Rotating Mast.

[Jacaranda]

Will the rotating mast on a affect a nasa wind system ?
Has anyone fitted such a system ?
Was there any problems ?

[Matt19020]

I have the Raymarine ST40- http://www.raymarine.com/ProductDetail. ... RODUCT=425
This works well however the wind direction is not accurate because of when the mast rotates, it changes the baseline measurement of the sensor. I use a Davis Windex for wind direction and the RAymarine ST40 for windspeed. If you keep the mast from rotating or figure a way to mount it forward on a spreader it may work ...but I think that would be counter productive for the benifit you would recieve.

[TAM]

We have our ST40 rotovectra mounted on the mast support arch. Seems to get proper readings in all directions. I was concerned that when to the wind it would be inaccurate. Doesn't seem to be the case. Knowing the wind speed has really improve my sailing as I can tell how well the boat is performing compared to wind. Having fairly accurate direction means not having to look up to the windex. (difficult to see around the bimini)

I also looked at a furumo unit with built in compass (compensates for mast rotation), but it was too expensive compared to the ST40.

[delevi]

I also have the ST40. Not mounted to the masthead due to rotating mast as already stated. Readings are reasonably accurate. It's a great companion to an autopilot, allowing the pilot to lock on to any wind angle and adjust to wind shifts.

[baldbaby2000]

Here's how I did mine. There's a potentiometer in the base of the mast that feeds the mast angle into the system for correction: http://www.macgregorsailors.com/modt/index.php?view=701

Since the mast likely rotates the same angle after a tack, you could probably have two different scales: one for starboard tack, and one for port tack; and read the appropriate one to get your apparent wind. Perhaps these could be transparent overlays on your display.

Dan