(a) Except as provided in § 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 of principal operation; and

(2) The number is displayed as described in § 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 of principal operation.