Ultrasonic wind sensor [CV7]

[Pete O Static]

OMG, this thread is far too complicated than need be.


A GPS displaying COG will tell you your approximate leeway and a waypoint to windward in the general direction you wish to go will give you VMG for your upwind performance on any given tack.



I haven't flown with an E6B or CR2 in over 30 years and I certainly don't want to sail with either of them.


So back to the ultrasonic wind indicator. Do people who have them generally like them? I like the concept of no moving parts.

[a64pilot]

I believe the early ones had a high failure rate from water intrusion.
So far mine has survived Irma etc and is about a yr old. It does seem to be more accurate, no lag for gusts and doesn’t seem as effected to rolling as the manual one did. Either my old wind indicator was way off, or this one is. This one indicates wind speed that seems higher than the old one. I used to could count on being able to easily make 50% of wind speed on a beam reach pretty much, no longer. Finally got a photo of how mine is mounted for who asked

[ronstory]

A64--

That's an Airmar on the pole mount correct?

[a64pilot]

No, it’s a maretron, and the pole could have been much shorter.

[Dockhead]

Originally Posted by a64pilot

No, it’s a maretron, and the pole could have been much shorter.

Why do you say shorter? Looks good to me. It needs to be especially high up if it's not out forward of the mast, to have a chance of avoiding updraft from the jib when going upwind.

My setup is just like yours; my pole is 1.5 meters high.

[Dockhead]

Originally Posted by Pete O Static

OMG, this thread is far too complicated than need be.


A GPS displaying COG will tell you your approximate leeway and a waypoint to windward in the general direction you wish to go will give you VMG for your upwind performance on any given tack.. .

That will work pretty well on a lake.

But at sea -- any tide running will completely invalidate data produced that way.

[a64pilot]

Originally Posted by Dockhead

Why do you say shorter? Looks good to me. It needs to be especially high up if it's not out forward of the mast, to have a chance of avoiding updraft from the jib when going upwind.

My setup is just like yours; my pole is 1.5 meters high.

I hadn’t thought about wind spilling from the jib, I was thinking from being blanked from the Tri-color, and air draft.

[Dockhead]

Originally Posted by a64pilot

I hadn’t thought about wind spilling from the jib, I was thinking from being blanked from the Tri-color, and air draft.

Think three dimensions!

That's why racers have those very long arms for their wind instruments. There's a big updraft from the jib when you go upwind, which will play havoc with your wind data just when you need it most.

[BigBeakie]

We're getting a Maretron WS100, so how far out forward and up is the ideal?


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[a64pilot]

Originally Posted by Dockhead

Think three dimensions!

That's why racers have those very long arms for their wind instruments. There's a big updraft from the jib when you go upwind, which will play havoc with your wind data just when you need it most.

As soon as I read it, I understood. Maybe we should put winglets at the tops of our jibs
Just I had never thought about it is all.

[a64pilot]

Originally Posted by BigBeakie

We're getting a Maretron WS100, so how far out forward and up is the ideal?


Sent from my iPad using Cruisers Sailing Forum

Coming from a guy who had never even considered the issue before.
I believe forward would be more effective, the flow or vortices should spill out of the jib pretty much along the same axis as its leading edge?

That is a question guys, but it is what I think.

[ronstory]

The LCJ Capteurs folks have two physical configs recommended for sailboats. The first is the original CV7 (which I have) and has sensor mounted on wand angled forward of mast about a foot. This is similar to the mounting position of a lot of the traditional whirly cup/vanes systems.

CV7 - LCJ Capteurs

They also have "high speed" version CV7-C with doubles the update rate from the sensor and mounts it vertically on a tall pole to help get clear air for measurement. I didn't by that one because i didn't like the idea of having the unit and it's wires less than a foot from the VHF antenna, at least on my masthead.

CV7-C is the high speed ultrasonic wind sensor. - LCJ Capteurs

Some day I'll have to observe any diffs of measurement when on a beat and what the telltales say. I'm not sure I can compare to windex since that's at worse place at the aft of the masthead.