RupertW
Well-known member
I'm talking about my R/C sailing boat which never gets further than the village duck pond.
It's still confusing though because most of the wind is duck fart.
Richard
Love it
I'm talking about my R/C sailing boat which never gets further than the village duck pond.
It's still confusing though because most of the wind is duck fart.
Richard
If your instruments call it True Wind, or TWS/TWA, then it is calculated using the speed through the water and the heading. That is the industry standard.
The industry standard is that wind calculated using GPS data is called ground wind.
Not sure what the issue is here?
My trouble is that I can't imagine myself while on passage asking my crew for a report on the "meteorological true wind" or "industry standard wind". Life isn't like that, and we need simple terms for simple sailors. Many of the forum members have drifted fairly easily into using True wind and Ground wind for normal use on sailing craft, and whatever the rights and wrongs, usage will always prevail.I hope that sailing schools spend a bit of time talking about the differences between Meteorological True Wind and Industry Standard True Wind - it certainly wasn't covered when I did Yachtmaster at the same time as my wife did Competent Crew, and a couple doing Day Skipper helped during my exam.
If an instrument for measuring the speed and direction of the wind is mounted on shore, then the readings obtained are those of the speed and direction of the true wind.
Many of the forum members have drifted fairly easily into using True wind and Ground wind for normal use on sailing craft, and whatever the rights and wrongs, usage will always prevail.
So the industry standard means that the true wind for a boat in a faster flowing current in the middle of a river is different to the true wind for a boat half a mile away in the slower flowing current, (or back eddy), at the edge of the river?
Yes, the met office will (obviously) predict the Ground wind. But then they just call it "wind".Presumably, there is also a "Meteorological true wind" which is the same as the industry standard "ground wind"? In which case there can be two ways of defining true wind, hence the question in the OP, and neither is wrong.
I hope that sailing schools spend a bit of time talking about the differences between Meteorological True Wind and Industry Standard True Wind - it certainly wasn't covered when I did Yachtmaster at the same time as my wife did Competent Crew, and a couple doing Day Skipper helped during my exam.
No, tied up at the dock we feel the ground wind.
Drifting with the tide we feel the true wind.
Sailing along we feel the apparent wind.
Remember, the only wind we can measure is the apparent wind. Everything else we display is a calculated field.
Yes exactly. It would be a nonsense for it to be anything else.
Then that true wind would vary depending on the quality of the measurements which isn't right. The true wind should be independent of your instruments, it's the same regardless of the equipment used. The variation is in your measurement of it, not the wind itself.
The log is especially tricky as it presumes the boat to be moving forwards through the water, when it doesn't.
Just did a quick google and am amused to find that inconsistent application of definitions is a problem that goes beyond BW posters:
https://support.garmin.com/faqSearch/en-US/faq/content/lQFTLBSlv73TYGsOpDB7P6
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After all, judging from the poll results about 50% of YBW members think their instruments are displaying ground wind when the true wind option is selected.
At no time during my time have I ever heard, or considered, that True Wind is anything other than the wind over the ground. I don't think I have ever considered anything described by instruments as true wind as the "real" true wind, knowing instinctively that there is an unknown component missing. I have never thought along the lines of an industry standard, or even been aware of it.
Just did a quick google and am amused to find that inconsistent application of definitions is a problem that goes beyond BW posters:
If an instrument for measuring the speed and direction of the wind is mounted on shore, then the readings obtained are those of the speed and direction of the true wind.
https://support.garmin.com/faqSearch/en-US/faq/content/lQFTLBSlv73TYGsOpDB7P6
Why is this inconsistent? All it says is Ground Wind = True wind if the sensor is not subject to tides/current/movement etc.
The IMO's view is
"True wind speed and direction means wind speed and direction which are not reflected by ship’s speed and heading.
Relative wind speed and direction means wind speed and direction which are reflected by ship’s speed and heading."
Nothing about any other type of wind or measuring over ground, sea, currents, tides.
In my view it would be the true wind speed and direction measured over a fixed position on the earth's surface. i.e ground as the wind speed and direct is not by ship’s speed and heading.
... tied up at the dock we feel the ground wind.
Drifting with the tide we feel the true wind.
Sailing along we feel the apparent wind.
I'm wondering what name those who have chosen "relative to fixed point attached to the Earth" would use for the other wind? (Presently a majority of respondents, which I find slightly surprising incidentally)
I also have to say I'm deeply cynical about all the reasons for needing a "wind with tide effect factored in/out" number apart from the polars one and I'm a little bit cynical about that because I don't trust the kit that makes the measurements of heading, speed through water and wind speed to be accurate. I think on most boats if you significantly change course with 'True Wind' showing on instruments you see that 'True Wind' suspiciously change value which suggests to me the inputs are wrong.