What advantages would there be to a fin that could optimize its angle of attack by moving? That`s easy: $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
Sta, What's your theory?
Alamode? Too rich? How about rainbow sherbet? Because I have been about this task for a while fin making and assorted tasks of a waterman since the mid '60s, in my original post I appealed to the creative to indulge themselves in the conception of a fin system that will allow the surfboard’s bottom and rail configuration to work at their maximum. Result-- The responses varied in tone and humor: 1. Do your homework. (That’s what this tread is about, admittedly there is always more.) 2. Learn from the past (Sound advice.) 3. Talk to George. (I want to -- and I may even have his phone number, yikes!) 4. Pertinent info about George’s preferences in surf-craft and confirmation of my contention in the original post that in fact -- others have learned more is less & less is more. (encouraging news) 5. Links on wing design drag and lift performance (Valuable information) 6. Someone was offended (No offense intended. When we agree to disagree we make the first step toward progress.) 7. Artistic encouragement given (Thanx Brah!) 8. There are many levels of fun (I won’t touch that one.) 9. Agreement that there may be something to be gained by looking closely at the tuna’s ways of aqua-locomotion, and antithetically, don’t look at how fish get where they’re going. Cod, smelt, what’s the difference? (At the other end of the scale, there is some difference, though slightly, between a Hippo and a Saltwater croc. and are they dangerous! Ignoring nature is as well.) 10. Encouragement (A welcome beacon of hope, Thanx!) 11. Robofish search proved uneventful. 12. Why don't these so-called fin designers check into something other than "fins"? (Possibly a coke bottle is my answer, thus I will live in disappointment forever. But if not in the sea and sky, where shall I look for answers?) 13. Look hard at the traditional approach. (Sound advice,) 14. Imitations of life are foolishness. (A scary thought when every invention of man has this as a principle driving force.) 15. Abandon research for 10 years. (Sorry, can’t do that, I may be dead by then.) 16. Facilitate mechanical fin retraction and angle adjustment. (Out of my scope, but with computers many things thought impossible become quite easy) 17. No takers? No one stepped up to the plate – if not rainbow sherbet how about rocky road or butterscotch? Come-on – What would your version be? Conclusion: I took the same set-up I've surfed on my 8’0x21.25” Freeline platter and 8’8”x21.25” B.K fun-board yesterday and though it may need a little more fin area to hold a line well in the soup, in the green water of shoulder to head high surf my 9’5”x17.5”x22.5”x14.25”x 2.875” Junod (great board!) felt like it was on an oil slick, paddled like a rocket, trim response was super, drove out of some steep walls, had flat speed to burn and that underwater late take off was sick -- Damn! what a good session! The set-up? Rail fins are 6.0” of George’s Stage IV template -- symmetrically (tuna-tail) foiled of an epoxy fiberglass lamination with a very slight amount of tip flex, and are set at 3+ degrees. The center fin, which is the same profile as a Dolphin dorsal (fish-foiled) and is 3.5” is set all the way back in the center box for stability. I have the next stage in the works, any suggestions? I know, some guys will try anything, but what the hell, how else do you learn except by experiment? How am I doing? Give me your best shot! No Worries, Rich
Greenough`s PaddleFin is an active stabilizer, i.e. the wider, upper half of the blade torques with turning force and water flow. Rich- George`s phone number is 011 61 266 877090. Try calling between 2 p.m. and 4 p.m (our time- PST).
Hey Dale, I'll bet that'll cost an arm and a leg, or am I wrong? No Worries, Rich
I'm looking forward to what you learn from talking with George.
Rich, I disconnected my long distance phone service several years ago, and just use phone cards. We`ve had significant savings. Cosco`s phone cards have a consistently good reputation. In my area, I buy the "USA Direct- No Connect Charge". I usually get the $5.00 ones which offer 100 minutes in the US- a $10.00 card gets you 200 minutes. If I call NSW Australia, the cost is about 12 cents a minute. You do have to careful- one of my recent calls to Greg Webber in Australia was over $2.24 a minute... the connection was to his cell phone! Anyway, if you leave a message and George calls you back, he uses a block of purchased phone time and only pays about $3.00 for every 30 minutes to the US. Then after a certain amount of time has elapsed, he gets to talk awhile for free! The Aussies have it going on with their telecommunications system! If you use credit cards, the best phone minutes deal I`ve ever seen is offered by (www.onesuite.com). It was recommended to me by one of the editors at Rolling Stone Magazine in New York. http://www.onesuite.com/
Is the optimal fin design to have no fins at all? A flexable board that bends like a snow ski and turns with the change in its rocker and rails.
