§ 185.402 § 185.402 Officers. Each officer employed on any vessel subject to this subchapter must have his or her license or merchant mariner credential onboard and available for examination at all times when the vessel is operating. [USCG-2006-24371, 74 FR 11267, Mar. 16, 2009]
46 CFR §185.402
46 CFR Part 185
TL;DR
Each officer employed on any vessel subject to this subchapter must have his or her license or merchant mariner credential onboard and available for examination at all times when the vessel is operating.