Alcohol has many physical effects that directly threaten safety and well-being on the water.
When a boater or passenger drinks, the following occur:
Cognitive abilities and judgment deteriorate, making it harder to process information, assess situations, and make good choices.
Physical performance is impaired - evidenced by balance problems, lack of coordination, and increased reaction time.
Vision is affected, including decreased peripheral vision, reduced depth perception, decreased night vision, poor focus, and difficulty in distinguishing colors (particularly red and green).
Inner ear disturbances can make it impossible for a person who falls into the water to distinguish up from down.
Alcohol creates a physical sensation of warmth - which may prevent a person in cold water from getting out before hypothermia sets in.
As a result of these factors, a boat operator with a blood alcohol concentration above .10 percent is estimated to be more than 10 times as likely to die in a boating accident than an operator with zero blood alcohol concentration. Passengers are also at greatly increased risk for injury and death - especially if they are also using alcohol.