Originally Posted by Troubadour52993
The ST60 only gets boat speed info from the speed paddlewheel if you have a triducer in the water. If the paddlewheel is out, or you don't have a triducer, the ST60 will read true and apparent as the same.
FWIW, I did the "calibration" to try and make the SPEED match SOG from the GPS, but it's still off a bit, especially when speed is a few knots different from where I set the "calibration constant". At least to my knowledge, there is no way to get the ST60 wind to use the GPS SOG on seatalk as the boat speed input. I wish there were, as I trust it more than SPEED. Ditto for Trip Log.
This is a problem with the ST60 series. At this price
point they should allow the option of input of SOG from the GPS. It would be a simple software
There is some debate about which is the most useful "true wind" derived from SOG or STW. I feel SOG is more useful for cruising yachts, but others disagree.
For "true wind" derived from STW the log needs to be accurate which in my experience is not found on cruising boats. The true wind varies, even in non tidal waters, with the tack and point of sail, making the data useless.
Try the same with "true wind" derived from SOG via the GPS and the data is rock solid and accurate.
"True wind is very useful, but if you have to make allowances for port and starboard tack or how many days since you last cleaned the paddlewheel the information is meaningless. Get a system that uses the GPS input and you will learn the value of accurate "true wind"