MacGregorSailors.com

kurz wrote:here the anwer from sailtimmer:

"Yes, the new SailTimer Wind Instrument™ has a digital compass right on the wind direction arrow, so it works with rotating masts. It doesn't matter if your mast rotates, the wind direction arrow still knows which way it is facing.

The new product does not have a base unit because it can transmit directly to mobile devices. However, there is going to be an accessory box that allows you to receive the wireless signal, and then send the wind data on with a wire using NMEA to your normal chartplotter.

The price of the accessory with the NMEA plug is not known yet."

Sounds goot, however we need practical expoeriance and price info for the whole set incl. wiring box for the plotter.

I looked this unit up. Says they'll pre order sell at $350. If they could offer the whole kit including the interface to chart plotter/auto pilot for under $500, I'm in. Wont be able to report on it until seven months from now tho. Outside temp presently holding at -15c here

kurz wrote:here the anwer from sailtimmer:

"Yes, the new SailTimer Wind Instrument™ has a digital compass right on the wind direction arrow, so it works with rotating masts. It doesn't matter if your mast rotates, the wind direction arrow still knows which way it is facing".

Pennies dropped now, it uses a compass to get the bearing to the wind angle then the heading information to calculate the port/starboard angle. Knew there had to be a additional information to get that angle not just heading . It use a compass as a substitute for a goniometer, clever.

This will still be apparent wind not true, will still need boat speed to calculate true.

kadet wrote: This will still be apparent wind not true, will still need boat speed to calculate true.

Why you need true wind? If you have an autopilot/plotter you can use the sailtimmer and sail always with the saim sailtrimm, but if the wind changes, you will change sailing direction too, I GUESS.
Is this not true?
Why do you need the true wind? I guess a plotter should calculate this out. What signal are they normally using?

kurz wrote:

kadet wrote: This will still be apparent wind not true, will still need boat speed to calculate true.

Why you need true wind? If you have an autopilot/plotter you can use the sailtimmer and sail always with the saim sailtrimm, but if the wind changes, you will change sailing direction too, I GUESS.
Is this not true?
Why do you need the true wind? I guess a plotter should calculate this out. What signal are they normally using?

I don't but previous post referred to this as measuring true wind.

To measure apparent wind, you have to know the boat's heading. Apparent wind includes ship's speed, so you do not need to know it to factor it out.

To measure true wind, you have to know which way is north and you have to know the ship's speed so you can factor out ship's speed. No way around that requirement.

So the one you measure depends on the thing you know in the instrument, and the other one is calculated by your chartplotter based on additional information that it has (heading sensor, compass, and GPS speed, or whatever).

What I can't figure out about the SailTimer instrument is how they could factor apparent wind having only true north and without having the ship's speed. I'll ask what they're doing.

Heres my mast top swivel brkt that allows the mast to still rotate with a back-stay the brkt can be left stationary or the back stay can be moved from port to starboard 0n a arch mounted traveller
http://i235.photobucket.com/albums/ee20 ... 0012-2.jpg

http://i844.photobucket.com/albums/ab1/ ... 010006.jpg

J