48. Port-due not to be chargeable in certain cases.- No port-due shall be chargeable in respect of- (a) any pleasure-yacht, or (b) any vessel which. having left any port., is compelled to re-enter it by stress of whether or in consequence of having sustained any damage, or (c) any vessel which, having entered any port in the territories which, immediately before the 1st November, 1956, were comprised in the States of Madras and Andhra or the Port of Gopalpur in the State of Orissa, leaves it within forty-eight hours without discharge or taking in any passengers or cargo. | 
