I just came in from sailing my Blade with my Garmin ETrex Legend taped to the boom. I had it set for MPH, I didn't realize until after, but it showed 19.3 mph (anyone know what that is in Knots?) was my max speed. I was alone and running deep downwind in some 20 knot gusts with spinnaker pulling bows up, sitting on the tramp running on both hulls, not out on the wire on one hull. I think it might have been trying to plane. I think I have gone faster on the boat but that was all the wind I had to work with.