Hi There! Lately i spend many hours looking at all the possible outlines, rockers, concaves, laminations, fin set ups etc etc and I came to the conclusion that even a frontdoor would take off on a wave. Now the point is that all shapers have all their personal theories about all those hydrodynamic aspects of surfboards but, do anyone have ever demonstrate it scientifically that his theory is right? I've only found a research about the effect of flex on a board here posted on sway (and still at the beginning) but i've never found any scientific literature about concaves, rockers etc etc.Does exist any engeneering under surfboard making?
I think there was a PhD thesis written on fins and angles of attack. Maybe someone will post up a link to it. I had a look through it, looked very good, lots of flow moddeling and lab experiments.
Can't remember the conclusion though.
Look at it this way fishbone, you don’t use your harley sportster on the dirt bike track. You don’t drive on snow tires often in the florida keys. Your fishing for gems and nuggets too broadly. My point is, who is surfing that wave? A 300 lb kahuna in the gulf of mex or a 100 lb japanese at pipe? Is there any engineering involved in surfboard design and construction? What an insult and wow does that question piss me off. So what, it’s a public forum and the short answer is obviously yes. Oh I said it. Now what? Tell the wise members here what you really need because believe it or not they might try to help you in spite of yourself.
The board and rider must suit that wave. Add to that the fact that the wave is never the same twice and you begin to engineer on your own, hopefully. There are some very experienced people reading your question, engineers and field testers wrapped up in one. Get more specific.
I think fishbone is just looking for a "standard curve" so to speak.
The flex thread was a good example of good science which generated some standard values. You had an experiment where most of the variables were eliminated, bar one: flex>>>> same guy (same weight), same distance from the two supporting fulcrums etc
What that experiment generated was a standard set of values. And it made it possible to quantitavely compare one aspect of two boards in the same set of conditions. When you know the actuall value of the difference between two boards, it takes a bit of subjectivity out of surfing and replaces it with a number....so to speak.
You may want to look at Lindsey Lord's book which was Bob Simmons inspiration.
http://e-j-m.com/lord-book.html
There's also
http://users.tpg.com.au/users/mpaine/thesis.html
http://www.rodndtube.com/surf/info/Hydrodynamics.shtml
http://idisk.mac.com/mpaineau-Public/paine_surf_thesis1974.pdf
seems like fishbone is looking for “evidence base” of aspect of modern surfboard design theory. i don’t think that any scientific study could ever satisfy all of variables. surfing is such a dynamic activity. it is affected by wind, tide, swell, period, bottom contours. on top of that there’s the riders skill, experience, weight and height, approach, etc. finally there is the board.
any scientific study would have to test various variable under the same or similar conditions over a period of time to be able to gather enough data to create a thesis. the chances that any significant research of the kind takes place, or even receives the necessary funding, is pretty slim.
that is also the beauty of it. you can do your own experimentation and spend your entire life tweaking on what works best for you. you’ll never find something that will be perfect forever because we age and we progress.
A good place to start to study boards from a scientific perspective is to study them from the board out. What I mean is, this kind of experimentation should start with the use of sensors on and in the boards themselves to provide starting data from which analysis can begin. Devices that measure the strength of and direction of forces, and instruments that measure the direction and velocity of the flow of water under and around the board, and can show us how velocity changes and direction changes, are what I think we need most. From there, we can use simple physics to explain what we see and feel, and make predictions about where we need to go from here.
A lot has been discovered “the hard way” up to this point… and a LOT of credit has to be given to those creative, intuitive, risk-taking minds, and the talented hands that were skilled enough to turn their visions into surfboards. Surfboards today are pretty amazing pieces of equipment if you think about it.
The question becomes, where do we go from here?
"Where do we go from here?" is a great question.
As a beginner I can attest to the frustration of "where do I begin?".
I won't pretend to have learned much but what I am learning is exactly how little I know.
I can understand fishbones question and I can also understand dlocks resentment of that question.
To an "untrained eye" it doesn't look like much goes into a surfboard. Its an oblong piece of plastic. Big deal. The ones from thirty years ago don't LOOK much different from the ones on the shelves today unless you know what you're looking at.
To someone who knows better the differences are infinite.
What's frustrating is trying to figure out how to get from being someone that doesn't know to someone that does.
You can't take a night class on how to design a surfboard.
All you can do is dive in. Ask questions. Sometimes you'll get an answer sometimes you'll get abuse. So you ask again. You try things. You ask again. You try again. Some guys like to share what they've learned. Others like to protect their trade secrets.
Its pretty easy to copy what someone else has figured out or what has developed over the years. Understanding why the thing you copied is the way that it is can be tricky. So you study it, you tweak it, you make assumptions, you share your thoughts and sometimes you get more abuse. More often you get good advice.
It reminds me of stories I've read about the master swordsman of ancient Japan. If you asked one to teach you he would curse you and chase you away. If you asked again he would do the same. If you asked again and again and again, absorbing his abuse each time, eventually he would see that you were committed to learn and he would accept you as a student.
Teach me Samurai...
In light of the fact that many designs work in many conditions, you do have a point.
The precise narrowing of any particular design to fit specific parameters is often based on factors that don't necessarily apply to Average Joe in average real world conditions. I.E. what board was the winner of this year's world cup on? What board(s) is your peer group riding? What boards are featured in this month's magazine design guide? Needless to say, little 'science' is involved when it comes to the fashion industry that surfing has become.
Do your own simple experiments... stick a spoon in the water coming out of your kitchen faucet. Make a scale model and rock it fore/aft and side to side. Visualize the effect of rocker, vee and belly. Take the scale model and drag it by a string in a test tank. Put on a mask and snorkel and watch boards being ridden from underwater.
Better yet, build a few boards and ride 'em, cowboy. http://www.youtube.com/watch?v=7WeSHxrFNl0
I’ve ridden flat boards and they aren’t the easiest things to ride. You need to keep the nose up and they are often only partially in the wave.
My neighbor is a retired professor. He specialized in hydrodynamics and is credited with designing the SWATH hull. We’ve discussed surfboard and canoe designs and he said it’s nearly impossible to create a perfect design because of all the variables. Wave size, shape, water turbulence like wind chop, and many other things make one design better than another for any given set of variables. Even for canoes there are a lot of things you’d want for a surfing canoe that you don’t want on a racing canoe.
I think you can make a really good design for a specific break when it’s a certain size, but as the wave size changes that design may not be the best.
I’d look at the relationship between the rocker and the outline to fit the waves first, then tailor the profile and rails to personal preference. All of this is dependent on the wave shape and energy it has. The rocker of my BK semi gun has is totally different than my small wave short board and that’s totally different from my longboard. Seems like the big wave boards have a bit more nose rocker and a bit less tail rocker, the short boards may be a bit more balanced, and the longboards can have more tail rocker. Same for the thickness profile and rail shapes. The longboard has nearly 50/50 rails in the center, my other boards are more down rail, and others are all tucked under
So at the end of the day every wave wants a different surfboard.Thats all what i wanted to know.