A. A motorboat shall not be required to be numbered under this Part if it is:
(1) Already covered by a number in full force and effect which has been awarded to it pursuant to federal law or a federally approved numbering system of another state; however, such boat shall not have been within this state for a period in excess of ninety consecutive days.
(2) A motorboat from a country other than the United States temporarily using the waters of this state.
(3) A public vessel of the United States, a state, or a subdivision thereof.
(4) A ship's lifeboat.
B. A sailboat shall not be required to be numbered under this Part if it is:
(1) Twelve feet or less in length.
(2) A vessel commonly known as a sailboard, where the craft is designed for one person and operated in the standing position.