46 U.S.C. § 55334 — Restrictions on operations

1. (a)ProhibitionsExcept as provided in subsection (b), an American Great Lakes vessel may not be used to—
   1. (1)engage in trade—
      1. (A)from a port in the United States that is not located on the Great Lakes; or
      2. (B)between ports in the United States;
   2. (2)transport bulk cargo (as defined in section 40102 of this title) that is subject to section 55305 or 55314 of this title or section 2631 of title 10; or
   3. (3)provide a service (except ocean freight service) as—
      1. (A)a contract carrier; or
      2. (B)a common carrier on a fixed advertised schedule offering frequent sailings at regular intervals in the foreign trade of the United States.
2. (b)Off-Season ExceptionAn American Great Lakes vessel may be used for not more than 90 days during any 12-month period to engage in trade prohibited by subsection (a)(1)(A), except during the Great Lakes shipping season.