Forums > Windsurfing General

Re-shape a fin

Reply
Created by Obelix > 9 months ago, 2 Jan 2022
Obelix
WA, 1131 posts
5 Jan 2022 3:13PM
Thumbs Up

Haven't done the wet sanding. I could, have enough wet sanding paper.
What will the difference (in performance) be between the 320 dry and 600 wet? Or is it just the looks?

decrepit
WA, 12776 posts
5 Jan 2022 6:28PM
Thumbs Up

That depends who you ask, some say 400 is all you need others that a high polish is faster. It's all about boundary layers, and how good the foil is. I'm fairly sure Mal Wright said a while ago, that a high polish is only useful on a really good foil. If it isn't a good foil, polish can lead to ventilation, the water doesn't stay attached as well.

Fangy usually goes for a high polish. Personally I haven't noticed a lot of difference.

Obelix
WA, 1131 posts
9 Jan 2022 8:17PM
Thumbs Up

Tried it in Cervantes.
Stil well planted with a noticable speed improvement. Pretty happy with it now.
I won't be reshaping it any more. Maybe just give it a once over with a 400 grit.
Thanks guys.

decrepit
WA, 12776 posts
10 Jan 2022 8:41AM
Thumbs Up

I was touching up a few fins for Saturday's blow, and thought of this thread, so I took this pic of my work area.
If you're serious about shaping fins, this a good setup, a horizontal vice, is much better than g-clamps. And angle and height chart, with profile gauge, and not very clear here, but over the top of the chart is my print out of 8% eppler foils. fairly happy with the mods to this fin. It's for weed growing on the bottom. Most of the blade is at 47deg increasing at the tip. Higher aspect ratio than the deltas need for surface weed so better in chop. This was needed Saturday as there was a big storm surge, making liptons more choppy than usual. Although I'm not used to trimming for chop, I still managed 37 knots with it.



Obelix
WA, 1131 posts
11 Jan 2022 6:44AM
Thumbs Up

I'm nowhere near these speeds on any fin
The fin fits what I need in the conditions I usually sail so I'm happy with the outcome.

Your setup is very interesting. The horizontal vice is a great idea.

I am not very good with my hands (or with my patience) and don't have a technical education to understand the science behind the fin design, so unlikely to do much fins shaping in the future, but if was fun to to work on this one.
Thanks for you input with this one. Made a lot of difference to this fin.

decrepit
WA, 12776 posts
11 Jan 2022 8:41AM
Thumbs Up

Select to expand quote
Obelix said.. >>> but if was fun to to work on this one.
Thanks for you input with this one. Made a lot of difference to this fin.

Well that's what it's all about. Fantastic that it worked for you.



Subscribe
Reply

Forums > Windsurfing General


"Re-shape a fin" started by Obelix