(a) Vessels having a valid marine document issued by the United States or a foreign government, while being used for commercial purposes.

(b) Vessels displaying a valid identification or registration number issued by another state under a numbering system which has been approved in accordance with the provisions of federal law, provided such vessel shall not have been within this state for a period in excess of ninety consecutive days.

(c) Vessels owned by residents of foreign countries temporarily using the waters of the state.

(d) Vessels owned by the United States, a state, or a subdivision thereof.

(e) Boats which are "lifeboats." No vessel which is used for other than lifesaving purposes shall be deemed a "lifeboat" for purposes of this subdivision.

(f) Vessels used exclusively for racing.

(g) Any vessel which is not equipped with a motor by which it may be mechanically propelled. 2. Notwithstanding the provisions of subdivision one of this section, the owner of a vessel which is exempt from the provisions of section twenty-two hundred fifty-one of this article may apply for, and the commissioner may issue, a registration for such vessel. If such a registration is issued, and while such registration is in effect, the provisions of this article relating to certificates of registration, registration numbers and validating stickers shall apply to such vessel. Upon the expiration of the registration of any such vessel, the registration number assigned to it shall be effectively removed from such vessel.