Operating a mechanically-powered vessel or sailboat while under the influence of alcohol is a Class A misdemeanor in Tennessee. For the most part, the rules regarding alcohol impairment that apply on the water are the same as those that apply to drivers of motor vehicles. You can be convicted of boating under the influence (BUI) if you are found to have blood alcohol content of .08 or more. The operator of a boat gives implied consent to blood alcohol testing, just as the driver of a car or truck does. The penalties upon conviction for BUI are the same as for DUI. And during certain holiday periods, officers from the Tennessee Wildlife Resource Agency (TWRA) intensify their enforcement efforts, just as state and local police on land do.