Wow, Snake Oil.
I guess just to be mentioned amoung those with far more superior minds than mine (well, not sure about the Pope) is a compliment.
Just trying to further the evolution of these craft we ride called “surfboards”.
What’s your contribution?
And yes, leverage is your friend.
Show some sort of test/result/credible theory to validate the concept of torsional propulsion being applicable to a surfboard.
If not, its on the Rudolf Steiner level. Complete bullshit, but can`t deny anyone the right to believe in it.
Edit:
The idea of wigglig back and forth works on the snakeboard, But the mechanical transmission of force is way more direct between a hard surface and the snakeboard than through surfboard and water. We do kind of ticktack back and forth on a thruster to get some speed in desperate times just like a skateboard though.
Theory
A theory can be a body of knowledge, which may or may not be associated with particular explanatory models. To theorize is to develop this body of knowledge.
First off, I have no interest in a pissing match with a scientist.
I do not have a doctorate in physics.
What I am is a surfer.
Life-long.
I also have been fortunate to work as a professional in the surf industry for 30+ years.
Worked side by side with many of the industries best,
One of surfings greatest surfboard designers Dick Brewer.
He has had more influence in surf design than almost any other.
He taught me to take the engineering approach to surfboard design.
So I have a great passion for all things surfboard design.
From design, to foams, resins and composites, and construction.
I have worked my way up from the broom pushing dust,
Done absolutely every job involved in surfboard production.
Glued blanks.
Production shaper, laminator, sander, fin maker, fin and hot coater, airbrusher, gloss and polisher.
The list goes on and on.
Worked on World Champions boards.
All this experience goes into every board I build.
I know some stuff.
Also as a rebelious Punk Rock type, I question everything.
My theories are not just ideas.
I first rode one of these 4 years ago.
Rode the crap out of that board until a big 6-8’ south swell snapped that baby. (Pulling into gapping barrels).
I know it works.
I want people to feel what I did. And further surfing performance.
You can talk and guess all day about design.
I surf mine for assurance.
And I proudly put my name on it!
Innovation. Not imitation!
So, I ask again.
What have you contributed to the surfing world?
I love this place.
Endless innovative energy!
https://www.youtube.com/watch?v=EbZwknaIqqE&list=UU4GOUNl6TtxikZS-y1BliuQ
I would think the greatest attribute of the design would be the change in rocker (increased) as the tail flexes making turning easier.
i think it would be really interesting if the board could be made with no tail rocker when unloaded, but a flexible enough tail section that when loaded could have a variable rocker.
Really nice seeing someone expand the envelope of design.
Some of my early designs, the split was further up and there was more tail area without stringer.
The curve of the stringer was also straighter.
So I have since been bring the stringer out at a more excellerated curve.
A flatter tail rocker was shaped in hope of it flexing more and bending as the board turned.
Some had too much flex and lacked drive even with the flatter rocker.
Too much flex is lost energy.
Kinda floppy feeling.
Keeping the end point directly under the rear foot feels good.
That’s where the Torsion comes from.
I may not agree with Mr. Snyder’s flex propulsion theories. But I believe he has created a design that has unique torsional tail flex performance.
He has presented enough of the design visually and with text that if one has a solid enough grasp of the basic concepts in physics, one should be able to reasonably consider the potential performance effects of this design.
BTW it is my understanding that Dick Brewer designed and raced experimental RC airplanes.
I’m not sure I buy flex propopulsion but unlike some other concepts drifting around I can see this would work.
As the board is loaded into a turn it will flex effectively increasing rocker, this shoud allow the surfer to turn tighter with less loss of speed, like a slalom skier. If there is too much flex the turning force will be centred over a very small area of hull with the most flexed areas giving less pressure for the surfer to push against (loss of drive). As the surfer exits the turn the board should unload, as it does the rocker iunder the feet will reduce, as the rocker reduces this evèns out the the pressure distribution over the hull but also tipping the board down the face of the wave at the same time as reduce drag a little. Whether this counts as propulsion or not I don’t know.
