Notwithstanding anything contained in section ¹[255] or section 279; where any ship has been advertised under section ¹[255] for the conveyance of pilgrims has been or is likely to be delayed beyond the advertised final date of sailing, the owner or agent may, with the permission in writing of the pilgrim officer, substitute for it any other ship which is capable of carrying not less than the same number of pilgrims of each class, and on such permission being given the advertisement shall be deemed to have been made in respect of the ship so substituted, and all the provisions of those sections shall apply accordingly in respect of such ship.