The effect of alcohol is increased by the natural stressors placed on your body while boating. Also, alcohol causes dehydration of your body. It takes less alcohol, combined with stressors, to impair an operator's ability to operate safely. Research has proven that one-third of the amount of alcohol that it takes to make a person legally intoxicated on land can make a boater equally intoxicated on the water.
Alcohol depresses the central nervous system, affects judgment, and slows physical reaction time. Most people become impaired after only one drink.
Alcohol makes it difficult for you to pay attention and perform multiple tasks. For example, it will be more difficult for you to keep track of two or more boats operating in your area. This could become critical if you are placed in an emergency situation and must make a sudden decision.
Alcohol can reduce your ability to distinguish colours, especially red and green.