Neb. Rev. Stat. § 37-1249

A vessel shall not be required to be numbered pursuant to the State Boat Act 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 and if such boat has not been within this state for a period in excess of sixty consecutive days; (2) A vessel from a country other than the United States temporarily using the waters of this state; (3) A vessel whose owner is the United States, a state, or a subdivision thereof; or (4) A ship's lifeboat.