I agree that you can get an inaccurate max speed reading at times with a GPS, but overall I think they are very accurate. My favorite use is to download the tracks after sailing to see where I had been. (ExpertGPS software) Here's a track from last Friday morning in Key Largo. The winds got to be a bit much, but thanks to Mary and Ricks help when landing downwind on the beach, I didn't have any repairs to do when I got home.

Jack Hoying
Prindle 18
Fort Loramie, Ohio