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BelSkorpio
18th September 2012, 05:19 PM
Hi,

In the weekend I was out on my US147 + standard drake 58 fin + 8.8 MegaXS (gunsails) in 12-13 knots average with peaks till +/- 18 knots. A great combi.

During a serious gust, I've done quite unexpectedly a crash, just like the one in this movie (it's not me in the movie):
http://www.youtube.com/watch?v=SQa9oPUaPWc

Luckily no damage to my gear. Only a bruise on my head because I've hit the mast.

Now, I have been windsurfing for over more than 20 years, crashed in many ways, but never like this. What would be the main cause ? Personnally, I guess my fin was too big.

Krister
18th September 2012, 05:34 PM
In the movie the sailor sheets out in the gust and that makes the nose rise. He then also leans the whole rig backwards and the sail is then pulling everything upwards rather than forward. A similar technique can be used to purposely pop a board out of the water and jump on flat water. A smaller fin would not have help here, he is simply overpowered.

BelSkorpio
18th September 2012, 05:40 PM
yes, if I look better at the movie, I see what you mean.
But I was not sheeting out. That's for sure.
I also did not have that first little chop hop.
The board flew straight out of the water.

Krister
18th September 2012, 08:13 PM
If you didn't sheet out then it may well be the fin lifting the board out of the water. This can happen if the nose is raised too much, the angle of attach of the fin then makes it unstable and it flips the board up. You can try a smaller fin, or you sail higher and lower compared the wind direction, i.e. don't stay on a beam reach for long periods of time. This is how Formulas are sailed too, you need the large fin to get a proper lift when going very high or low, but it also creates a little too much lift when reaching.

So it is a matter of sailing style, and sailing spot, if you mainly want too sail back and forth on a reach, then yes try a little smaller fin. But don't put a too small fin on it, then the board will just stick to the water.

mark h
18th September 2012, 08:32 PM
Hi Bel, were you sailing up, across or down wind? Where do you have your deck plate in the mast track? Is your US147 carbon or wood?

mcross19
18th September 2012, 08:35 PM
Sounds like you just lost mast foot pressure?

If I am well powered up I now use a Drake R13 56cm fin with my 8.6 Severne Turbo and I weigh 86kg.

Remi
19th September 2012, 02:47 AM
Hi Belskorpio,

For 8.8 is better to go to 56cm fin but this also can happen for different reasons.

In this case a big gust coming from more back in the video that make the guy open the sail and loose pressure on the mast foot, typical crash.

Difficult to give more coments with out seing the action but for sure small fin will help you.

All the best

Unregistered
19th September 2012, 03:31 PM
reduce your fin size ,, lower your boom ,, bring the mast track a bit forward ,,

BelSkorpio
19th September 2012, 04:01 PM
@markh: I was reaching, deck plate right in the middle, it's the carbon version that I have

@mcross and remi: could be that I had too much back foot pressure, I was going really fast. So you guys advice not to go smaller than a R13 56 ? What about a stiffer fin ?

@Unregistered: yes that are the classics, although I think that my boom was not that high

Thanks.

PG
19th September 2012, 05:17 PM
No need to change anything. These things happen when you are on the limit, that is just a fact of life.

I did something similar the other day when a mega gust hit the sail, it probably opened the sail a fraction. The good thing was that I managed to unhook while going nose up, and then just let go of the gear. Less damage that way!

Ken
20th September 2012, 03:06 PM
As PG said...........

On wide boards, hitting the "lift off mode" can be achieved pretty easily. Sheeting out is disaster, so it's counter intuitive to keep the power on, but you must keep powered plus downward pressure on the mast base (hang your weight in the harness). Yes, move the base further forward in the track, it will help too as well as a smaller fin.

Sailboarder
20th September 2012, 10:53 PM
Is that tailwalking?

I tought tailwalking was more when the board starts to oscilate from right to left and lift you over the water and the fin. The board nose doesn't raise much more than the back. You will get the nose up if you open the sail tough. This is how I get out from this.

This is caused by too much lenght of fin and maybe by a flexible fin too. (7.5 sail, gust of 30kts on flat water, 46 cm fin on 135l freeride board). Switching to a 40 fixes it.

Ken
21st September 2012, 02:59 PM
Sailboarder,

Yes, it is tail walking. The early stages of tail walking is much as you describe, but the nose is lifting and with enough speed and wind (+ apparent wind), the board will take off. Almost all boards will do this in the right circumstances even with a small fin (wind speed, smooth water, wide board, sailor weight, size of sail, point of sail (beam reach or higher).

With enough skill to hold down a 7.5 on a beam reach on a 135 L board in 30 knots on flat water with a 40cm fin, a 90 kg sailor will probably stay on the water, but a 70 kg sailor will be in the air.

Krister
22nd September 2012, 03:09 PM
Another thing to keep in mind is that sheeting angle is also determined by the position of the mast.
The clew might not move but if you pull the mast towards you, you are also effectively sheeting out. Even worse you have now directed the lift of the sail upwards and you take off, just like the guy in the youtube clip above.

Never let go of your equipment, that will just make things worse. Instead pull on you backhand and you either make a little jump and sail on, or you'll make a partial forward loop and land on your back without any issues.