank in question measured inboard at right angles to the centerline at the level corresponding to the assigned summer freeboard.(5)In order not to exceed the volume limits established by sub-rules (2), (3) and (4) and irrespective of the accepted type of cargo transfer system installed, when such system interconnects two or more separating the tanks from each other. These valves or devices shall be closed when the tanker is at sea.(6)Lines of piping which run through cargo tanks in a position less than tc from the ship's side or less than Vc from the ship's bottom shall be fitted with valves or closing devices at the point at which they open into any cargo tank and these valves shall be kept closed at sea at any time when the tanks contain cargo oil, except that they may be opened only for cargo transfer needed for the purpose of trimming of the ship.(7)This rule does not apply to oil tankers delivered on or after 1st January, 2010, as' defined in sub-rule (38) of rule lA
