(1) A Passenger Ship Safety Certificate, a Radio Certificate or an exemption certificate stating that a ship is wholly exempt from the provisions of the Safety Convention relating to radio-telegraphy, radio-telephony and direction finders shall be in force for one year, and a Safety Equipment Certificate, shall be in force for 2 years from the date of the issue of the certificate or for such shorter period as may be specified in the certificate; save that no such certificate shall remain in force after notice is given by the Minister, or such other person as the Minister may authorise for the purpose, to the owner, master or agent of the ship, in respect of which it has been issued that the Minister has cancelled the certificate.