Flex

[hart]

Why is it we don't see these design elements in wider use?

Hey Joe,

One reason may be the polarised nature of the responses that we have seen here..

I am so into Flexman's way of thinking, yet at the same time can see willli's points-of-view clearly.

So much so that I can see both their opinions in my work on a daily basis.

In my view, the market is led from above..it is led by the surfer. If a surfer wants flex..they will seek it out. Enter Bryan Jackson and Surfhorn.

And yes, all boards contain flex to a degree. So it seems to me that we are discussing an extremely incremental thing..one small element in the complexity of surfboard design.

hart.

PS

They guys who ordered the Flextails you saw reckon they are the best boards that they have ever surfed..and they were both consevative, traditionalist type people.

I reckon that if I had done them something that "I" had wanted..like a contemporary Thruster..they would have said the same thing.

[Flexman]

.

[schwammenmaschine]

i am coming at this from a bodyboarders point of veiw. but, i have ridden my entire short life and i have discovered that stiff boards with lessflex over all generate more speed and have a greater"drive". while a board with the same template andno stringers to make it stiffer will be a bit sluggish but will be able to have more control in the turns.

every one on this site is so eliquent this is a big change from the forums i normally frequent

[willli]

Hi Flexman,
You're just the person I had in mind when I noted that some on this forum actually know how to manipulate weave and do proper resin loading with flex in mind. And the knowledge you have is hard won through years of experience working with these materials. It is subjective (based on your experience) and empirical (learned through observation).
I've been maintaining flex=shape changing, and the energy a material "stores" is nothing more than necessary to return to its original shape, and it is the dynamic adjustment to hydrodynamic forces that empowers flex. i've often wondered about the shape the bottom of Velo assumes driving at optimum speed. I've wondered if its vee in front, concave through the middle, and vee out the tail with the rocker relatively flat. Do you know?
I won't ask the same question of mats cos they're off the chart in terms of delivering flex and go a long way toward putting the flex dynamic in the hands of the rider instead of depending on the response limits of a semi-rigid plastic.

[Flexman]

.

[hart]

I have a spoon built from Greenough's specifications.

Boyd (Kelnar) verified it at PC's wake. It was built by Warren Pfeiffer and Mark Denovan in Sydney. Peter gave it to me for work undertaken.

Thanks, once more PC.

It was styled after the black and white boards that we see in "Crystal Voyager"..which post-dated the velo.

As Flexman said..it is all 'belly' in the nose. All release. Rail line off the bottom is high, very high..for the front one third.

Then it starts to go straight..all the way to the tail..getting straighter with every millimetre..like a bloody hyperbola, like those things they made us look at in high school maths..like the graphs.

So glad I paid attention, especially now.

Curves first, then straighter curves, getting ever straighter still but never getting 'totally' straight..all the way to the tail.

And..no concave whatsoever.. Anywhere.. Like zero..zilch..nothing.

Yet Greenough's bottom turns are THE FASTEST things that I have ever seen in the water..ever. Who needs concs for speed?

Concaves are a modern phenomenom that compensate for the inherent inadequacy of contemporary design to adequately address the function of wave action. Concaves are a reactionary device.

Concaves are a result of rigidity..the result of an absence of flex..And the straight(er) bottom line that preceeds it.

Greenough was proactive in his thinking and his design.

Myself, on the other hand..continues to try and solve problems.

Many of which, are self inflicted.



hart

PS

And with thanks to Greg Webber, I use concaves every day of my (modern) working life.

[surfhorn]

Boards sitting on the glassing rack can twist as the resin starts going off due to the heat generated by the catalyzed resin. I'm sure this can be avoided by varying the amount of catalyzing agent used....thus reducing heat.

But, then again, I don't pay that much attention any more ...it would drive me crazy. I just ride the board wihtout worrying about it.

[nwdude]

perhaps the reason velo is so fast, is that it is a displacement hull - in sailboat lingo, a boat's top theoretical speed is directly related to its water line length - the longer the hull, the greater the speed that can be obtained whereas in a planning hull ( ie. modern surfbords ) the top speed is more limited by friction and the forces that drive it ( i'm fuzzy on this part ) i think all things being equal in a planning hull, the shorter design wins the speed contest - maybe that's why us kneelos are so fast !

[Bryan Jackson]

The question is, although a flex spoon may be referred to as a "displacement hull", is it really?

My understanding is that a displacement hull actually "displaces" the water! Think of an ocean liner or aircraft carrier plowing through the ocean. That is a true displacement hull .

Although when static or moving slowly through the water a kneeboard spoon may look and/or act as a displacement hull, once up to speed and in action (i.e., flying down the face of the wave), it sure looks like its planing to me!

Therefore, to be technically correct I don't think it should be called a "displacement hull" (but that is the name which it was originally given and which has stuck).

(NOTE: see my latest post on the "20 interesting questions..." thread as to why Greenough/Velo was so fast.)

[hart]

What made Velo such a challenge to ride was that it had untold gears. Because of its deep displacement hull, it never peaked out.

No matter how fast you were going, you could bury the forward rail into a bottom turn and break the fin out, and it would jump into the next gear.

George Greenough

Not all boards displace..

