Regulation 18

When the characteristics of a ship, such as V, Vc, d, N1 or N2 as defined in regulations 15 and 16, are altered and where such an alteration results in an increase in its net tonnage as determined in accordance with regulation 16, the net tonnage of the ship corresponding to the new characteristics shall be determined and shall be applied without delay.

A ship to which load lines referred to in regulation 16(2)(a) and (b) are concurrently assigned shall be given only one net tonnage as determined in accordance with the provisions of regulation 16 and that tonnage shall be the tonnage applicable to the appropriate assigned load line for the trade in which the ship is engaged.

When the characteristics of a ship such as V, Vc, d, N1 or N2 as defined in regulations 15 and 16 are altered or when the appropriate assigned load line referred to in paragraph (2) is altered due to the change of the trade in which the ship is engaged, and where such an alteration results in a decrease in its net tonnage as determined in accordance with regulation 16, a new International Tonnage Certificate (1969) or a new Singapore Tonnage Certificate incorporating the net tonnage so determined shall not be issued until 12 months have elapsed from the date on which the current Certificate was issued:Provided that this requirement shall not apply —