Section 2(c) in The Merchant Shipping (Tonnage Measurement Of Ships) Rules, 1960
(c)"continuous deck" includes a deck continuous athwartship and in a fore and aft direction, at least between peak bulkheads, with interruptions in way of propelling machinery space, openings, leader and stairway, openings, trunks, chain lockers, cofferdams or steps which do not exceed 1220 millimetres in height :
