10.—(1) Where alterations are made in the arrangement, construction, capacity, use of spaces, total number of passengers the ship is permitted to carry under the terms of the ship’s passenger certificate, assigned load line, or permitted draught of the ship such as would cause an increase in the gross or net tonnage, the existing International Tonnage Certificate (1969) shall cease to be valid and shall be delivered up to and cancelled by the Certifying Authority.
(2) When a ship is transferred from the United Kingdom Register the International Tonnage Certificate (1969) shall cease to be valid except when the transfer is to the Administration of a state which is a Contracting Government, in which case the certificate may remain in force for a period not exceeding 3 months or until the new Administration issues another International Tonnage Certificate (1969), whichever is the earlier. The Certifying Authority shall transmit to the Administration of that Government as soon as possible after the transfer has taken place a copy of the certificate carried by the ship at the time of transfer and a copy of the relevant tonnage calculations.