Wind System on a Mac

[c130king]

If the wind vane is on/near the arch wouldn't the wind coming off the sails affect the accuracy? Just curious.

Jim

[Night Sailor]

Since I haven't tried it, I agree the wind coming off the main could possibly cause deflection or false speed readings in a position too close to the boom end, for example the bimini.
My thinking is that on a Mac, there's a good six or seven feet from boom end to arch or pole postion at the stern if they are angled over the motor as mine is, so it would negiible. I could be wrong, but it would be easy enough to try it in a temporary mount to see, before gong to the trouble of mounting on the mast and running cable inboard.

[bastonjock]

my own view is that the wind vane should be at the top of the mast especially if you are interphasing it with the Auto Pilot.I will fix my wind vane and VHF aerial to the mast top,i like the idea of having 15-20 miles of radio contact nad an unobstructed vane for wind measurement.The downside is having to protect the cups,the aerial is not so badly effected,Even if you do not break the cups on the wind vane,travelling at 65mph for a distance will not do them any good,so i wrap them up,i push the mast forward beyond the bow,then wrap the cups before i fix it to its trailering position.

[Matt19020]

2BonC,
In that picture I left it on...typically I remove it and bag the end of mast. I am only 3 miles from my marina. I broke my ankle at the end of last season and I did minimal prep to get the boat home.
I did not connect to autopilot because of the rotating mast, It would not give an accurate wind direction unless you mounted it on the arch like Delevi. I use my Davis Windex for that.
The autopilot has a built in tack feature regardless of wind information. It will spin the boat 100 degrees (user adjustable).
I tried it and it worked pretty good.
Sloppy video of autotack feature without any fine tuning... no hands touched the wheel for video- http://www.youtube.com/watch?v=0GizEICFi4g

[delevi]

Matt,
By not hooking up the AP, you're missing out on windvane mode. It's a great feature allowing the pilot to track to a specific wind angle vs. a waypoint or (point & shoot.) Great way to take a break from trimming or if you just want to sail really close to the wind (with computer precision.)

I don't believe the mainsail has much affect if any. The post I'm using is 6 feet high so it's pretty much out of the way of airflow. Readings seem to be consistant with sails up or down.

[Clemo]

I have Nexus brand instruments on my X (Wind, Log & Depth). The mast head unit is wireless with its own PE cell, so no cables. One nut removes it from mast and it travels/rests inside the boat under the window (to keep the battery charged.)

At the time there was a marked difference in price between Nexus and Tac-tic.

As for use, I put the least experienced person on the helm, explain where I want the apparent wind on the dial and let them go. To easy!

I have seen a mod to measure and correct for mast rotation on an M. Glad I was fitting to an X.

Tks
C ya.

[PatrickS]

I'm old fashioned I guess. I've seen the need for one on big or little boats I've skippered. Then again, maybe it's a racer thing, and I'm a cruiser.
I don't have one on my X for I don't really see a need for one because my little handheld will confirm windspeed enough for me to record it in the log if it's significant or unsual.
If I did want one I would not mount at the top of the mast. I would mount it on my arch or a separate pole that is easily taken down for transport, maintenance or repair. The majority of a sail's surface is near the hull, closest to where you helm, closest to where it will react with the sea. It somehow makes more sense to me to know what is happening in my environment, not 30 ft overhead where the least effecient part of the sail is located.
A simple wind vane or a ribbon telltale at the top of the mast is enough to see upper level wind shifts near capes, bridges, etc.

For me, the ST40 is primarily part of the autopilot, so that it will keep the boat at a particular angle to the wind, if the wind shifts (safety).

[Matt19020]

Delevi,
I agree but I already wired the wind monitor two years ago. I may get around to relocating it to your location, but for now I just want to sail and not do any more mods It has been a long winter with my bad hoof....

[mike]

This is what I used...

http://www.defender.com/product.jsp?pat ... &id=680929

Our boat had one of these already when we got it... the previous owner (or the dealer) installed it for the anchor light and foredeck/steaming light, so I added another for the wind instrument (IIRC, the wind instrument had 4 conductors). Anyway, it works great, and looks clean too.

--Michael