But Greenough used displacement to let his "forward rail" enter. This would be impossible if it didn't displace water in doing so.

But, not all boards displace..they sit on top of the water and only ever plane.

Greenough used displacement as well as planing in his principles..he understood them both.

It has been mentioned by many others on various other threads as to whether boards travel "over" or "through" the water.

In my view, they do both..when planing, it is "over"..when it displaces it is "through".

And Greenough was onto it long before anyone else.

Just like Flexman said..

"If we ignore the past, we are bound to repeat its mistakes"

Too true.

hart

[Bryan Jackson]

Well if that's your definition of a "displacement hull" - that at some point the rail (forward, side, or back) "enters" the water - then pretty much 100% of all surfboards are effectively displacement hulls since any board can "bury" its rail .

Seems like a rather loose and sloppy definition to me, one of little use in defining a flex board and/or its dynamics .

[hart]

If I were to only consider kneeboards, then I can safely say "not all boards displace...."

Standups are a totally different creation in context to my post.

Modern (standup) surfboards are down to 1 7/8" thick. Most boards shaped would peak around 2 1/4"..2 3/8" max.

To order something 2 1/2" would generally have the shaper recommending a mini-mal..and subsequently, the guy around the corner.

And another thread altogether.

Kneeboards however, remain full volume creatures..well, foam ones anyway..(so now, I should qualify spoons as well). A lot of guys (sorry, kneeboarders) are still surfing around 3" thick.

I have seen kneeboard surfers commence a turn and not "enter". I see it all the time.

The reaction is a turn that doesn't engage a rail. It resembles a tail-type turn, where you are pushed into a direction that your fins..or rails determin.

The board is in fact, dictating your type of turn, the way you surf..and not the surfer.

I want to see a rail load. I want to see a surfer (read kneeboarder) lead his board into a turn thru body positioning and an empathy of style.

Because when I do, I will see a surfer that generates drive and speed from a manoeuvre and creates accelleration as a result. Just like watching Greenough surf.

At no time however, did I attempt to define the principle of displacement hulls..nor attempt to draw analogies between ocean liners and surfboards.

And most pertainately, was at no time attempting to definine the dynamics of a flexible board or flex in general.

Because I will leave that to guys like Greenough. I am far too inexperienced.

Suffice to say, if you want to surf anywhere other than on top of the water..then you must displace water to do so.

And that..very simply, was my one and only point.

hart

[willli]

Anyone who has spent significant time around recreational powerboats would describe planing somewhat like this: initially the boat is at rest, displacing water equal to its own weight. as power is applied the bow pushes water creating a wave in front of it. as power is increased the boat climbs this wave and with increasing speed passes over it. there will be a transition, easily felt, where the boat changes trim and leaps forward, now drafting less, moving with far less friction (planing) and the operator can throttle back to a comfortable rpm and speed for the surface conditions. The wave (wake) now created by the boat appears to eminate from the back third.
Even a surfboard pushes a small wave in front of it as the surfer starts paddling, and leaves a very definite wake as it moves, so even planing is a form of displacement. The "displacement hull" has no hope of ever planing and that fact is central to its design but if you looked at modern racing sailboats (displacement hulls) at speed you would swear they were planing toward you, but like an iceberg, the part you can't see is most important. Modern sailboats are hybrids, owning both planing features and displacement features and the "keel" problem keeping them displaced solved with multi-hulls, which do plane.

[crox]

Kneeboards however, remain full volume creatures..well, foam ones anyway..(so now, I should qualify spoons as well). A lot of guys (sorry, kneeboarders) are still surfing around 3" thick.

I have seen kneeboard surfers commence a turn and not "enter". I see it all the time.

The reaction is a turn that doesn't engage a rail. It resembles a tail-type turn, where you are pushed into a direction that your fins..or rails determin.

The board is in fact, dictating your type of turn, the way you surf..and not the surfer.

I want to see a rail load. I want to see a surfer (read kneeboarder) lead his board into a turn thru body positioning and an empathy of style.

Spot on Bruce

[surfhorn]

Yeah, Bruce. I love the feeling of loading up a KB rail and springing out of a turn.

Sine the 1970's I've been running a rounded V in the bottom of the nose of all my KBs...and turned the rails up so as not to catch water on late drops. The trick has been to find the sweet spot where the rail shape turns from rolled up to a harder shape to grab water. That transition spot can be tricky.

I've never thought of this as a displacement hull but, rather, just a simple boat hull. This was necessary due to the fact that I came from the single fin KB school (as opposed to the Fish school - riding on the tail). My single fins rode from more of the middle of the board. At 4'10" - 5'2" there wasn't much board to play with and the nose rails caught very quickly if not shaped properly.

I was fortunate to be a team rider at Freeline and John had a very liberal trade-in policy; I've ridden boards once and then stuck them on the sales rack and had another board in a couple of days. But that was back in the 70s-80s and a lot of this was pure experimentation.

Fortunately, we have had decades of time to try out various design changes. Now this site has raised the bar even higher. All KBers can only benefit from this discourse. I thought my days of KB experimentaion were over and then along comes KSUSA.org and all the wonderful posts from the world's KBing elite.

Now, if I could only quit my day gig and just KB............