Photos that Help Us Redesign Boards?

[Headwax.]

tracks march 1976

photo simon chipper (one time kneelo )



First line reads "The Kewarra jet bottom design is made to use water and not allow it just slide by ...."

that Fat Man he do sing loud

no waves here today

(just surfaced film of the last Sitmar Cruises and one loccal Maroubra club contest circa 1978 - one wave each by a 17 year old (?) David Parkes and a red haired guy whose name I just forgot.... Terry Day )

[skansand]

i want one

[Headwax.]

Well this thread went off like a virgin lassie at the Beltane Fires

Well I do like to blog heh

Meditations on squared rails:




close up photo of cutty courtesy of Mrs Satchell (thankyou very much:) )

Looking at the back rails you can see a sudden break in the water

flow where it is coming off very freely, compared to the rail just in front,

of my ankle where the water is creeping up the rail held by meniscus.

tension

The point where the water starts to break cleanly is at the wing, but it also

at the point where David has made the rail in a pronounced (but thin)

square profile so that the meniscus is broken at both the top and the

bottom of the rail.

And what's the point?





Photo Courtesy Mrs Satch

You can see how the rail is acting in the water in the above picture.

Interestingly the effect of the rail is seen through the water -

as a small streak of light tracing the line of water dissociation from the rail

at the point where the square edged rail starts.

lots of other interesting bits in this photo ....

eg the concave is still 14 mill ....
eg the "Headwax Effect" in action in a quad....
eg how much rail is in the water and the consequences
of a nose vee in this situation
eg how much pressure is over the front fin compared to the back fin

[frankfqr]

Headwax--Your photos and descriptions do open up a larger can of worms for me. Pinpointing something we all play with in terms of preference of style and approach. Those that choose to fly about on the face might lean more toward the incorporation of the harder edge thru out the rail foil, utilizing chine placement nose to mid point, fine tuned in the hands of today's shapers and the speed will increase noticebly. But, if we boil it down to that sweet tube ride!!--then what would be the preference? Should we have the speed rail so we can fly thru the bowling sections, or should we have the large round curved rail so we can control, use it's holding chacteristics to caress the face as were suspended on edge. Release or Hold? In the hands of a gifted rider, he'll be able to tap the waves optimum line for speed regardless; but condense that moment of tubed bliss and what should it be, Release or Hold?? Cheers...Frank.......

[Headwax.]

gooday frankfqr

good question... got me thinking .... surf blown out today

I think that a rail desgigned to release at one point can also hold at another.

EG a square rail. Seems stupid at first eh?
Who'd put a square rail on their board?
It would obviously catch etc.
As far as burying the rail - it seems obvious that
a curved rail would sink better than a square rail.

But there's another way of thinking about it.

Suppose the square rail had good water release
at the top and bottom, wouldn't it be possible that
the rail would sink further than a softer rail of the
same rail because of the reduced meniscus pressure?
And remember that the top of the rail is flat so not
presenting a surface to the water that would stop it burying.

And in sinking further there is more board to push
against in the water. IE in providing more water
release at the edges we are actually increasing
our ability to hold the rail in the water because it
is buried deeper.

In practical terms, putting a resin edge on the bottom
of a board means that you can push the fins up
about 1/2 cm and have a looser board that holds better.
Same board, different rails, better release off the
edges but crisper hold. Imagine what doing
the same thing at the top of the rail might do?

So

Release or Hold?

Maybe they are the same thing.

PS sorry about not replying to your PPM yet.

Had a mind infarct.

And BTW, thanks for showing interest in this thread..

Mactavish I have heard trialed square rails. But found two much water sat on the top of them. Maybe he had them in the wrong place....

You can see the water travelling up the rail here in front of the first wing, but where the square rail starts there is no water travel





photos Mrs Satchell
===========================
Oh I think I like this thread better viewtopic.php?t=2794

[frankfqr]

sorry mr. wax, those pic links didn't come up for me? Interesting concept. One thing I'm left hanging with is the unknown with things like pic 1 of the post, all that water being drawn up the tail an Slater's board. Would make since if we knew it was a tri-fin with the water wrapped around the fin. And if it was, would that be a big advantage if it was a quad with concave, hence no additional interference mid point, pure release?

