Whoever intentionally destroys, seriously damages, alters, moves, or tampers with any aid to maritime navigation maintained by the Great Lakes St. Lawrence Seaway Development Corporation under the authority of section 4 of the Act of May 13, 1954 (33 U.S.C. 984), by the Coast Guard pursuant to section 81 1

of title 14, United States Code, or lawfully maintained under authority granted by the Coast Guard pursuant to section 83 of title 14, United States Code, if such act endangers or is likely to endanger the safe navigation of a ship, shall be fined under this title or imprisoned for not more than 20 years, or both.