46 U.S.C. § 60301

(a) Lower Rate .— A tax is imposed at the rate of 4.5 cents per ton, not to exceed a total of 22.5 cents per ton per year, for fiscal years 2006 through 2010, and 2 cents per ton, not to exceed a total of 10 cents per ton per year, for each fiscal year thereafter, at each entry in a port of the United States of— (1) 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 (2) a vessel returning to the same port or place in the United States from which it departed, and not entering the United States from another port or place, except— (A) a vessel of the United States; (B) a recreational vessel (as defined in section 2101 of this title ); or (C) a barge. (b) Higher Rate .— 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). (c) Exception for Vessels Entering Other Than by Sea .— 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.