What is the preference these days. A lot of the wings come with a polished glossy finish that is very smooth-very pretty. But all the racers sand there wings with various grits. I understand the idea of having the wing a bit rough; say 800 or 1000 Grit to try and Achieve that "attached flow" barrier of water on the wing that is supposed to make it feel slippery underwater, since water passes over water faster then water on a smooth polished wing. I found the original first gen Pryde wings had that finish from the factory it wasn't too smooth had a little bit of grip to it when you run your finger across it and those were slippery and pretty fast wings, tippy as hell though. So last night I lightly sanded my infinity 65 front wing using 1000 grit sandpaper. I went across the trailing Edge and leading-edge then finished with sanding back and forth in the direction of flow. It doesn't look as pretty as a new Mirror like finish since you can kinda see sanding strokes now but hopefully I can get some more performance out of it. Will see this weekend. I also did the same to me rear stabilizer wing. Maybe 1000 grit will be somewhere in between attached flow and smooth. A few years ago I heard after 400-600 there is no attached flow so its still a little blurry to me on what grit attached flow happens at and what is beneficial or not.

What finish are you using on your wings?
Is a lower grit recommended for free riding with big low stall speed wings say 400-600 and a higher grit for race Wings that are trying to achieve high speeds say 800-1200

Maybe some racers or physics brains can shed some light here

My 2 cents (short form)


leave it as presented. Any difference will be so negligible that you'd have to be in a fluid dynamics lab to discern it.

A bit longer:

My "armchair scientist" opinion is that if you achieve laminar flow, you're actually generating drag. Each successive layer of water is in fact dragging on the next (slower travelling) layer. Laminar flow in the same medium is great as a party trick to show a 5 yr old, But in my opinion, the only way to see any speed benefit in the real world is to have a different viscosity boundary layer than the surrounding liquid. They did that with polymer emitting yacht paint a few decades ago. Apparently it worked quite well, till someone pointed out that it wasn't very good for the environment.

Go for turbulent boundary layer...fine sanding. See this earlier discussion

www.seabreeze.com.au/forums/Windsurfing/Foiling/Surface-prep-foil-wings-and-masts-

Select to expand quote

oscardog said..
Go for turbulent boundary layer...fine sanding. See this earlier discussion

www.seabreeze.com.au/forums/Windsurfing/Foiling/Surface-prep-foil-wings-and-masts-

Just watched that great video JJ posted, as Subsonic allotted to as luminar being pretty to look at but not efficient with wings as we need a boundary layer.

I will try Remi Vila's method from that video. I love how his singing broke the live feed for a second
Only if my foil sang like him.

When I make a repair to a wing I finish with 3M 1200 wet/dry sandpaper (black in color), it closely matches the original finish on the AFS wing and stabilizer. The only painted/colored surface on the Wind95 foil is up by the top of the mast where the AFS logo is, same for race foils by AFS and other companies.