ARTICLE 52Duration of Certificates.
Certificates shall not be issued for a period of more than twelve months.
If a ship at the time when its certificate expires is not in a port of the country in which it is registered the certificate may be extended by a duly authorised officer of the country to which the ship belongs; but such extension shall be granted only for the purpose of allowing the ship to complete its return voyage to its own country, and then only in cases in which it appears proper and reasonable so to do.
No certificate shall be extended for a longer period than five months, and a ship to which such extension is granted shall not, on returning to its own country, be entitled by virtue of such extension to leave the country again without having obtained a new certificate.