RealSurf Surfers' Forum

From SW297 - the India issue. This is Greg Webbers email response to the article on Derek Hynd's finless surfing - "fins do drag, so the motivation is not so bad to diminish that aspect, but it's to do with the ratio between the drag of the leading edges and the surface area, no more than that. I'm in the process of making the thinnest fins ever in surfing. So little drag yet huge contact with the wave face and even deeper into it. Bigger, thinner, longer fins slicing deep within the wave itself."


Sounds promising, what do you guys think of it?

On a side note, it sounds like he might be able to chop my Achilles tendon clean in half with it.

Sounds like a tuna fin(they go pretty fast) .But by going longer and narrower wouldnt you still be retaning the overall surface area as a shorter widder based fin? Its got me f#%k3d how they get this friction free buissness anyway .If youve got one surface moving over or within another surface there has to be friction right:idea:.The closest Ive seen to friction free is laird hamilton on that hydrofoil thing riding big ocean swells .,practicly no surface area touching the water at all.

I just thought it was cool that someone stood up to Derek.

Sounds a bit simplistic. Drag also comes from turbulance. You can make pretty fat fins that won't have any turbulance. Foil design is a science and there's guys out there who've thought a lot longer and harder about it than GW and have the tank testing to back up their designs

pinhead wrote:Sounds a bit simplistic. Drag also comes from turbulance. You can make pretty fat fins that won't have any turbulance. Foil design is a science and there's guys out there who've thought a lot longer and harder about it than GW and have the tank testing to back up their designs

^^

I'd just add that there's no fin ( or airfoil or hyfrofoil ) that will have zero turbulance at all velocities, and all angles of attack - just some foils are more tolerant to changes in these parameters than others. In terms of leading and trailing edges, think of a cylinder as one extreme, and a flat sheet as the opposite extreme.

Control surfaces on surfboards are all about compromise, and they have to cope with constant changes in velocity, direction and surface conditions ( glassy, broken water,fast racy / steep waves, slow less steep / fat waves ). Cavitation is also an issue in hydrofoils that can spring up unexpectedly.

I think there's still a lot of tuning that can be done for a given wave or day with the existing parameters. I know a former state longboard champ that has spent hours in his shed sanding Fluid Foils fins to tweak them. He reckons he gets a significant performance advantage by doing this - and the proof seems to be in the pudding.

I also think there's a lot of potential in changing the fin's surface in some way to reduce friction, e.g. coating it, or putting small dents or grooves in it. I plan on testing the groove theory myself in the not-too distant future, as this has been thoroughly proven by years of hydrodyamic engineering ( subs and I have heard some torpedoes use them ).

You might think that the ultimate fin would be immeasurably thin, a one-sided foil made from incredibly strong material. But properties like cant and toe would become super critical with such a fin - I suspect almost to the point they would anhialate any gains made in reduction of leading and trailing edge drag by such thin sections. As pinhead pointed out... turbulance is always there, lurking... waiting to bugger things up.

I seriously doubt anyone can come up with one fin / foil that does everything. Doesn't mean they should stop trying though.

Such a long discussion,

So many variances,

Agree'd Dino....

Greg want's to innovate in many area's still, Real idea's...

dUg wrote:You might think that the ultimate fin would be immeasurably thin, a one-sided foil made from incredibly strong material. But properties like cant and toe would become super critical with such a fin - I suspect almost to the point they would anhialate any gains made in reduction of leading and trailing edge drag by such thin sections. As pinhead pointed out... turbulance is always there, lurking... waiting to bugger things up

I agree there dUg...I think any too-thin fin or very sharp leading edge will create problems when a "surfing-like" angle of attack is introduced...i.e - direction change off dead straight. A thicker fin will handle direction changes and turbulence better.

And DH...well, the finless thing would have a great fun aspect...but see, those boards he rides, shaped with all the rivulet-creating channels in the tail? Why...To create drag, which attempts to stop the board going sideways. Its a less effective FIN!!!

The drag-less fin might as well be an imaginary fin..its not going to happen. If you make one which slices more efficiently, it needs, as GW stated, to be deeper, so as to create sufficient drag!

Maybe the same thing can be achieved best with a little cylinder poking out the bottom of a board a couple of inches?...no angle-of-attack issues.

Josh
www.joshdowlingshape.com

So this is possibly what he had in mind with his new fins?

http://www.webbersurfboards.com/ - Check out the "Almond".

Looks intriguing, he always comes up with things that "look" very different to what is out there. Is this part of how he differentiates himself from other shapers? Or is this to do with his openness to new and unusual shapes and designs that actually happen to work well?

His Dad is also an extremely intelligent, open minded and articulate gentleman.

A big influence I'd reckon.

Cpt.Caveman wrote:http://www.webbersurfboards.com/ - Check out the "Almond".

Checked it out but a bit too sci-fi for my liking.

What really struck me is that he looks like a cross between me, one brother and an uncle. If you did a face mash-up I'm sure it would come out as Greg Webber. Had to double-take when his picture came up. :?

i have some fins that have very much less friction or drag than any others I have ever used....but the reduction in friction means big reduction in drive, so I am either gunna have to go big or reintroduce some friction bit by bit til I find the happy blend of speed/drive, friction/drag...maybe just taking the fins out is best way to reduce friction drastically, but then no control, there's the challenge to have no drag, but still sufficient control....Greg does some good stuff and tries different stuff...

dinosaur wrote:To be honest I think its more to do with gregs personality as a bit of a showman or show off. He likes to be on the outside, likes the attention he gets from creating something that looks weird and maybe controversial. It just so happens he's got the skills to back it.

Along the lines of the above , does Webbers different designs equate to sales especially locally where he is shaping from ? or do his 'webber' customers stick to his more convential shapes ?

Anyone know ?

Most Webber boards that I notice in Sydney are the Afterburner, Fatburner, and to a lesser extent the epoxy standard shorty.

I've only ever seen one other Mini-Fish twinny, and one Spoon in water.

It seems as though most people go for his more "normal" shapes. I've never seen anyone with his new performance twin-fin or pin-tail twin-fin, nor his new Almond quad.

There are a few of the "öther" shapes up this end of town. Av/Whaley

Fin design has always been an object of contention between my mates, so much so that one of the guys I went to Uni with ended up basing his thesis on it. He also got funding for the research from FCS.

After heaps of testing on commercially available fins and some experimental ones he concluded that at a certain velocity, everything from width, flexibility, friction and thickness are critical. Thing was this velocity is well in excess of anything your board acheives.

At normal speeds, the only thing that effects performance is the length of the leading edge (and area as a function of the leading edge) and to a much smaller degree, flexibility.

Im of the opinion that half of fin performance is mental, pop in small fins and you will surf looser.

Hey Jammin,

I'd like to read more of your mate's thesis...or at least the summary! Would he post it?

Agree on the speed of surfing being low, but personally have joy with a thicker foiled fin.

Josh
www.joshdowlingshape.com

jammin wrote:At normal speeds, the only thing that effects performance is the length of the leading edge (and area as a function of the leading edge) and to a much smaller degree, flexibility.

Always knew this, but it's got me thinking about the new super short revolution that's currently going on.

I assume that even though the boards are shorter (5'6", 5'8" etc) there's little difference in leading edge and just less nose area that doesn't have a lot of contact anyway?