I want a more efficient way to test fin foils and shapes. I was thinking along the lines of a circular water bath with a variable speed flow-through pump for the power source at the opposite end of the testing area. The actual size of the bath needs to be large enough to eliminate any impact from the turbulence created by the bath sides. I am also thinking through the method of approach and the best way to measure the effects of the foil shape and overall design. There are many variables that need to be properly thought out. Of course all the testing in the world means nothing without live testing and determining the correlation between lab tests and field results. I am playing with fin templates and shapes and want a way to easily test hunches. (For those of you that see the HUGE holes in these two paragraphs please understand this is for the sake of a passion and should not be interpreted as anything that is going to be used in a commercial or scholastic endeavor.) So I am looking for anyones input and thoughts. I have purposely made this post very brief so as not to impact any creative thought that anyone would care to share with me. Thanks, Magoo p.s. Rich, I just got back into town and will send you that e-mail regarding the star fin.
I want a more efficient way to test fin foils and shapes. I was thinking > along the lines of a circular water bath with a variable speed > flow-through pump for the power source at the opposite end of the testing > area. The actual size of the bath needs to be large enough to eliminate > any impact from the turbulence created by the bath sides. I am also > thinking through the method of approach and the best way to measure the > effects of the foil shape and overall design.>>> There are many variables that need to be properly thought out. Of course > all the testing in the world means nothing without live testing and > determining the correlation between lab tests and field results. I am > playing with fin templates and shapes and want a way to easily test > hunches.>>> (For those of you that see the HUGE holes in these two paragraphs please > understand this is for the sake of a passion and should not be interpreted > as anything that is going to be used in a commercial or scholastic > endeavor.)>>> So I am looking for anyones input and thoughts. I have purposely made this > post very brief so as not to impact any creative thought that anyone would > care to share with me.>>> Thanks,>>> Magoo>>> p.s.>>> Rich,>>> I just got back into town and will send you that e-mail regarding the star > fin. Hey Magoo, Frankly I don’t think you can get done what your trying to do without some supreme effort and the ablity to get the water going at least 20 knots. No small trick my friend.A super long plastic tube in the shape of a “D” with place to insert the fin is the best thing I can think of. I can’t do any of that kind of fancy stuff. I just have to take what I’ve learned and listen to what people tell me about how what I make performs. I’ve got lots of ideas but the building process is time consuming when you want to make a good cosmentic presentation. I can turn stuff out much more quickly if I’m not worried about what it looks like but I’ve got so much to learn I need time to work many details out. I have my theories about how things work and why they act the way they do. Some of it is intuitive, some from my experience in aqualocomotion, and then from what I read and finally what I see in nature. I’ll look forward to you email. Good Surfin’, Rich
I want a more efficient way to test fin foils and shapes. I was thinking > along the lines of a circular water bath with a variable speed > flow-through pump for the power source at the opposite end of the testing > area. The actual size of the bath needs to be large enough to eliminate > any impact from the turbulence created by the bath sides. I am also > thinking through the method of approach and the best way to measure the > effects of the foil shape and overall design.>>> There are many variables that need to be properly thought out. Of course > all the testing in the world means nothing without live testing and > determining the correlation between lab tests and field results. I am > playing with fin templates and shapes and want a way to easily test > hunches.>>> (For those of you that see the HUGE holes in these two paragraphs please > understand this is for the sake of a passion and should not be interpreted > as anything that is going to be used in a commercial or scholastic > endeavor.)>>> So I am looking for anyones input and thoughts. I have purposely made this > post very brief so as not to impact any creative thought that anyone would > care to share with me.>>> Thanks,>>> Magoo>>> p.s.>>> Rich,>>> I just got back into town and will send you that e-mail regarding the star > fin. Way to go guy!Someone needs to research this stuff. Fins look about like they did 30 years ago…just a variation of a dolphins dorsal fin.I read a quote by George Greenough a little while ago and he said something to the affect that every rich pro surfer should be investing 30 grand a year in fin research or something like that. About 25 years ago a buddy of mine lost his fin and for the hell of it we laminated a 16 ounce Budweiser can on the board as a joke…guess what?it worked. Who Knows?
