Originally Posted by rbrasi
So, if at 25' LWL, my hull speed calculates to 6.7 Kt. What is the best measure? I currently use a Garmin GPS
to get my speed readings, but that is speed over land. How does that translate? I routinely exceed 6.7 with current and a decent wind, according to my Garmin
is giving your speed over ground. Hull speed is your theoretical maximum speed through the water. If we are doing 6.9 knots (hull speed for the Hunter 29) through the water, but the water itself if moving with say, 1 knot of current in the direction we are travelling, then the GPS
would measure 7.9 knots of speed over ground. Current can help you go faster than hull speed and so can waves. As you slide down the face of the wave, your boat speed will increase. I once clocked 12 knots of SOG while surfing down 5-6' waves and my boat has a theoretical hull speed of 7.4 knots.