gps

For sale is a nice Garmin ForeRunner 201. This GPS will measure your max speed during a run if you can find a place to stick it in your boat. This piece is waterproof BUT I would suggest strapping a piece of foam in the wrist strap to keep it floating should it pop out. This piece looks like...

I am sure people are using some sort of Mini GPS devices to measure speed and track of their boats. What have you found, how do they work, are they reasonable, self contained battery, waterproof, etc? Lets see what people have found that work for our application.