A power boat is very bad for the environment.

They waste a lot of gas and oil.

They drip pollution into the water.

Also according to this article and new laws the fumers are 200 times more deadly than a car or truck,

Bill would target poisonings tied to boat exhaust

Matthew Benson
The Arizona Republic
Jan. 9, 2008 12:00 AM

I was amazed to read recently that we drip and leak more oil than the Exxon Valdez lost when it went aground. How is your area ?
Here's one reference-
http://mass.gov/dep/images/oilspi01.pdf
One quart of motor oil can pollute 250,000 gallons of water, and one gallon of gasoline can pollute 750,000 gallons of water! Oil that leaks from our cars onto roads and driveways is washed into storm drains, and then usually flows directly into a lake or stream.