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billgfc
Joined: 20 Aug 2006 Posts: 226
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Posted: Wed Oct 13, 2010 10:23 am Post subject: Rooster rock Lite wind meter |
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that meter may be the most accurate of all as for what the water is doing! 40 s gusting over 50 today
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hilton08
Joined: 02 Apr 2000 Posts: 505
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Posted: Wed Oct 13, 2010 10:31 am Post subject: Rooster Cam |
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Looks really windy!
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http://www.pdxgreen.com/RoosterCam.aspx |
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bobgatpdx1
Joined: 13 Oct 2002 Posts: 385
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Posted: Wed Oct 13, 2010 7:25 pm Post subject: |
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Was a windy one today! I didn't get a chance to sail today, but it looked like solid 3.3m conditions. Yesterday it was reading mid-30's and I was pretty wound up on my 3.7m.
I've decided the "calibration factor" is:
Rooster_sensor - 6mph = Swell_City_sensor units.
Can't wait to see what it looks like in January!
BobG
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andymc4610
Joined: 19 May 2000 Posts: 684
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Posted: Wed Oct 13, 2010 7:36 pm Post subject: |
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always wondered how this sensor would compare....would have, should have, could have gone today.
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husby_d
Joined: 10 Sep 2000 Posts: 16
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Posted: Thu Oct 14, 2010 5:33 pm Post subject: |
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I wonder if the Rooster sensor is sending in KPH instead of MPH.
Was out on Tuesday. The sensor said 30+ gusting to 40+.
I was on a 4.2 + 75L, and the gusts seemed to be at most in upper 20s.
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bobgatpdx1
Joined: 13 Oct 2002 Posts: 385
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Posted: Thu Oct 14, 2010 10:26 pm Post subject: |
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The Rooster sensor is reading MPH.
It is mounted on top of the big tripod in the river ("66") about 40ft above the river so it reads a bit high. I've been subtracting 6MPH from the sensor reading for figuring out what sail to use.
I also sailed Rooster on Tues (10/12/10) from 12pm to 3pm.
Sensor said 36MPH at the start and 31MPH at the end.
I was on my 3.7m/84L and was a bit overpowered at the start and slogging some at the end.
BobG
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billgfc
Joined: 20 Aug 2006 Posts: 226
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Posted: Fri Oct 15, 2010 1:35 pm Post subject: |
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Hi Bob
Did you use a wind meter to compare actual to sensor?
I have taken a few wind measurements over the years in that area. i might comment you can use a larger sail in east wind than in west. there is less drive as you may be going from say 3 or 4 mph current with wind in same direction to same with wind opposite.. thats a big pressure change and rougher chop.
What do you think?
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bobgatpdx1
Joined: 13 Oct 2002 Posts: 385
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Posted: Fri Oct 15, 2010 10:42 pm Post subject: |
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I haven't tried the handheld wind meter yet. Will try that next time.
I agree that you have to apply an "east wind factor" to account for the difference in the current.
I use the Swell City sensor (west wind) as my reference, since I mostly sail at the Hatchery. I know from experience that at the Hatch I can use these sails vs AVG windspeed:
>= 15MPH : 5.7m
>= 17MPH : 5.2m
>= 19MPH : 4.7m
>= 22MPH : 4.2m
>= 25MPH : 3.7m
>= 30MPH : 3.2m
At Stevenson, I apply these correction factors to the sensor speed:
For west wind: Stevenson - 2MPH = Swell
For east wind: Stevenson - 4MPH = Swell
For Rooster, I've been using this correction factor:
Rooster - 6MPH = Swell
I find that Maryhill & Dougs are pretty close to Swell (no correction factor).
All of these are approximate of course, still have to look at the situation and if possible ask others what they are sailing. If the wind range is really wide (big lulls or big gusts or both), then this also changes the sail selection. However, the above rules-of-thumb give me a starting point.
BobG
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billgfc
Joined: 20 Aug 2006 Posts: 226
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Posted: Sat Oct 16, 2010 1:16 pm Post subject: |
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Hi
I am amazed at the super tight tolerances on the sails, but there is likely a rough relativity factor of wind sensor (a rough constant) to what is actually going on where you sail.
So you use the sensors at all these sites to evaluate what you sail and where.
the sensors here again, wind direction aside are relative constants
This appear the foundation for predictability on what you choose and enjoy.
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billgfc
Joined: 20 Aug 2006 Posts: 226
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Posted: Thu Nov 11, 2010 3:33 pm Post subject: |
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I would add a great place to test product for mfrs and for fun!
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