Like all good fishing stories...
there is a bit of truth in all...
everything is relative...
agree, this video is not example of the windiest day I did encounter, but hell to much for me at the time...
I was mastering up-hauling at the time ( gybes, waterstart was distant dream only), and although I could possibly represent country in world championship in up-haulig this condition were a bit scary...
anyway movie is not about Maui Robbie wizard but ordinary people like most of us.
In relative scale this was for me like 70 knots for you today..
" ... qualified to discuss here ... ??
Wind speed can actually be measured and compared using units standard units of measurement. So 50 knots of wind in Timbuktoo does equal 50 knots of wind in New York City.
Of course the effect of that wind differs from place to place and the effect also depends on the direction and many other factors. This amongst many things makes the world such an intersting place.
No, wind speed is wind speed. Doesn't matter if you are windsurfing or going to the toilet.
All those other factors you list are irrelevant.
So I get out on the old WOD with a huge centreboard with a baggy old dacron sail and get blown away in 15 knots of wind. Does that mean the wind was mental and crazy?
Meanwhile someone on a 75 litre tri fin and 5m sail is moaning about the lack of wind.
June 2010 Maui - spreckville beach - wind was 35-40 knots
At 100 KG i was using a 4.0 and was getting a lot of involuntary air time !
This pic is of a run in towards the beach where i just went over the back of a small wind swell.
Yep thats windy and so is this.
feel like something is being missed
perhaps ideally we should be discussing the windiest day one went out in and still had fun ? am sure we all have horror stories depending on our experience, equipment, etc.
people do and have died being out in hurricane weather.
when i am out in overwhelming winds, it is NOT fun.
In August of 2011 i wrote this in my windsurf journal {on my blog}
Met a fellow who was out windsurfing yesterday in Hurricane Irene. It had been down-graded to a post tropical storm, but just the same the max wind gust at Vaudreuils was 50 mph. He was out from 8 until 12 and had to stop due to the rain. With a 3.5 sail on a 95 liter board , there were times when he was overloaded !! He mentioned that it was more work than fun and quite dangerous. Almost lost his rig and apparently someone did on the east side of the island.
as long as we know the limits of ourselves, our equipment and our safety wear, let's hope we do not try to outdo ourselves 
This is a copy of my post from August 2010 that I wrote after surviving a pretty scary squall at Parham SA while kiteboarding (some on the forum said it was a microburst). The kite I was riding was 11.0 meters. I've never seen anything like it before or since:
"I went Sunday a week ago (1/8/2010) to Parham and after a few minutes of kiting in sunny weather with blue sky and 12kts of wind a cloud came and with it a 32kts squall. It was too late to land so I stayed about 300m away from the beach. After about 10 minutes into the squall (just as I thought it won't get any worse) I stopped to do a careful turn and in that instant a massive gust came and ... IT RIPPED THE KITE OFF ME!!! - leash and all!!!
There was another kiter in the area about 250m from my position, but he wasn't affected by this big gust. He also managed to chase my kite down (after it landed back in the water about 200m downwind from me). I don't want to speculate how strong this gust may have been, but just to illustrate what can happen in squally weather this is a record I found from the same day from a wheather station on Lake Alexandrina near Milang - this one is scary:"
Besides the turbulence, which is obviously a great factor, one could argue that it's not just the wind velocity that "matters", it's really the energy that the wind carries. The energy is a function of the air mass times its velocity squared. The air density (which is related to air mass) can be affected by temperature, atmospheric pressure, and humidity. It might help to visualize the difference between 1.1 kg/m3 (35 degrees hot, rather humid air) hitting the sail versus 1.3 kg/m3 (0 degrees cold, dry air), all at the same velocity. Humid air is much "lighter", because water is much lighter than diatomic oxygen and nitrogen (components of dry air), molecule for molecule.
I agree with your analysis though its over the top of my head Ian and D1.
Wind strength is difficult to accurately measure. I was just trying to make the point that measurement is objective, not subjective. So what has been measured to be a certain wind speed is that wind speed. It doesn't matter what you are doing or not doing with the wind. We can't change the wind but we can adjust our sails.
This in part makes windsurfing both the enjoyable and frustrating activity that it is.
The other factor that might have a noticable effect, especially when speed sailing on the lee side of a bank is the distortion of the profile as wind flows over a curved surface. I'd say there is a unique kink in the wind profile at Sandy Point due to this. Depending on the tides, the level of the spit there might be a metre or so higher than the water level. The one metre drop takes place over only about 5 metres horizontal distance. It's smooth enough not to cause separation and big eddies.
Roughly speaking the layer of air in the first vertical 10 metres must now spread out to 11 metres. (Not sure how close to 10metres it is, and it will be a blending rather than a sharp boundary, but for the purpose of the argument a guess will do). So the air in this layer has to slow down by 10%. An increase in pressure in the region of the bank is the only way this can happen. Pressure permeates vertically pretty well, so the whole 10 metre layer of wind will be running into rising pressure.
An adverse pressure gradient like this has, proportionally, a much greater effect on slower moving, low energy air. As a result the profile will now have a non-logarithmic low speed kink down near the surface. The kink will probably take 5, 10 , 20 or maybe 50 horizontal metres flowing over flat water to dissipate. Well beyond the sailing zone.
But not sure how big the kink might be. Be interesting to measure. But it wouldn't be easy. Maybe it's calculable? Not easy either.
In general widening an airstream exaggerates the variations in windspeed. The opposite technique is used to get a very uniform flow in windtunnels. Get the air flow as smooth as possible in a large duct and then contract it in a carefully designed funnel. A variation in windspeed of less than ±1% can easily be obtained, even though the variation might be ±20% going in.
Makes sense Ian K: At least three obvious things can happen to wind when it flows over a curved surface: Coanda Effect - the wind will follow the surface profile beyond the end of the surface; Bernoulli-related Effects - compression/decompression (pressure changes) leading to wind velocity changes; transition from laminar to turbulent flow - general nastiness for a while.
There used to be a video of Warwick from RPS on their website, but I couldn't find it. Anyway, from memory he was using a 3.5 on Port Phillip and I was gobsmacked that anyone could control a board let alone have fun!
for Ice surfing 
