[Code of Federal Regulations] [Title 33, Volume 2] [Revised as of July 1, 2003] From the U.S. Government Printing Office via GPO Access [CITE: 33CFR173.15] [Page 802] TITLE 33--NAVIGATION AND NAVIGABLE WATERS CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PART 173--VESSEL NUMBERING AND CASUALTY AND ACCIDENT REPORTING--Table of Contents Subpart B--Numbering Sec. 173.15 Vessel number required. (a) Except as provided in Sec. 173.17, no person may use a vessel to which this part applies unless: (1) It has a number issued on a certificate of number by the issuing authority in the State in which the vessel is principally used; and (2) The number is displayed as described in Sec. 173.27. (b) This section does not apply to a vessel for which a valid temporary certificate has been issued to its owner by the issuing authority in the State in which the vessel is principally used.