http://www.dantomo.com/hydrofoils.html
Huh?
http://www.surfresearch.com.au/a_surfboard_dynamics.html#Lord%20:%20Planning%20Hulls
Supporting Info?
Marketing
Interesting…have to mull this. You will have to attract Mr. Casey to take a peruse. It appears he has little to do lately as he has been quite active hereabouts…Other than a lack of locomotion (upward flow on the wave face), I think this fits into what he has been preaching for years.
Not that I fully understand much of this either, but it is at best a gross oversimplification of the whole surfing dynamic.
Perhaps some breakthrough can be achieved by the application of calculus but I think its more fun to shape a few boards and try them. Too many variables to manage otherwise…
Without even looking at the links, I can pose the question: how will we find someone smarter than crafty?
I have a feeling perusing the links might give me a headache...
It’s been so long now since I fully studied up on this stuff in an academic manner, and after some years of study on Sways (Especially the “Concave for control” thread - which, by the way, after much reflection on my part, caused me to change my thoughts about “concaves” and lift.), and my own empirical experiments, I’d argue, to a large degree, what makes a surf board work, i.e., what we may call the “hydrodynamics” of surfboard function, is far more complicated than Bernellie’s (Sp?), or Venturi’s (Sp?) principles, and, to take the side of some of the more cynical Sway brethren, I’d say the link reads like another marketing ploy.
Sorry Crafty - Not much of an explanation of the link’s info, but my interpretation of the situation.
Does a planing craft not have to reach 20 knots before any hydrofoil effect will come into play? Does a paddle in surfboard reach 20 knots in “normal” conditions?
I cannot view anyone as “smart” when they can’t even spell a simple word like “planing”.
“Planning” is the act of making a plan.
Furthermore, the writing in that first linked page is on the level of a 3rd grader. More nonsense and gobbledygook from another self-appointed expert. Is he affiliated with surfscience.com?
My day off is almost over…
I have found the hole explanation of dans boards a little hard to put it all together. He states it as a brake through may be a personal and influential brake through but not in board design there are a few other shapers that use this equation too. I am just interested how he combines fighter jets, hydro equations and hatchets to make a board that from all feed back rides very well. But hey all good works of art and design don’t really have to be explained if they work. If you do the research Dan is a pretty impressive guy he rips in the water, grew up with surfing royalty and shapes boards that are trying all sorts not just the run of the mill. So keep up the good work Dan i think a few of us are just a little confused.
smells like some slick marketing again
if you just look at the look of the site
I'm definitely not smart enough to deal with this all (Maybe KC and Spindler are) but in this business it always seems to come down to something the color green going from point A to point B in some quantity or another at varying speeds.
never ceases to amaze me..
kind of like mixing chaos and string theory togethor to redefine the next blue jean
if you get what i mean..
My famous Physical Oceanography Prof and Chandler(GG) gave me the same lecture almost half a century apart in time but with the same effect..
Kinds of starts off like this.. (envision the twilight zone voice over as you read)
" Now imagine this, you are a particle of water flowing across a surface, now what would make you happy?"
Live aloha always…?
Pffffffttt. Right.
You seem to know DT very well crex. I am not exactly interested in his surfing ability or his surfing royalty, just interested in the 'engineering'. Maybe you can give him a shout and ask him to explain how the use of the equation improves his boards. I am particularly interested in how he derived the term "hydrodynamic-foil engineered planning hull" from the use of the equation.
At minimum, DT should simply provide the definitions to each of the variables in Lindsay's equation. It might be easier for some to digest.
PS - was hoping KC would chime in, I know for a fact he's smarter than me :) (thanks Mike!)
I’m probably dumber than dumb dumb when it comes to this stuff, but from my perfunctory readings of hydrodynamics I believethat in Bernoulli’s equation which states that a fluid’s velocity increases as area decreases, the area referred to was a tube or cylinder. The rudimentary drawings I have seen of his theory wold not apply at all to plan shape with decreases.
I’ve always been skeptical even of the Campbell Brothers diagram which shows water being compressed by the concaves (thus accelerating through the fin area). In my mind water will take the path of least resistance and thus would just move away from the board, move towards deeper water.
Sounds like marketing to me. I doubt dano is there in the shaping room with an egineer’s calculator, plugging numbers into that equation to get his templates. Cute idea though,
You are correct sir. http://en.wikipedia.org/wiki/Bernoulli's_principle
However, I think the reference is to Lindsay and I would still like to know what the variables in the equation are. I wish I had access to the book.
Nonetheless, if the variables in the equation are not available for public consumption, I would state that more parallel running outline (as opposed to curvy) is a decades old approach to surfboard design, ie Lis fish. I just did not realize there was an equation that described what is happening. Curious minds would still like to know.
Hell…I’m not even smart enough to be allowed to post on this thread.
Oh well…maybe next time. 
It’s not bournelli…but it does tie in to Simmon’s reduction in tail block to improve release and reduce eddy.
Hasn’t Griffin alluded to smooth curve reduction married with rocker/wide point to improve release out the back and therefore increase forward momentum?
The pictures post of people surfing the Tomo’s make the board look like it works.
The fins are totally nuts.
Yes, but, Substituting the harmonic expressions of φ, φ′ and η in the boundary
conditions and retaining only first-order terms (with respect to a, C ,
and C ′ ) leads to the relations
(8) C k = iaω, C ′ k =
−ia(ω − kv)
and
(9) ρ (ga + iC ω) = ρ ′
No wait, that’s not what I meant to say. I meant to say was-
The situation could be compared to number theory, which is reputed for
the contrast between the simple statements of some of its problems and the
enormous difficulty of their solution. The parallel becomes even stronger
if we note that some nineteenth-century questions on hydrodynamic
stability, for example the stability of viscous flow in circular pipes or the
stability of viscous flow past obstacles are yet to be answered, and that
the few available answers to such questions were obtained at the price of
considerable mathematical efforts. This long persistence of basic questions
of fluid mechanics is the more striking because in physics questions tend
to change faster than their answers.
The last sentence is key to understanding and misunderstanding all the theories of fluid dynamics.
This thread is contraband.
That is all.