Remember though that a board loaded in a turn takes on more of a W shape than a U shape.
I think the benfits are not so much in stored energy but in improved hydroelastics.
From what I have understood from this forum and around the web, surfboards does not act like a spring (apply force, and it will store it until released). Another thing to keep in mind in all this flexcrap, is the conditions under which these ideas are to work: Seawater weighs 1035kg/m3 and is liquid so it will squirt away when you push it ^-^, a surfer weights 80 kilos and a surfboard weights 2,5 kg. It moves under moderate speed and the force applied to the board during turns by most surfers are low at best. Within all the flappy arms and ineffiecent footmovements it is hard to argue that some twist/bend in the board on a microscale will have any noticable effect on the surfriding. People claim “oh man this board has amazing flex, its like i spring outta turns”. The videos I see around shows none of that. Just average surfing by average surfers. If the the flex ideas/ parabolic stringers have any merit, how come the best surfers still swear by a crappy blank with a sheet of 4ounce on top?
Adriano De Souza springs outta turns, but that is because his calves are 10lbs each
For 9 years, I rode a board with flex that was discernible. The effects on performance were noticeable.
Force = Mass x Acceleration
&
Centrifugal/Centripetal Acceleration is
where a = acceleration, v = velocity and r = radius
Earth’s gravitational acceleration is 32 ft/second per second. Times 3 = 96. So if my calculations are correct, a turn/cutback with a fixed radius of 10 feet at 21 mph will produce centrifugal/centripetal acceleration of 96 feet/second per second. Apparent rider and/or board weight will be 3 times greater than stationary (gravitational) weight. Centripetal Force will be 3 times greater than gravity – 3G.
Changing turn radius and/or velocity changes centripetal acceleration and “G-Force.” Changing mass also changes G-Force but has no effect on acceleration.
A lightweight performance shortboard with a single 4oz. deck flexes more than the average glassed surfboard.
Very flexible, yet breaks down quickly due to over-flexing.
Kinda like a skateboard tail loses its “pop” after repeated use.
**I encourage all surfers to ride a board with a parabolic stringer. **
The parabolic stringer does not feature a stringer running down the center of the board, but rather two on the rails to create a unique liveliness and flex for an unparalleled surfing experience.
Undeniably has a very springey burst of thrust out of every turn.
And yes, they are far more difficult to shape.
Thats why we do not see many coming out of shaping room.
Center stringers are easier to shape.
Most of the industry shys away from anything which requires extra work.
That explains the sea of clear squash-tails in the shops.
Most so-called shapers these day can’t even shape a triple-stringered sucessfully.
I enjoy the challenge.
This is surfing we’re talking here.
Practical experience trumps theory.
Don’t base your theories on videos.
Try one. You might be surprised.
Barry, does a center glue line effect flex much? If not, would a parabolic stringer blank with a center glue line be much easier to shape then one without? I’m not sure if it’s the lack of reference the parabolic blank has, or the stringers themselves?
Barry, have you seen any of the boards Dave Verner in Santa Cruz has built with some sort of stringer material, albeit straight lines and not curves, in the same general area? Wonder if you both may be on parellel trails. Just wondering and don’t know if Dave still builds them. Mike
No center stringer is actually easy to shape.
It’s the whole stringer right in the center of where you foil the rails is the kicker.
A glue line does have an effect on flex.
One down the center will have some effect, but very little.
I have glued many blanks without the wooden stringer.
Just multiple glue lines.
Pleasantly surprised how evenly the board flexed.
Flex is your friend.
Too much bad.
Too little bad.
Somewhere in the middle is what I’m after.
Ways of controling it for surfers of different heights and weight is the future.
And this is where your credibility begins to crumble. There are so many things wrong with this line of reasoning, among which is that it amounts to a recipe for monotony and stagnation (a good thing for an industry based on mass production and mass marketing).
