Forums > Windsurfing   Gps and Speed talk

Fin Shortening

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Created by TerryF > 9 months ago, 22 May 2010
TerryF
WA, 60 posts
22 May 2010 8:45PM
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I have a selection of 3 freeride fins that cover the range of wind strengths that I ususally sail in. I'm pretty happy with the fins except that as my speed has increased I am finding that as a relatively light weight sailor (73kg) they generate a bit too much lift (the board rails up as the speed increases).

I've considered buying a smaller fin but having noticed that some of the newer fins now have a very square tip I wondered if shortening the end of my existing fins to a square instead of pointed tip would solve my problem (at a substantially reduced cost).

A reduction of about 2-3cm is what I had in mind. Is there a risk of reducing the fins performance (i.e. a greater increase in drage than the reduction in lift).

Terry

agrelon
51 posts
23 May 2010 7:23PM
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TerryF said...

I have a selection of 3 freeride fins that cover the range of wind strengths that I ususally sail in. I'm pretty happy with the fins except that as my speed has increased I am finding that as a relatively light weight sailor (73kg) they generate a bit too much lift (the board rails up as the speed increases).

I've considered buying a smaller fin but having noticed that some of the newer fins now have a very square tip I wondered if shortening the end of my existing fins to a square instead of pointed tip would solve my problem (at a substantially reduced cost).

A reduction of about 2-3cm is what I had in mind. Is there a risk of reducing the fins performance (i.e. a greater increase in drage than the reduction in lift).

Terry


How good a job you can do strongly depends on what the fin is made out of. Is it a G10 or Carbon?

Might be worth the risk...

TerryF
WA, 60 posts
23 May 2010 8:53PM
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The fins are all g10

Bender
WA, 2235 posts
23 May 2010 9:56PM
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PM Elmo he can set you straight on re-boxing fins. Its really easy once you have made a jig. Quite a few of us have been doing it to make decent weedys that go fast

I'm pretty sure the red muppet would be happy to do them for you for a small donation to his windsurfing budget

TerryF
WA, 60 posts
25 May 2010 9:15PM
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Thanks for the suggestion Bender, I might just have to do that.

decrepit
WA, 12767 posts
25 May 2010 11:01PM
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I think it depends on the fin's angle, a more upright fin is more affected by induced drag, if the tip is too large.
So for an upright fin, you can either do as Bender suggests and rebox it shorter, or cut of the tip, but try and maintain the original taper, and then grind/sand it to recreate the foil. If it's a weedy at 45deg, cutting it off along the water flow, (parallel to the base), may be OK. (one of our guys has done this and still got good speeds.)



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"Fin Shortening" started by TerryF