46 U.S.C. § 12502

1. (a)For the identification of a vessel of the United States, the Secretary of Transportation—
   1. (1)shall maintain a unique numbering system and assign a number to each vessel of the United States;
   2. (2)may maintain a system of signal letters for a documented vessel;
   3. (3)shall record a name selected by the owner of a documented vessel approved by the Secretary as the vessel’s name of record; and
   4. (4)may establish other identification markings.
2. (b)The manufacturer or owner of a vessel shall affix to the vessel and maintain in the manner prescribed by the Secretary the number assigned and any other markings the Secretary may require.
3. (c)Once a number is assigned under this section, it may not be used by another vessel.
4. (d)Once a documented vessel’s name is established, the name may not be changed without the approval of the Secretary.
5. (e)A person may not tamper with or falsify a number or other marking required under this section.