How closely should we look to nature for a guide to designing anything can come down to finding moments in which the greatest parallels in dynamics exist. Being dreamily guided by nature can be useful, despite limited direct translations of shape, in that during phases of design thought in this mode, a feeling for the dynamics can be attained. We are neither a fish nor a submarine, neither bird or jet plane but it sure is easier to identify with some of the movements of the living things. So by 'feeling' the dynamics of a certain moment of fin action (the whip of the tuna fin and the quick pump of a surfboard fin) the universal relationships part of the brain can be utilised to fuel the design part of the brain. There is a chunk of brain matter that seems to have a way of putting things together in a new way to make a breakthrough. This thread highlights the contrasts in thinking, but I would like to see if ideas could be grabbed and followed along towards an actual creation. Are any of you in a position to follow this trippy little project, by making fins in new ways to allow for the flex that is yet to be explored. My experiments so far have been to try every shape of fin from forward pointing with aeroplane wing planshape, to parabolic upright, to very raked , to semi circular, to full keel. I copied a Skip Fry fish 10 or so years ago for Derek Hynd, and after riding the board that he loved (the one I was to use as a guide) I wanted to put the keels on but have them attached at the front of the base only. I foiled the things myself and got them flexy enough to get about 10mm of flex with reasonable thumb pressure, over the 9" or 10" of their length. After one bottom turn or two they ripped off, due to the flimsy roving and glass work at the front. However, one turn was enough to show me the link that occured between water and fin when the fin flexed to match in with the arc of the turn. Instead of getting the fins remounted better to fully test the concept, hynd insultingly decided to grind them off and put a normal set of tri fins on them. (Kind of shattered me, only spent 3 hours on the shape from a blank and probably an hour on each fin with blocks and all!) So next tests were flexing keels of varying lengths and height...will continue
Continued....(it's 1am so had to make some tea) So I found that the longer shallower keels never achieved the hold of the same surface area of a more upright fin(obvious I know, but it is more useful data for the brain if it actually has the sensations of the two fin types in the mind not just the theory). So then I started flexing them in the same plane as the stringer but from nose to tail. Got heaps more hold, yet never as much as the deeper standard fin shape. Gave one to Bryce Ellis (top 16 in the late 80s and early 90s) about 5 years ago. He was living at Angourie at the same time and he still claims them as something worth following up. Patented (provisional only)the idea of the fixed front and flexing trailing edge..had to let it lapse, due to no funds to go worldwide, and FCS didn't see any merit in the idea. Speed fins got onto it eventually (I know that others have used this flex type when attached to a deep raking fin, but there is a distinct difference when the fin buts up to the bottom of the board yet still flexes) SO...(sorry to take so long) ended up combining the standard upright fin as we usually see it (but more greenoughy) with a 7" keel. Imagine the two fin templates in your hands, and put both of their front edges in line with eachother. The combo of the two is great. I have done longboard, twin and tri fin versions, but I saw a nice photo in a previous thread of someone elses close to identical version. Can this crew please contact me. Did you do this independently? To come back to the nature or not issue, this combo seems to combine a bit of both man and natures tricks, but I think there is much more to do yet. To Tony who's on the right track and to halcyon for initiating this and also sensing the potential, who wants to try one of what I am doing? I have Phil Way of fluid foils right now doing 10 or so 9" versions. email me if anyone is interested. I've ridden the only longboard fin I have made so far at Spookies at Angourie, and it felt really nice. Hold and smoothness with a continuation of the link between board and fin, and a stability in the 'yaw' axis. I can imagine forward pointing and tip trailing fins, both pulling into the turn to harness more energy while matching into the arc of the turn to decrease the drag that has always come from 'scraping' stiff fins through the water. Add some slight tip curve to the side fins, which can flex to almost straight when under full load, and some eliptical holes right through the upright parts (my brother Johns' new idea) and you've got some trippy stuff happening. Greg W