(2)Where a valid [passenger ship safety certificate or special trade passenger ship safety certificate] [ Substituted by Act 69 of 1976, Section 23, for " safety convention certificate" (w.e.f. 1.12.1976).] is produced in respect of a passenger ship other than an Indian ship and there is attached to the certificate a memorandum which-(a)has been issued by or under the authority of the Government of the country in which the ship is registered, and(b)modifies for the purpose of any particular voyage, in view of the number of persons actually carried on that voyage, the particulars stated in the certificate with respect to life saving appliances, the certificate shall have effect for the purpose of that voyage as if it were modified in accordance with the memorandum.