Section 12(5)(b) in The Merchant Shipping (Amendment) Act, 2002
(b)where the ship is engaged on a short voyage and whose certificate has not been extended under clause (a), for a period up to one month from the date when the certificate would have expired: Provided that any extension granted under clause (a) shall cease to be operative upon the ship' s arrival at the port referred to in that clause: Provided further that no extension shall be granted under clause (b) in respect of a certificate extended under clause (a).