[Headwax.]

good question


...... way to break up the clingyeffect would be to introduce bubbles or have a very scratched surface or to have a polmylar compound that set like fish scales (each fish scale provides a point of release - tested on USA Subs in the seventies to reduce friction - don't what came of it Name Denis Savage rings a bell)

maybe the tendency of water to stick to our boards is good ....

but I don't think so

concave is interesting cause at what point does it cease redirecting water and direct air?

[Beeline2.0]

..

[Headwax.]

quick as a flash Beeline2

from

http://www.memagazine.org/backissues/me ... _note.html

Biologists have long wondered why the skin of dolphins was so, well, flaky. In what is an extreme instance of underwater eczema, the soft, outermost layer of skin is completely shed every two hours.

Japanese engineers believe they now have the answer. In a paper published in the May issue of the Journal of Turbulence, Yoshimichi Hagiwara of the Kyoto Institute of Technology and his colleagues report that the flaky surface reduces drag, enabling dolphins to slip through the water.

This isn't the only hydrodynamic trick dolphins have up their sleeves. Their bodies are extraordinarily streamlined, which reduces both form drag—the pressure of water against their skin—and drag due to friction. But to understand the role the skin flakes have on reducing drag, the Japanese researchers constructed a computer model so detailed it accounted for every single flake on a typical dolphin's body. Not only does the wavy contour of the skin reduce surface friction, but the peeling off of skin flakes disrupts drag-inducing vortices that form as water slips over the dolphin's body.

The physicists verified the computer model by immersing a flake-covered plate in a test tank.

The concept needs to be studied further, the researchers say, but may someday be applied to the hulls of boats and submarines.

maybe you could have a dandruff dispenser at the nose of the board as well

cheers

HW

[Headwax.]

interesting coating for medical instruments

How does LubrLAST work?



LubriLAST™ is part of the BioLAST technology platform. The supporting polymer network characteristic to BioLAST is crosslinked and covalently bound to the substrate. This network is normally non-swellable in water. In LubriLAST™, a long chain, biocompatible hydrophilic polymer is incorporated into the coating. Part of this long hydrophilic polymer becomes entangled with the supporting network while other part remains exposed and able to become hydrated. When in the presence of water or body fluids, the hydrophilic polymer adsorbs water molecules to create a watery interface at the surface of the device. The water cushion reduces wet friction, protein adsorption and cell adhesion.

[Headwax.]

superhydrophobic nanopin film gives a contact angle of 178 degrees so water droplets make spheres .......

Nanopin film is an experimental material in
nanotechnology developed in 2005 with unusual
superhydrophobic properties [1].
A droplet of water makes contact with the surface
of this film and forms an almost perfect sphere
with a contact angle of 178°. The film is able to
do this because it is covered with nanoscale
topped off pins or cones perpendicular to the surface.
The surface is regarded as a composite material
with mostly air and a small fraction made up by
the tops of the cones.

pic on left is overview of pins and cones, 1um
middle picture must be a cone (?) 20nm

you can see it would be like riding across
ball bearings of water


now how interesting is that?

[willli]

http://www.youtube.com/watch?v=LGB8P9g7830

[Headwax.]

hello willli



nice bikini, always was partial to a bit of bondage...

can't wait till I get home to hear it with sound ...is that a tautology?

looking at that bikini.... just occurred to me
a perfect frictionlesss (board) bottom
would mean that we would have to
increase the size of our fins...

or would we?

[CONTIKI]

WHAT KIND OF POLE?

[Bryn]

Fascinating thread as always Mr.Wax! Following with interest but can't get my head around a genuine contribution yet

My only thought is on your last point, if the bottom was totally frictionless surely upping the fin size would be contradictory and add more friction and drag again? Or would the fins be frictionless also? Would fins work as well if they were frictionless?