AND, NotWal and I have almost 8000 posts between us to your 210, that must make us much more knowledgeable, almost experts in fact
sorry, I thought we were talking about windsurfing not frign gardens
you two obviously havent done much sailing or windsurfing.
I guess I forgot the golden rule of the forum DONT FEED THE TROLLS !!!
isn't debating water beading or not basically a waste of time... i'd would have thought you guys would be more interested in talking about dynamic flow.
interestingly, stuff like lasers and such are generally going a lot slower then a windsurfer, and water over the hull could possibly be laminar, whereas windsurfers are usually going a fair crack faster where flow would definately be turbulent... so saying what applies to boats also applies to windsurfers is kinda silly.
it doesn't surprise that some literature suggest polishing vs some that says sanding. I'd say undoubtedly at low boat speeds where laminar flow is maintained a polished finish would be better, but once you start going faster things get trickier.
Interestingly BOR90, the trimaran that took the americas cup and also does almost 30kts in 10kts of wind uses a "skin-friction reduction riblet film" made by 3m. Thats much closer to the speeds that a windsurfer does so maybe you should be getting some of that if you are really serious about the whole surface finish thing.
valenciasailing.blogspot.com/2010/03/bmw-oracles-skin-friction-reduction.html
I am a bit low on posts, therefore no expert, but the advice from Board Lady is not for a glossy surface.
boardlady.com/fast.htm
gawd I hit 50kts on a board I covered with wax polish... if only I wet sanded it 
Makes a huge difference on fins. Lately I've been sanding everything. How scientific of me.
I never really bothered much with my sailboards, cos speed was not my goal, but I do know that whenever I polished the bottom of my surfboards, they always went heaps better.
I always favoured a polished finish, rather than the lazy wet/dry they do now.
Hey slowy, where'e me flippin' fin, and where have you hidden the bloody KA crew ?
No-one's answering their e-mail. Not even Gestalt.
Was there an apocalypse ? Will there be zombies ??
Should I do some extra cardio this morning ??
Save a bit for your pencil as well.
has anyone tryed the 3m foam pads (fine ) they are amazeing you can use them wet or dry even dry they dont scratch, just add a bit of shampoo to the water
I don't do anything to the bottom of my board cause I don't wanna ruin how purty it looks 
Select to expand quotekato said...
[quote
Your bang on. Technique, fitness and correct equipment selection are much greater factors in overall speed. We're really just talking about that last 5% of potential speed that you'll only achieve if you keep your gear in top shape. You know, polish your fins and board, tune your sail, play with mast, boom and harness position etc until everything just hums. Being a gorilla also helps when it's windy!
Where do you get a Gorilla from 
LOL! I've seen them at the PIT on windy days and they FLY. I just THINK like one and that helps a bit. 
I wish I had the time to test all this on a windsurfer. 
Anyway, there are plenty of examples in nature of hydrophobic surfaces, such as penguin's feathers, grasses or lotus leaves that have driven us to develop hydrophobic compounds. These compounds can make the angle of incidence of the water to the polished & coated surface approach 180degrees so that the water is practically not touching the surface.
My two cents...
My understanding is that if the shape of the board allows for laminar flow. Then polishing would probably the way to go. Certainly some airfoils are capable of laminar airflow so the planning section of speed board might be up to it.
With true laminar flow the layer of water of close to board should not move at all, the next layer moves a bit, and the next a bit more etc utill you get to the layer that is moving at the same speed of the board, and very little drag.
When you can't achieve a laminar flow, one technique to reduce drag is energise the layers close the surface (the boundary layer) with say dimples on a golf ball, a special surface, bleed air or other tricks, perhaps a sanded surface would work. This has the effect of stopping the boundary layer, becoming even more turbilent and interfering with the rest of the flow, allow the rest of the flow to remain laminar reducing drag.
Then again this is all ignoring the mechanics of the board which is planning and I reckon if you took into consideration all the factors, you'e brain would explode.
I wish I had the time to test all this on a windsurfer. Anyway, there are plenty of examples in nature of hydrophobic surfaces, such as penguin's feathers, grasses or lotus leaves that have driven us to develop hydrophobic compounds. These compounds can make the angle of incidence of the water to the polished & coated surface approach 180degrees so that the water is practically not touching the surface.
Still not sure but this happened gpsteamchallenge.com.au/sailor_session/show?date=2010-09-16&team=16
gpsteamchallenge.com.au/sailor_session/show?date=2010-09-16&team=16
looks like this post has been stagnant for a bit but I recently came across an interesting finology article on vmgblades.com (excerpt below) and couldn't help but wonder whether principles of laminar and turbulent flow apply somewhat the same to the bottom of boards as they do to fins?
Finish & Flow (of fins)
Finish is how the surface of the fin feels and has a large part in how the water flows over the foil. This is why looking after your fin is very important. Nicks, scratches or dents all affect the flow and can create drag or separation bubbles. If you have a tendency to spin out unexpectedly, then this is the section for you to read.
Laminar flow is where the water stays attached to the fin and follows the foil shape closely. Theoretically this creates the least amount of drag (always a good thing as we want to minimise drag). However, laminar flow can stall dramatically and you find it much easier to spin out. This is because large separation bubbles happen in the boundary layer of the water flow around the foil. The separation bubbles separates the fin from the water, you suddenly have no lift and you spin out.
Turbulent flow is like little swirls of turbulence along the fin. More energy is created in the boundary layer and the separation bubbles are tiny. As the bubbles are tiny, stalling is less likely to occur and a rider is able to push against the fin as it is more stall resistant. This gives you more control and allows you to be more daring in your tactics. There is slightly more drag but at least you don’t have to worry about spinning out in the water.
A rougher finish forces a fin into making turbulent flow and a smoother fin is more likely to become laminar flow. Sailors often experience different sensations when sailing new fins. This is because of their style and experience. It can also take a little while to get used to a new fin and adapt your style. Different finishes could be recommended to different sailors, this is so that you get the best possible ride for your style.
If you're also into polishing and waxing your car then maybe you should read this:
www.madsci.org/posts/archives/mar97/858179474.Eg.r.html
