In case of proceedings for registration of the vessel, for 6 months from the date of issue of the provisional certificate of nationality or until the vessel arrives at any port in India or Pakistan, whichever is earlier, to operate the vessel under the provisional certificate of nationality. will be obtained and in such cases the temporary certificate of nationality will be treated as a certificate of registration. However, except in clause (b) of sub-section (1) of section 16, no vessel shall obtain a temporary certificate more than once.