17.—(1) Subject to the following paragraphs and to regulation 18, the duration of an International Load Line Certificate is for such period as is specified in the certificate, not exceeding five years beginning with the date of completion of the initial or renewal survey.
(2) Subject to regulation 18(9), where a renewal survey is completed within three months before the expiry of the existing certificate, the new certificate is valid for a period beginning with the date of completion of the renewal survey and ending on a date which does not exceed five years from the expiry of the existing certificate.
(3) Subject to regulation 18(9), where a renewal survey is completed after the expiry of the existing certificate, the new certificate is valid for a period beginning with the date of completion of the renewal survey and ending on a date which does not exceed five years from the expiry of the existing certificate.
(4) Subject to regulation 18(9), where a renewal survey is completed more than three months before the expiry of the existing certificate, the new certificate is valid for a period beginning with the date of completion of the renewal survey and ending on a date which does not exceed five years from the date of completion of that renewal survey.