The Enforcement Rules of the Ship Registration Law Article 30

When making the proprietorship registration of a ship during construction, which has been mortgaged, the registration of the mortgage shall be transferred to the ship's register book after completing such registration, of which the date shall be noted, and the title chop of person in charge shall be affixed.After making the above registration, the special register book shall be closed.If the ship's port of registry is beyond the jurisdiction of the Shipping Administration Authority registering such mortgage mentioned hereinbefore, the person in charges of the port of registry shall transfer the information of the mortgage to the register book according to the transcript of the special register book issued by the former Shipping Administration Authority.
中文原文 船舶登記法施行細則第30條
在建造中已有抵押權登記之船舶為所有權登記時,應於登記所有權後,將抵押權之登記移載於船舶登記簿,並記明年、月、日,由主辦人員加蓋職名章。
為前項登記後,特別登記簿之記載應即截止。
第一項之登記,其船籍港不屬於登記抵押權之航政主管機關時,船籍港主辦人員應依建造中抵押權登記之航政機關所發特別登記簿之謄本,將其抵押之事項轉載於登記簿。

English translation for reference only; the Chinese text prevails. Not legal advice.