Join Date: Dec 2004
Location: Alameda, San Francisco Bay
Thanked 56 Times in 55 Posts
Rep Power: 11
Re: Any Ideas
I am usually a bit skeptical when I see max speed readings off of a GPS. You can introduce an error by either having the sampling rate set too fast (a lot of factory settings have this at a second or less) and/or having the antenna mounted far from the center of motion. So, if the antenna sways and the sample rate is fast, the relative motion of the antenna is added to the speed of the boat. When I was campaigning my boat I wanted to measure the acceleration out of tacks so I set the sampling speed really fast which made the max speed pretty useless but did give me some pretty good data I could analyze on the computer. Normally, I set the GPS to sample at 30 second intervals. That said, I think that Travelin Easy’s over-all speed was pretty fair- averaging 5.6 knots over four hours nets out to running at 80% of hull speed for a good portion of a day.