Section 28(2)(d) in The Merchant Shipping (Prevention of Pollution by Oil from Ships) Rules, 2010
(d)where the damage involving transverse bulkheads is envisaged as specified in clauses (a) and (b) above, transverse watertight bulkheads shall be spaced at least at a distance equal to the longitudinal extent of assumed damage specified in clause (a) in order to be considered effective and where transverse bulkheads are spaced at a lesser distance, one or more of these bulkheads within such extent of damage shall be assumed as non-existent for the purpose of determining flooded compartment;