Not sure if this has been mentioned before. I'm totally intrigued by this nano technology that can keep the bottom of a board totally dry by not allowing water to adhere, surely it would make our boards faster on the water.
Im thinking it couls be a solution to prevent stuck zippers on board bags and general corrosion.

The demo's in the site are pretty cool, have a look at the link.


How does Ultra-Ever Dry work?
Answer: The bottom coat bonds to most materials and acts as a primer. It also offers corrosion protection and provides a consistent material for the top coat to bond to while interacting with the top coat to self-assemble the surface into a nano-textured surface. This surface creates patterns of geometric shapes and billions of interstitial spaces that trap and hold air creating an ?umbrella of air? on the surface of the coating. There are high points in the texture that only allow the water droplets to touch approximately 2-3% of the coating itself. The rest of the water droplet rides along the layer of trapped air. The coating also has low surface energy. It is the combination of these elements that allow Ultra-Ever Dry to be superhydrophobic and oleophobic for refined oils.


www.spillcontainment.com/products/ever-dry

This is what shark skin looks like.



Someone will come along to this thread soon and explain it better than I ever could.

evlPanda said..

This is what shark skin looks like.



Someone will come along to this thread soon and explain it better than I ever could.

Sharks aren't fast though..

?w=670&h=447

Another good one is Emperor Penguins who fill their feathers up with air bubbles before the final approach to sea ice. Then squeeze the bubbles out at the last minute to drop the friction..


With the help of Poul Larsen, a mechanical engineer at the Technical University of Denmark, they analyzed hours of underwater footage and discovered that the penguins were doing something that engineers had long tried to do with boats and torpedoes: They were using air as a lubricant to cut drag and increase speed.When an emperor penguin swims through the water, it is slowed by the friction between its body and the water, keeping its maximum speed somewhere between four and nine feet a second. But in short bursts the penguin can double or even triple its speed by releasing air from its feathers in the form of tiny bubbles. These reduce the density and viscosity of the water around the penguin’s body, cutting drag and enabling the bird to reach speeds that would otherwise be impossible. (As an added benefit, the extra speed helps the penguins avoid predators such as leopard seals.)The key to this talent is in the penguin’s feathers. Like other birds, emperors have the capacity to fluff their feathers and insulate their bodies with a layer of air. But whereas most birds have rows of feathers with bare skin between them, emperor penguins have a dense, uniform coat of feathers. And because the bases of their feathers include tiny filaments—just 20 microns in diameter, less than half the width of a thin human hair—air is trapped in a fine, downy mesh and released as microbubbles so tiny that they form a lubricating coat on the feather surface.

WA71 said..

^^ laminar flow and friction. Smooth surfaces will have more friction than a sanded surface as water will stick to the smooth surface. A sanded surface wont have the same laminar flow as the smooth surface as the laminar flow is broken up so the water dosnt stick to the sanded surface.

I think thats right

If you look at the demo on the product the water does not stick to the surface whatsoever. According to them the nano product creates a layer of nano air bubbles on the surface. Even paint didn't stick to the surface of the applied product.

If you covered the whole board it would come out of the water dry!

We have been here before, a little rough is faster.

barn said..

Mark _australia said..



We have been here before, a little rough is faster.

Why fish so slimy? Slime fast?

Same reason all your membranes exposed to the outside world have mucous too.

Not to be fast

wantmorewind said..

Mark _australia said..

We have been here before, a little rough is faster.

So why is the worlds fastest production board super smooth and glossy?????

He won't answer unless you use at least 6 question marks..

Laminar flow (what shark skin causes)is supposedly the best compromise, if the surface isn't hydrophobic, or emitting some sort of polymer, like they experimented with back in the good old days. They'd stick anything on the bottom of a yacht if it'd make it go faster back then.

If the coating is truly hydrophobic, a board should be faster with it on the bottom. Good luck trying to go in a straight line with it though

oldie said..
Something still has to support the Weight of The Rider. With 3% water contact the point loading would be several TONNES.
Which would tear off the coating?
No free lunch... maybe a 1000 cm wide board would sort of work,

Are you saying that the board will sink, because the 97% of the water will refuse to displace it?

Mark _australia said..
We have been here before, a little rough is faster.

In the demo they actually mentioned that the nano layer is a bunch of dimples / bumps, but i guess being nano size bumps it will still be smoother than a baby's bottom.

I think I might throw some on my westsuit, I like the idea of coming out of the water bone dry, like the gloves in the demo !

barri said..

WA71 said..



^^ laminar flow and friction. Smooth surfaces will have more friction than a sanded surface as water will stick to the smooth surface. A sanded surface wont have the same laminar flow as the smooth surface as the laminar flow is broken up so the water dosnt stick to the sanded surface.



I think thats right

Sounds good to me. A rough surface induces a turbulent boundary flow. Golf balls use the dimples to increase lift and reduce drag. I remember reading somewhere about aeronautical companies looking into making wings with dimples but suspected the dimples might be more effective with spin like golf balls have in flight, as opposed to linear motion.

It would be interesting to see how this layer of air effected the surface friction.

Cool videos on the site anyway

Oh yea I forgot about golf balls, Ive seen an experiment where they have a driver set up with a robot arm so the swing is consistant everytime.
The balls with dimples flew much further, almost a third from memory, that balls without dimples. Its a very good example of the concept.






^^Prototype bouncing bomb.

Skid said..

WA71 said..



^^ laminar flow and friction. Smooth surfaces will have more friction than a sanded surface as water will stick to the smooth surface. A sanded surface wont have the same laminar flow as the smooth surface as the laminar flow is broken up so the water dosnt stick to the sanded surface.



I think thats right

Doggie, I have a vague recollection that the sanded surface traps a thin layer of water and then this layer 'slides' over the surrounding water.

The theory being that the 'water to water' friction is less than the the 'water to board' friction (on a super smooth board).

I've read somewhere (but am too lazy to google now) that 800 grit wet and dry paper produces a surface that is about the optimum 'roughness'

I used some 600 w&d on my shortboard (quad) and its even quicker down the line, I do the same to my fins as well

I think your explination is a bit better than mine

I've been using Harken McLube, largely used for racing yachts like the Farr 40's, Melges 32's. No idea if it's making any difference on my Falcon 99, but it makes me THINK I'm faster