Old 4th December 2006, 04:36 PM   #11
NiklasR
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Default RE: Double fins?

Thanks everybody for good answers. I am more than ever interested to try a board with two fins. Both for shallow water purposes and to try the performance and upwind characteristics.

Still no info or answer from the Starboard team...? It would be nice to stay with the same brand and it would be interesting to hear what they say. If it is as GEM says that in marginal to powered up conditions the tow fin configuration is faster and points higher it would be highly interesting to look into, or?

Regars,

Niklas
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Old 4th December 2006, 08:00 PM   #12
Roger
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Default RE: Double fins?

Hi Niklas,
I would take what GEM suggests to the full explanation from my experience with twin fin designs (like the HiFly MADDs).
They are faster and better upwind (the twin fin design) ONLY if you are in water so shallow you cannot use the right size single fin, or a modern progressive rake weed fin.
My experience in Bonaire (a very shallow place where it's impossible to use fins much over 33 cm) was that for the larger Carves, and any of the wide boards (Starts, Gos, Rio's, Easy Riders), the "cut down to 33 cm" fins the rental operators must use for the super shallow conditions didn't work very well and the boards were hard to get on plane, and not real fast as there was not enough fin span to "ride the fin" on a single fin board.
I tried the HiFly Madds (mid size and large size) and they were better with the twin fins, in the shallow water areas, but the Carves and other wide boards were better upwind, faster, and earlier to plane when you could use the regular size single fin further down Lac Bay in the deepwater channel.
Also, I felt that the " fin toe in" on the MADDs might need to be adjusted as one of the fins always seemed to be slightly "spun out" (evidenced by the white turbulent "wake stream" behind the (usually) upwind fin when trying to sail the board "on the fin" with a slight bit of leeward "railing".
So, I don't think you will see any "twin fin" designs from Starboard (in the freeride design range) anytime soon.
Twin fins do work, sort of, but only when the water is too shallow to allow the use of a correctly sized (for the board's tail width, footstrap offset, rig size, and sailor weight) single fin.
A deeper single fin has less drag, better early planing, and significantly better upwind angle than 2 smaller fins.
The modern progressive rake weed fins (Tangent Dynamics Reaper,
Tekkno Sports Race Weed, True Ames Shallow Water Weed) and the Wolfgang Lessacher Duo Weeds give very good performance (almost as good as a vertical fin design) and certainly better than the twin fin setup, when there's enough water depth to use the correct size.
These are not to be confused with the traditional very swept back (> 45 deg.) weed fins that stick out behind the board.
Hope this helps,
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Old 5th December 2006, 09:05 AM   #13
GEM
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Default RE: Double fins?

I agree with Roger.

Twin fins are better under limited circumstances of sub-optimal fin choice in the single fin board because of wind / depth conditions. In that circumstance, they are demonstrably superior.

I would point out that there are only a very few shallow / wide fins for single fin boards, and I'm not certain how they would compare.

Certainly, experience shows that the fastest configuration is the minimal fin that allows planing, and the highest efficiency is a high aspect ratio pointer. So when water depth is not limiting, I can't imagine a single fin not being superior.

Just ask yourself....when's the last time Boeing made a biplane?

GEM
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Old 5th December 2006, 06:31 PM   #14
NiklasR
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Default RE: Double fins?

Haha I can se your point. It would be quite funny to see a plane with two wings on each side.... Well I will stick to my Carve and F-type boards with large fins and walk the distance to the deeper water.

Thanks for all the answers.

Best regards,

Niklas
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Old 5th December 2006, 09:12 PM   #15
Roger
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Default RE: Double fins?

Hi Niklas,
Unless your winds are straight onshore, try learning to sail your board backwards (fin first).
It's easier than you think it might be, and when you sail with your weight in front of the mast foot, the tail is lifted quite a bit and you can sail pretty well in very shallow water.
The Formula guys all do it, and I've found it to be quite easy as long as the wind supports going away from the beach or back to the beach on your way in.
Hope this helps,
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