Section 5(3) in The Merchant Shipping (Tonnage Measurement Of Ships) Rules, 1960
(3)The allowance made under this head shall not in any case exceed fifty-five per cent of that portion of the tonnage of the ship which remains after deducting from the gross tonnage the allowance on account of the space used for the accommodation of the master and the crew provided that this shall not apply to ships constructed for the purpose of towing vessels so long as they are employed as tugs but not employed for the carriage of passengers, cargo or stores or when using dry docks, floating docks or places provided for repairing of vessels.
