I am curious as to how accurate this is at determining your max sailing speed. My hull speed from the manufacturers states 6.5 knots...I can get to that pretty easily, I would have thought that it wouldn't be that easy to get to the max speed. This was actually close hauled into the wind...I know you can get way above that downwind and surfing the waves. This speed was from my GPS and that was averaged over 3 minutes so it wasn't just a spike at that 6.5 speed...it was an averaged speed. With some tweaks to sail trim and a very clean bottom I'd think I can get to 7.5. Where some manufacturers more conservative with rating the hull seed? Or is it maybe modern sails and rigging make it actually possible to sail above hull speed? Or am I thinking too much and just enjoy that I can get the boat moving like that!
As others have said, you need a knot meter. If there is current where you sail it will effect how fast you are going through the water.