A vessel shall not be required to be numbered under this chapter if it is:
(1) Already covered by a number in full force and effect which has been issued to it pursuant to federal law or a federally approved numbering system of another state, provided that such vessel shall not have been within this state for a period in excess of sixty (60) consecutive days.
(2) A vessel from a country other than the United States using the waters of this state for a period of less than sixty-one (61) consecutive days.
(3) A vessel which is owned by the United States, another state or a political subdivision thereof.
(4) A vessel’s lifeboat.
(5) A vessel belonging to a class of vessels which has been exempted from numbering by the department after it has found that the numbering of vessels of such class will not materially aid in their identification and has further found that the vessel would also be exempt from numbering if it were subject to federal law.
(6) A float tube.