The following vessels shall be exempt from registration and display of a boat fee decal in this state:
I. Sailboats under 12 feet in length, rowboats and canoes powered by sail, oars, paddles, or other human power. Any vessel which has an inboard or outboard motor shall not be exempt from registration except as provided in paragraph II.
II. Vessels registered in another state or country temporarily using the waters of this state for not more than 30 consecutive days.
III. Vessels owned or operated by the United States government.