33 CFR 95.015 : Navigation And Navigable Waters (§ 1.01-1 To Parts 404-499) — (§ 1.01-1 To Parts 121-124) — Coast Guard, Department Of Homeland Security (§ 1.01-1 To Parts 121-124) — Vessel Operating Regulations (§ 95.001 To Subpart B) — Operating A Vessel While Under The Influence Of Alcohol Or A Dangerous Drug (§ 95.001 To § 95.050) — Operating a vessel.

For purposes of this part, an individual is considered to be operating a vessel when:

(a) The individual has an essential role in the operation of a recreational vessel underway, including but not limited to navigation of the vessel or control of the vessel's propulsion system.

(b) The individual is a crewmember (including an officer), pilot, or watchstander not a regular member of the crew, of a vessel other than a recreational vessel.