Tennessee Code Title 69. Waters, Waterways, Drains and Levees § 69-9-206

(1) A vessel that has a valid document issued by the bureau of customs of the United States, or any federal agency successor to the bureau of customs must be registered with the agency but is not required to display the identification numbers on the vessel;

(2) A vessel with a valid number awarded to it pursuant to federal law or a federally-approved numbering system of another state; unless Tennessee has become the state of principal use and the vessel has been in Tennessee for sixty (60) days;

(3) A vessel from a country other than the United States temporarily using the waters of Tennessee;

(4) A vessel that is owned by the United States government, a state, or political subdivision of the United States government or a state that is used in the public service;

(5) A ship's lifeboat;

(6) A motorboat belonging to a class of boats that has been exempted from numbering by the commission after the agency has found that the numbering of motorboats of such class will not materially aid in their identification; and, if an agency of the federal government has a numbering system applicable to the class of motorboats to which the motorboat in question belongs, after the commission has further found that the motorboat would also be exempt from numbering if it were subject to the federal law; or

(7) A vessel that is owned by any volunteer rescue squad and used solely in emergency or rescue work and not for private, personal, recreation, or business use.