Turn Fin Question ?

[wizard122]

Hi newbee here. I was wondering if any one sharpens the bottom edge of the turn fin to reduce lift? Or just radise it or what? I have read that you should do this to your rudder anyone have any thoughts about this also what is the best angle Thanks

[Fluid]

With the very thin section of the typical turn fin - and the fact that most now have a hook at the bottom - sharpening the bottom of the fin does little one way or the other. I do make sure that mine do not present a flat surface perpendicular to the vertical.




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[wizard122]

All SV 27 turn fins are flat on the bottom that's way I asked the question My other boats have curved fins. Won't the flat bottom cause lift?

[wizard122]

SV turn fin

Did we all forget what an sv27 fin looks like well heres a pic

[BakedMopar]

Here is some that I played around with. The ones that I use a the ones with the curved bottom. Turn sharper with less hop and drag.



George


img_0025.jpgimg_0039.jpg

[Jeff Wohlt]

I think most of us think of a turnfin as what is on hydros. What these are is a method to keep the hull from spinning....probably because the hull is so flat.

[wizard122]

Thanks but I wanted to know if you sharpen or radius the bottom of the factory turn fin will it improve the performance? some stock SV rules won't let you run after market fins. i thought that the flat bottom of this fin may cause lift.

[Fluid]

The bottom of the SV fins are not flat to the water surface whe running straight ahead. When banked in a turn the fin bottom is flat to the water, but the fin is so thin that any effect is minimal. If you do sharpen the fins, don't sharpen them so that a flat surface is parallel to the water when running straight. An angled bottom has a much wider surface to produce lift.




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[bwells]

Fluid, excellent point!