(1) For the purpose of registry of an alteration in a ship the ship's certificate of registry shall be produced to the registrar, and the registrar shall, in his discretion, either retain the certificate of registry and grant a new certificate of registry containing a description of the ship as altered or endorse and sign on the existing certificate a memorandum of the alteration.
     (2) The particulars of the alteration so made, and the fact of the new certificate having been granted, or endorsement having been made, shall be entered by the registrar of the ship's port of registry in his register book; and for that purpose the registrar to whom the application for the registry of the alteration has been made (if he is not the registrar of the ship's port of registry) shall forthwith report to the last mentioned registrar the particulars and facts as aforesaid, accompanied, where a new certificate of registry has been granted, by the old certificate of registry.