68 FOREIGN TRADE ZONES It is important to bear in mind that a vessel is earning revenue only when in motion. The service which it performs consists of carrying goods from one place to another, and it is evident that the amount of cargo it can carry per year and its gross revenue are both directly affected by the number of trips it can make on a given route. Time in port is unproductive and should be reduced to the minimum necessary to discharge the vessel and take on new cargo, fuel, and supplies. Under existing customs rules, the master of a vessel carry- ing bonded merchandise or foreign merchandise for which entry has not been made must report its arrival at the customhouse within 24 hours (or as soon thereafter as official business hours will permit), unless the vessel has already been boarded by a duly authorized cus- toms official. If the vessel arrives after regular hours or on holidays, preliminary entry prior to formal entry may be made only by giving bond. In lieu of bond given on each application, a term bond may be accepted in the sum of $10,000 for bulk cargoes and $50,000 for general cargoes to cover vessels carrying such cargoes within one year from the date thereof. The master of the vessel must submit an inward foreign manifest. After this manifest has been sworn to by the master, the boarding officer checks the articles with the manifest and places under seal those which are not to be landed. Vessels arriving from foreign ports may retain on board without payment of duty coal and other fuel supplies, ships’ stores, sea stores and legitimate equipment. If any other, or greater quantity of sea stores, ships’ stores, bunker coal, or bunker oil is found on board than is specified in ship’s mani- fest, or if any such articles, whether shown on the manifest or not, are landed without a permit issued by the collector, all such articles omitted from the manifest or landed without a permit are subject to forfeiture, and the master will be liable to a penalty equal to the value of the articles. Tonnage tawes—A tonnage duty of 2 cents per net ton not to exceed in the aggregate 10 cents in any one year is imposed at each entry on all vessels which shall be entered in any port of the United States from any foreign port or place in North America, Central America, the Bahama Islands, the West Indies, the Bermuda Islands, Newfoundland, or the coast of South America bordering on the Caribbean Sea above and including the mouth of the Orinoco River, and regularly documented American, Norwegian, or Swedish vessels entering directly from Norway or Sweden with cargo obtained in Norway or/and Sweden; and a duty of 6 cents per net ton, not to exceed 30 cents per net ton per annum, is imposed at each entry on all vessels which are entered in any port of the United States from any other foreign port. Vessels are exempt from this tonnage duty when arriving otherwise than by sea from foreign ports at which.