46 U.S.C. § 60301: Regular tonnage taxes

a vessel entering from a foreign port or place in North America, Central America, the West Indies Islands, the Bahama Islands, the Bermuda Islands, or the coast of South America bordering the Caribbean Sea; or a vessel of the United States; a recreational vessel (as defined in section 2101 of this title ); or a barge. A tax is imposed at the rate of 13.5 cents per ton, not to exceed a total of 67.5 cents per ton per year, for fiscal years 2006 through 2010, and 6 cents per ton, not to exceed a total of 30 cents per ton per year, for each fiscal year thereafter, on a vessel at each entry in a port of the United States from a foreign port or place not named in subsection (a)(1). Subsection (a) does not apply to a vessel entering other than by sea from a foreign port or place at which tonnage, lighthouse, or other equivalent taxes are not imposed on vessels of the United States.