This Part applies only to sea-going passenger ships fitted with mechanical means of propulsion, but the provisions of this Part relating to [special trade passenger ships] shall not apply-

(a) to any such ship not carrying more than thirty unberthed passengers; or

(b) to any such ship not intended to carry [special trade passengers] [Substituted by Act 69 of 1976, Section 2, for " unberthed passenger ships " and " unberthed passengers " , respectively (w.e.f. 1.12.1976).] to or from any port or place in India.