Postage on board ship

Postage on postal packets intended for delivery in this country and posted on a ship– (a) on the high seas, shall, in the absence of special arrangement to the contrary between the Postal administrations concerned, be prepaid by means of the postage stamps and according to the postal tariff of the country in which such ship is registered or, if chartered, by which it is chartered; (b) in harbour, shall be prepaid by means of the postage stamps, and according to the postal tariff of the country in the territorial waters of which such ship is. 17