US147 - tailwalk

[BelSkorpio]

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]

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]

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]

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]

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]

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]

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

reduce your fin size ,, lower your boom ,, bring the mast track a bit forward ,,

[BelSkorpio]

@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]

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!