What Are the Coast Guard Alcohol Limits for Vessel Operators?

The Coast Guard sets federal standards for operating a vessel under the influence of alcohol or a dangerous drug in 33 CFR part 95. The rules apply to recreational boaters and to crews on commercial vessels, with different alcohol levels for each. They work alongside the chemical testing program for credentialed mariners described in USCG crewmember drug testing.

Who is operating a vessel. On a recreational vessel underway, an individual is operating the vessel if that person has an essential role in its operation, including navigation of the vessel or control of the propulsion system. On any other vessel, a crewmember (including an officer), a pilot, or a watchstander who is not a regular member of the crew is considered to be operating the vessel (33 CFR 95.015).

The alcohol limits. Under 33 CFR 95.020, an individual is under the influence when operating a recreational vessel with a blood alcohol concentration of .08 percent or more, or when operating a vessel other than a recreational vessel with an alcohol concentration of .04 percent or more. An individual operating any vessel is also under the influence when the effect of the intoxicant is apparent by observation of manner, disposition, speech, muscular movement, general appearance or behavior.

State limits for recreational boaters. Where a state statute sets a blood alcohol level for operating a vessel under the influence, that level applies to recreational vessels on waters within the state instead of the federal .08 standard (33 CFR 95.025). Part 95 does not pre-empt state enforcement of state laws on recreational boating under the influence (33 CFR 95.001(a)).

Evidence. Acceptable evidence includes personal observation of the individual's behavior and appearance, or a chemical test (33 CFR 95.030). Section 95.010 defines alcohol concentration as grams of alcohol per 100 milliliters of blood or per 210 liters of breath.

Who may direct a test. Only a law enforcement officer or a marine employer may direct an operator to take a chemical test, and only with reasonable cause. Reasonable cause exists when the individual was directly involved in a marine casualty or is suspected of violating the alcohol standards (33 CFR 95.035). A refusal directed by a law enforcement officer is admissible and creates a presumption of being under the influence (33 CFR 95.040). For serious marine incidents, see USCG serious marine incident testing.

Employer rules can be stricter. Nothing in part 95 limits a marine employer's authority to limit or prohibit the use or possession of alcohol on board a vessel (33 CFR 95.001(b)). The FAQ on marine employer duties for an intoxicated crewmember covers what the employer must do on board. The statutory authority for these standards is 46 U.S.C. 2302.