31. — (1) The master of every Safety Convention ship not registered in the State shall produce to the officer of customs from whom a clearance of the ship is demanded in respect of an international voyage from a port in the State accepted Safety Convention certificates that are the equivalent of the certificates issued by the Minister under this Act that would be required to be in force in respect of the ship if she were a ship so registered; and a clearance shall not be granted, and the ship may be detained, until such certificates are so produced.

(2) The production of an accepted Safety Convention certificate being the equivalent of—

(a) a qualified certificate, or

(b) an exemption certificate, other than a certificate stating that a ship is wholly exempt from the provisions of the Safety Convention relating to F38[radiocommunications] and F39[navigation and tracking systems and equipment], shall not avail for the purposes of section 29 or section 30 of this Act unless there is also produced the corresponding exemption certificate or qualified certificate as the case may be.