Binman
Well-Known Member
What are the laid down wind expectations, for F4 upwards to F8
Wind speed at F4 etc
- Thread starter Binman
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NealB
Well-Known Member
RichardS
N/A
All you really need to remember of that F6 is traditionally called a Yachtsmans' Gale.
Richard
C08
Well-Known Member
But the Beaufort scale does not really deal with gusts eg a force 4 gusting 30 knots is quite different to a non gusting force 4!
oldharry
Well-Known Member
Most people quote the gust speed rather than the average or mean wind speed. Sounds better round the bar too! More detailed forecasts include expected gust speeds. Gust speeds are not easy to anticipate and forecast because they can be very dependent on local topography.
Leighb
Well-Known Member
I thought the standard weather forecast view regarding gusts is that for any predicted wind strength e.g. F4 gusts can be expected up to 50% greater. So max F4 is 16kts, max gust may be 24kts, etc.
Rivers & creeks
Well-Known Member
The basic expected windspeed is important because it determines sea state - a f4 will naturally gust f5 etc but in general the sea state will follow the basic wind force, amplified or mollified by local conditions and tides.
macd
Well-Known Member
That may be so in general, but more accurate predictions of relative gust strengths are available. Gustiness varies from an additional few percent to a doubling or even more of mean wind speed. (Incidentally, a 'gust' lasting more than 30 seconds stops being a gust...not that you're thus justified in ignoring it
) Gusts are essentially a product of vertical instability in the atmosphere. In the UK such conditions are commonly to be expected after the passage of a cold front. Rapid convectional acitivity, such as with thunderstorms, also gives gusts, as we'll all be well aware. As oldharry observed, topgraphical factors also play an important part near land.
If I may harp on about training again; this is one of the many basic essentials one learns when taking a shore-based theory course. At the very least I would recommend the purchase of a sailing manual, Tom Cunliffe's and Bob Bond's are excellent.
Binman
Well-Known Member
In Wikipedia I found just what I needed, the Beaufort scale,that answered my question, will print this off, very useful.
shaunksb
Well-Known Member
That thing on Wiki is very useful, particularly how it shows the relationship the scale has on leaves, twigs and branches to give a visual representation.
Next year I'm going to plant a tree in the anchor well...
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johnalison
Well-Known Member
I find that my limit has come when I see a well conditioned man-o-war reduced to carrying single-reefed topsails and top-gallants.
Binman
Well-Known Member
I do have manuals,it was a spur of the moment thought,that reply made me chuckle shrunksb.
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Daydream believer
Well-Known Member
If you have a copy of "Reeds" you will find it there .
No criticism meant,( thread drift really) but questions are often asked about things which are readily available in Reeds. ( although it is more fun asking on the forum just to see the wide range of mad theories that come up)
It makes me wonder how many people actually use Reeds. I would never go to sea without the current copy.
There is so info much in there that one might have forgotten ,or needs to check. No need to buy a "Tom Cunliffe" or any other book for that matter.
For instance I can never remember when Thames or Dover are due to transmit weather info or the IPTS for ,call before entry ,& just, enter ,even though I have been "foreign" many times. So I have loads of little tabs attached to all the pages I may need for quick reference.
ShinyShoe
Well-Known Member
You may also find these more modern interpretations useful:
http://weather.mailasail.com/Franks...ontemporay-Versions-Of-Beaufort-Scales#dinghy
http://weather.mailasail.com/Franks...ontemporay-Versions-Of-Beaufort-Scales#dinghy
KellysEye
Well-Known Member
>But the Beaufort scale does not really deal with gusts eg a force 4 gusting 30 knots is quite different to a non gusting force 4!
NOAA forecasts point out that gusts can be up to 40% of wind speed, having been long distance sailing I know it's true. For example over Biscay we had 35 knots gusting 50, a ketch ran off towing drogues, a cat hove to using both engines and sadly a local fishing boat was lost with all hands. We had a heavy displacement long keel with cutaway forefoot steel ketch and kept sailing.
NOAA forecasts point out that gusts can be up to 40% of wind speed, having been long distance sailing I know it's true. For example over Biscay we had 35 knots gusting 50, a ketch ran off towing drogues, a cat hove to using both engines and sadly a local fishing boat was lost with all hands. We had a heavy displacement long keel with cutaway forefoot steel ketch and kept sailing.
nigelmercier
RIP
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While I don't disagree with your post, I have never found any need to use the Beaufort Scale. Perhaps because I have a wind speed instrument that tells me the actual speed.
macd
Well-Known Member
Your wind speed instrument can predict future winds? Where can I buy one?
Seriously, if a forecast describes wind in Beaufort terrms, and many do, surely it's useful to be able to understand it?
nigelmercier
RIP
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- Live in Kent, boat in Canary Islands
I guess the location of my boat is also a factor, I have never listened to the shipping forecast while on board.
macd
Well-Known Member
It's not just the Shipping Forecast. The Meteo Greece forecasts (both sea area and land locale) for where I am now has wind in km/hr and Beaufort. km/h is pretty meaningless to me in terms of sailing conditions. Beaufort I understand.
