Pistol River Shapes

 
 
Bill Thrailkill developed the Single-Twin in surfboards several years ago.  I've been enjoying it  on my 7'11" SUP for about a year now and it works great.  I have it on my 85 windsurf board now and its also amazing.  Many thanks to Mr. Thrailkill and the Swaylocks.com community.   
Picture
 


Comments

jimbo
04/29/2010 4:18pm

i was trying to figure out from the graphs (in the prior post) and from todays picture what the optimum granular size is?
MaB the lifeguard can tell us..... Dare we ask?
....to be continued....

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jimbo
04/29/2010 4:24pm

oops; .005mm.
i'll get my tape measure ready.
on a serious note, do you find the 7'11 a bit small or not? I couldn't imagine myself on a sup that small given my level of (in)expertise.

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McV
04/29/2010 4:53pm

Hey Bri what do you think is the main advantage of the Thrailkill design vs. a single fin?

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BP
04/29/2010 8:13pm

Maybe it was a 5th of something too strong for the lifeguard.

My 7'11" works great for me. I don't have any intentions of wave sliding on anything longer right now.

As for the Thrailkill ST fins on both my SUP and windsurf shapes, it feels very fast, very controlled and very maneuverable. It also bottom turns like a dream. I have not found any drawbacks. It does whatever I want it to do and it always does it with alot of speed and control. It also goes upwind really well.

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jimbo
04/29/2010 9:21pm

with two fin boxes compared to one,what about the added weight?

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BP
04/29/2010 10:10pm

132 grams for just the box, that's .132 kilos or 4.7 oz. or .292 lbs. Maybe an once or so added to it for the resin and glass installation. Its located in an area that's not as critical like up in the nose. Perhaps the little extra ballast in the fin region is actually helping out with a positive effect like proper balance.

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McV
04/30/2010 9:14am

I wonder what the theory is behind the two fins close together? Maybe it's to create a speeding up of the flow between them. Didn't you say asy fins with the flat side out works with this configuration too? Now that would be strange.
My new 98ltr. twin conversion is almost ready. fins are 16cm apart though on a very wide tail. Mine may have too much rocker for my liking. Time will tell.

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BP
04/30/2010 10:35am

Thrailkill says foil side in between, flat side facing out towards rails. He also says regular foils work fine. Its all about what's happening in between the fins. He says it will take a good single fin shape and most other good shapes to a new performance level. I can't argue at all with that. He's been surfing and shaping before I was even born and perhaps you too.

All you have to do is simply drop in 2 new boxes next to the original single and use 2 smaller fins to find out for yourself.

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