Furthermore, if you think the boards “the best surfers swear by” are the gold standard for all surfers, ask yourself, Does everyone ride the same type waves the pros do? Does everyone make the same maneuvers the pros do? Does everyone surf the same conditions, with the same goals?
So true. When I shaped my fish tail recently, I couldn’t believe how much flex the tail had. I could feel it get stiffer with each successive layer of glass
Bingo. Amazing how willing people are to drink the kool-aid of modern advertising hype, without questioning, probing, investigating. I’m always shocked that people will come on here and give a negative review of a board they’ve never even ridden!
Again, right on. Despite all the posturing and hypothesizing, the true success of a surfboard design can only be determined by the guy out there catching waves on it. Everyone can sit around and shoot down the design ideas behind the board, but the guy riding it knows if its working for him, and if he’s catching waves and having fun and getting stoked (and not posing a threat to anyone and everyone around him - hah!) then I believe you cannot call the board a failure.
Cool stuff, though seems really labor intensive.
Have you tried to achieve the same results by eliminating the stringer altogether and using the laminate to control the flex/torsion?
Just curious, definitely appreciate the craftmanship that goes into those blanks though.
I like Mr. Snyder’s design. I have no doubt he has refined his design empirically to achieve a desired performance
Do not mistake scientific debate about the mechanism responsible for performance as posturing. I have seen more than one design presented using science as a hook to market or sell a concept. Do not espouse exotic science if you cannot substantiate it.
So far I do not feel Mr. Snyder has claimed esoteric scientific mechanisms for performance. He has given us enough to evaluate for ourselves. He has provided a link to his proposed mechanisms. However, nobody has to click that link.
I do not tell pro surfboard builders how to make surfboards. If I did, I would expect to be challenged. Expecting the same about scientific assertions is not unreasonable.
The gluing is a bit of work.
But I’m getting more efficient perfecting my process.
Once glued, it’s less work to shape than a triple stringer.
Too much flex is wasteful, and makes even great shapes flabby and soft. They just don’t perform. Even now a lot of surfboards are too floppy, too loose, and a lot of work has been done to try to get a more responsive quicker acting, surfboard. Thicker stringers stiffen but make heavier boards. Unidirectional milled wood, as Gordon Clark championed and US Blanks continue makes flex patterns far more certain, yet a lot of riders swear by peeled ply as a stringer. (Australians were brought up on cross section ply while the Americans have all been bought up on milled wood stringers.) Adding more glass does not work; the boards become stiff brittle feeling.
Stringers provide a crucial “I-beam” element to the “core” of a “foam sandwich.” They reinforce the ultimate strength of a surfboard by holding the top and bottom “skins” of the"foam sandwich" apart. Recently builder have tried to replace stringers with layers of fabrics, carbon fiber on the rails and etc. But none so far have acheived the feel of the consistant flex and feel of the stringer.
Before he died, I was fortunate to show Gordon Dwayne (Gordie) one of my first earlier stringer experiments. He is credited as being the first known to put a wooden stringer in some of the first Polyurethane blanks. He told me to"Keep it up." “You may be on to something” I was honored.
Most of mechanical explains used for surfboards are wrong, but they try to explain something really feel. Mechanical engineering can be really complex, even more when everyone have is theory and don’t know or accept basics LOL.
looks cool barry! seeing yours makes me want to do another one - gluing up that wedge is a bitch though!
why use a single thicker stick split at one end instead of two narrower ones (3/32")? having any issues with stringer poking up through the glass from getting stomped on if it is right under the back foot?
i think your direction with building this design on wide flat boards that tend to go fast in a straight line but have problems turing is better suited than on a performance shortboard that already turns easily.
another way to get flex out the tail is to cut out the stringer in the tail (and stagger the fiber layup) although this does not have the cool curved stringer
