anemometer^

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phonefro
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Joined: Thu Nov 19, 2015 8:49 am

anemometer^

Post by phonefro » Thu Nov 19, 2015 9:03 am

Hi, all. I'm new member here. thanks for this site.

I want to buy a anemometer for fishing or sailing, if can put in pocket of backpack may be better. This one seems good of price http://amzn.to/1R6xw0e Any suggestions? Can anyone tell me whether this is able to measure wind direction? Thanks

MikeVeal
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Re: anemometer

Post by MikeVeal » Fri Nov 20, 2015 1:33 pm

I use one of these for paragliding:
http://www.seamarknunn.com/acatalog/xpl ... k8g1DK-PG4

You need to line them up with the wind to get a true reading. So, no, they don't measure direction. For that you need a handfull of grass and a compass.

geoffm
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Re: anemometer

Post by geoffm » Fri Nov 20, 2015 6:33 pm

I use one of the US Kestrel meters that are tested laboratory accurate. http://kestrelmeters.com/products/kestr ... ther-meter I also have a Skywatch as referred to. The Kestrel is significantly nicer to use.
Geoff

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Jim
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Re: anemometer

Post by Jim » Mon Nov 23, 2015 11:12 am

Anemometer only measures wind speed, a weather vane will give you direction.

I would be wary of most of the cheap anemometers which us a propeller on a horizontal spindle, because you need to turn the meter to face into the wind to get an accurate reading from it (although for most uses a bit of error is no probem), although at least doing this means you will be forced to find the wind direction for yourself.

I use the type with cups mounted on a vertical spindle, because they give a good reading of wind speed no matter how you hold the meter to the wind (keeping the vertical axis vertical is a good idea) - Keindl Wintronic II, but I don't think it is made any more.

As for measuring wind direction, what are you looking for in that respect?
Just a visual indicator of wind direction, or something that can tell you a compass bearing for the wind direction?
For a visual indicator a burgee, or weather vane or windsock all work adequately well. If you want the compass direction, you will either need to set up a base to a given direction to read off, or perhaps find something with built in electronic compass that can work it out for itself.

For sailing there are still more complications with direction. When you are moving (under any power source) you create another wind vector, which when added to the true wind vector creates an apparent wind, which comes from slightly more ahead of you than the true wind. In most scenarios you probably don't much care which you are measuring, is sailing however it is often more useful to track the apparent wind direction that the true wind, as the apparent wind is the wind that the sail operates in. To complicate things further, wind is slower closer to the ground, and as it slows the direction changes slightly, so the apparent wind direction at the mast head and at the boom height can be a few degrees different (which is why sails have not been developed with zero twist along their length, the right twist is actually useful to get even loading!) although over the height of a sea kayak rig I don't think this effect is measurable.

To be honest, I have never found an anemometer useful when kayaking - I will be making a judgement based on what I can feel of the wind and see of the water conditions, in conjunction with the forecast which should indicate f it will stay the same, or get worse or better. My reason for having an anemometer is kite buggy racing, where each kite size only really works over a small range of wind speed and guessing the speed is not really accurate enough - simarlaly a yachtsman would use it to work out when it is time to increase or decrease sail, but in a kayak with a single sail it should be quite easy to work out by feel if there is a enough wind for sailing, or too much. Of course there are those, like Douglas, who record every detail of their trips for future reference where having an anemometer enables them to put good wind data in their records - I don't remember seeing him holding it aloft on the water to decide whether or not to try sailing though :)

flat earth sails
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Re: anemometer

Post by flat earth sails » Mon Nov 23, 2015 9:07 pm

Jim, a grate explination , sailors say you cant sail on true wind !
Re sail twist, over a meter or so of sail twised is irelaveny , in the CZ range of sails I encorporated Twist , not to even out wind preshure but to give them a brorder range of sailing conditions the new Tradewind sails have considerably less twist which makes them power up more, more bang per m sqr !
I had an animometer and found it a bit yousles for sailing as it meshured the wind at the rong place and not worth yousing for kayaks if you think its between 5and 10 knots and from over a sholder you shold get sumthing out of it

sunstreaker
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Re: anemometer

Post by sunstreaker » Tue Nov 24, 2015 2:26 pm

Have you seen the phone Apps?
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