Section 162: For the purpose of this part-

(a) "goods subject to the Customs laws" includes all goods which, if discharged from the aircraft or ship in which the same are carried, would be required by law to be conveyed into a Customs area and all goods loaded on an aircraft or ship, or brought to a Customs area, wharf, quay or other place to be loaded on board an aircraft or ship, for exportation or use as an aircraft's or a ship's stores. The onus of proof in any proceedings that any such goods were not subject to the Customs laws, or that any goods loaded on an aircraft or ship or brought to any Customs area, wharf, quay or other place were not so loaded as stores, or for the purpose of being exported, or were not brought to be loaded as atoresaid for the purpose of being exported or used as an aircraft's or a ship's stores, shaH be on the defendant, and . (b) "boat" includes hghters and barges irrespective of their size and all ·canoes and other floating craft of any description, not exceeding one hundred tons burden, but shall not include any boat owned by Government when used in the service of Government.