(1)Every certificate issued in respect of a ship under clause (a) or clause (b) of sub-section (1) of section 316 and every certificate issued under clause (aa) of that sub-section to a ship referred to in clause (e) of sub-section (3) of section 310 shall be in force for a period of five years from the date of its issue or for such shorter period as may be specified in the certificate but subject to the provisions of this Part, a new certificate may be issued in respect of such ship:Provided that where it is not possible to issue such new certificate to any ship before the expiry of its existing certificate, the Central Government or any other person authorised by it to issue such certificate may, on being satisfied that no alterations affecting the ship's free board have been made in the structure, equipment, arrangements, material or scantlings, after the last survey of the ship under sub-section (5), extend the validity of the existing certificate for such period not exceeding five months as the Central Government or such person may deem fit:][Provided further that when the survey for the purpose of issue of certificate under sub-section (1) of section 316 is completed within three months before the expiry date of the existing certificate, the new certificate may be valid from the date of completion of such survey to a date not exceeding five years from the date of expiry of the existing certificate.] [ Inserted by Act 63 of 2002, Section 14 (w.e.f. 1.2.2003).]
