Don't beat yourself up too much. You faced somewhat of a dilema. If you felt you must act, maybe the best time and place might have been before the departure of the booze cruise and on the dock. The authority to notify in that case would probably have been the police and not the coast gaurd. The dilema, as I see it, is this; you are worried about the safety of these people because you are obviously a compassionate person, but being so you don't neccessarily want to "rat out " a group of young sailors to the cops for drinking beer and messing around in boats (hell, half of the boating fraternity could be led away in handcuffs for that). Maybe a discrete request to the local coast gaurd unit to walk down the dock before departure and do a "routine" safety inspection on the vessel was in order. Anyway, I think that your concern is refreshing.