Excuse the thread hijack but, basically it's the same as a sailboard sail, except your "arms" are 25m long.
When there's too much wind you push the bar out and edge a bit and the kite depowers and moves to the edge of the window.
If you have a small kite up you can dive it to create power to get up and planing and create apparent wind. You can then move the kite to the middle of the window and harvest all the power there is. It's a little bit like pumping a sail except sail-pumping is hard work and difficult to do effectively. Diving a kite is effortless.
We had gusty winds on Friday between 15 and 30 knots. I had a 7m kite and was well powered and did a long upwind cruise (chasing yachts upwind with a fast downwind return. :-D ). A 7m kite is good from 18-20 knots up to well over 40 knots. Other guys had 12m kites and were doing ok. I would not have recommended the 12m for the day but the guy I saw was doing ok. Using a too big kite is using up your safety margins. The ideal would have been an 9m kite. The sailboards were slogging along in the lulls and comfortably powered in the gusts.
Or you could just watch the 6.00 weather forecasts.
What an absolute crock of smoking dog s**t.....
" and on the bays wind will from the east at 25-30 kilometers per hour"
w.t.f.?? whats wrong with knots? and don't tell me knots per our either.
Even the BOM have many forecasts with wind predictions in Km/h. If you on land, who gives a toss how windy it is? If your going on the bay, then the forecast is important and you will know what a knot is, and what that means in real life.
ie am I going to get smashed or go for the screecher.
rant over.
Good thread anyway.
and by the way, I'd waste $20 for an ebay toy that told me the windstrength.
Who cares if you risk looking like a knob using it, if it gives you a bit of a better guess, go for it.
I agree the BOM are good for forecasts, with the caveat that they tend to overcall things to protect boaties.
Even the best forecast does not tell you what is actually happening though.
Local knowledge can't really be beat though.
My method is:
- if I'm at the beach and it's on I rig up and go out.
- if on the beach I can hear a definite wind noise in my ears (not between my ears) I go out with light wind gear.
- white caps and I rig smaller
- sand blasting and I rig smallest
If I'm at work or at home:
- read the BOM forecast for the bay.
- look at the marine simulation covering the area (to get an indication of the time of day things are going to happen.
- have my gear in the car all the time 
- watch the observations for Fawkner Beacon and Moorabbin airport (Fawkner usually read a tad high for my beach so Moorabbin airport confirms what I hope is happening.
- if both crack 12-13 knots I'm off.
- I check the BOM radar as a safety check to make sure there are no deadly storms around.
- If I am away down the coast I will check the BOM stations on either side of where I am.
If I'm at Sandy Pt and there no wind on the bay but wind in the trees I will drive to Shallow Inlet and have a look, checking windmills on the way. If not I go surfing.
But the terrain affects the wind coming into my sail just as it affects anemometer readings, that's my point. The grunt part is only a couple of meters above the water. Good wind at 10m up is useless to me when I'm stuck in a shorebreak or a big set of waves. If it's 12-13 kts on the water, I'm screwed, 15 kts gives me a fighting chance. That's the distinction I'm using it for.
Where did I say that a hand-held anemometer is a flawless device that will make the wind blow steady and true on all quarters at precisely the speed measured ?
At the end of the day, wind is part of an emergent system, and subject to all sorts of vagaries and changes throughout the day. We all know that.
BOM forecasts typically cover about 300km of coastline each, which is a rough stab at best for any given beach.
Wind in bushfire zones in bushfire season is not really representative of we are dealing with either, so I'm not sure how pertinent that experience might be to this discussion.
Ken. Why would there be good wind at 10 metres but none at the surface? The ratio varies a bit but surely not not by that much on a sunny well-mixed day over the same patch of water. What do the kiters say, they can sample both heights very easily?
Not sure that wind qualifies as an emergent system type of behaviour, it's bad but not that bad, that's more global economy sort of unpredicability.
Water turbulence affects wind fetch badly. The rising and falling peaks and troughs mess up the flow big time. Contrast that to say, Sandy Point where there is an open fetch with wind coming of a solid sand-bank. Ther eis no disturbance to the flow there, and the wind can really get itself organised. The results prove that.
Get stuck in the trough of a big set of waves and there is no wind. You can feel the dramatic difference as you rise up onto the crest of a swell. You get the same compression effect as a dune or hill gives. So a steady 12kts at 10m up feels like 6 in the trough and 16-17 on the crest.
Places like Elliott Hds where you get a ton of tall wind chop right in the river mouth, especially on a wind against tide, suffer a lot. It an be a solid 30kt howler, and there will be dead spots that nearly kill you.
It's not always a sunny well-mixed day and I'm not really a flat water, large gear sailor either.
Sure, those conditions are easy to call, and I'm not saying that me or anyone else can never estimate wind right.
It's more that some conditions can be difficult to gauge accurately, and then it's nice to have an objective measure to help.
All weather systems are emergent. That is, while there it is possible to define the set of rules that make it function, there is such a high level of complexity that you have to run the system to see what will actually happen.
More than 3 days out and it becomes chaotic.
Which is why 7 day forecasts are rarely if ever on the money.
This aint a site for a degree in meteorology! Jeez just check out the conditions -sand moving? - trees moving? - whitecaps? - what are other guys using? - unless this is your first time out you must have some idea, never seen good sailors standing around like knobs studying wind speeds. They leave that to the posers, you know the sort of guys who sail the Swan river with all the latest expensive gear and never leave the learners pool in case people can't see them, wind meters are right up their alley along with a GPS which tells them they have just done 10 knots!
