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chala · 22-11-2009, 07:45

Why is it that 99% of the wind vane transducers I have seen are fitted forward of the masthead, facing an undisturbed flow of air where it is not possible to sail and in an other hand receiving a flow of air disturbed by navigations lights and other items when sailing down wind?

delmarrey · 22-11-2009, 11:12

Sailing before the wind, a wind instrument will only measure the wind that gets past the vessel, which should be very little. Besides your sails should tell you from which direction the wind is coming, otherwise your sails will be thrashing around unfilled in which one would have little time to even view his instrument.

chala · 23-11-2009, 19:17

It is an accurate wind direction that is of importance to a helmsman or an autopilot, not so much the speed of the wind.

**Pblais** · 23-11-2009, 19:35

Quote:

Why is it that 99% of the wind vane transducers I have seen are fitted forward of the masthead

On some boats they can't install the vane forward and have to install it backward. I have a boat that had it both ways and can't say it really matters in spite of most people doing it forward. It seems the better idea in any case.

They won't disqualify you for it. You need a place that can support the installation on the top of the mast head. I suppose you could do it sideways and calibrate it just fine too. The vortex from the mast will have an effect. If it really matters you'll never know.

chala · 03-12-2009, 20:25

I would have thought that this type of obstruction on the front of the autopilot wind vane would have the same effect on the course keeping ability of the autopilot as the dangling of a steel can near the autopilot fluxgate compass.

**Pblais** · 04-12-2009, 06:09

Quote:

I would have thought that this type of obstruction on the front of the autopilot wind vane would have the same effect on the course keeping ability of the autopilot as the dangling of a steel can near the autopilot fluxgate compass.

It's not clear to me what you are talking about.

**GordMay** · 04-12-2009, 06:29

Quote:

Originally Posted by Pblais

It's not clear to me what you are talking about.

Quote:

Originally Posted by chala

I would have thought that this type of obstruction on the front of the autopilot wind vane would have the same effect on the course keeping ability of the autopilot as the dangling of a steel can near the autopilot fluxgate compass.

I suspect ...

A steel can (or any other magnetic material), placed in close proximity to a compass, will cause magnetic disturbances , resulting in compass error.

Likewise, installing anything in the airstream of a wind vane will cause aerodynamic anomalies, resulting in vane error.