Hey Magoo,>>> Frankly I don’t think you can get done what your trying to do without some > supreme effort and the ablity to get the water going at least 20 knots. No > small trick my friend.A super long plastic tube in the shape of a > “D” with place to insert the fin is the best thing I can think > of.>>> I can’t do any of that kind of fancy stuff. I just have to take what I’ve > learned and listen to what people tell me about how what I make performs. > I’ve got lots of ideas but the building process is time consuming when you > want to make a good cosmentic presentation. I can turn stuff out much more > quickly if I’m not worried about what it looks like but I’ve got so much > to learn I need time to work many details out. In all reality, you most likely would need a bottom for the fin to attach to,as the water interacts there also. The fin would be needed to be torqued so that water would hit it from different angles too, this is when boards experience stall and cavitation. I did some really thick fins with pronounced cords, they were very unpredictible and would stall at extremely low speeds, with the tail of the board suddenly shifting to the side of the fin that had the most low pressure. At high speeds, like the bowl section at Honolua, the tail wold go completely out of it like a buckin’ bronco. Needless to say, with a tube throwin’ over your head and a rock somewhere dead ahead, this was something less than desirable for a fin characteristic. > I have my theories about how things work and why they act the way they do. > Some of it is intuitive, some from my experience in aqualocomotion, and > then from what I read and finally what I see in nature.>>> I’ll look forward to you email.>>> Good Surfin’, Rich
Way to go guy!Someone needs to research this stuff. Fins look about like > they did 30 years ago…just a variation of a dolphins dorsal fin.I read a > quote by George Greenough a little while ago and he said something to the > affect that every rich pro surfer should be investing 30 grand a year in > fin research or something like that. About 25 years ago a buddy of mine > lost his fin and for the hell of it we laminated a 16 ounce Budweiser can > on the board as a joke…guess what?it worked. Who Knows? Mike Hynson somehow got permission from the directors at Sea World in San Diego to take a temp. and measurements from one particular dolphin, Dolly. This was his design for Hynson Dolfin. It wasn’t very tall, had a thick cord, but it worked pretty darn good.
…It’s not that hard to make fins…Why don’t more of you push your creative buttons and try something… different??? …To me it seems, as a group, surfers think of themselves as progessive thinkers, pushing boundries, blah, blah, blah…When in reality if you put something UNUSUAL in front of them, not one in a hundred would say “Yeah, that looks like something I would try”… …I’ve got some things in my head that might work, or might not work…I’m definately gonna build them…Ride them…and see where it all leads me… ???Anyone out there on a similar trip???
…It’s not that hard to make fins…Why don’t more of you push your > creative buttons and try something… different???>>> …To me it seems, as a group, surfers think of themselves as progessive > thinkers, pushing boundries, blah, blah, blah…When in reality if you put > something UNUSUAL in front of them, not one in a hundred would say > “Yeah, that looks like something I would try”…>>> …I’ve got some things in my head that might work, or might not > work…I’m definately gonna build them…Ride them…and see where it all > leads me…>>> ???Anyone out there on a similar trip??? I am with you my friend…I want to see something really unique. Alternatives are out there if somebody had the time and money to pursue them. Go Forward, I’m to old to mess with it.
…It’s not that hard to make fins…Why don’t more of you push your creative buttons and try something… different??? …To me it seems, as a group, surfers think of themselves as progessive thinkers, pushing boundries, blah, blah, blah…When in reality if you put something UNUSUAL in front of them, not one in a hundred would say “Yeah, that looks like something I would try”… …I’ve got some things in my head that might work, or might not work…I’m definately gonna build them…Ride them…and see where it all leads me… ???Anyone out there on a similar trip??? Keep up the good work, Paul, “The shortest distance between two points is often by the longest route.” I cant imagine any other way. Its been 35+ years for me, wandering through the wilderness, questions answered and answers questioned, but never lost for long. Dale
Jim I have one of the original batch of Dolphin fins, it will be back in the water this summer on my 5’10 Hy a exercise in nostalgia for sure . grow Fins
Pinliner, What does the dolphin fin look like? Rich
…Nice fin, but with it as thick as it is, it is heavy…You can make a wooden version much lighter…In fact it woud float…Positive buoyancy, what a concept… Why do most surfers worry so much about light boards, then stick solid fiberglass fins on…I still can’t understand why surfboard fins are so heavy…Oh yeah…$$$… Paul
…Nice fin, but with it as thick as it is, it is heavy…You can make a > wooden version much lighter…In fact it woud float…Positive buoyancy, > what a concept…>>> Why do most surfers worry so much about light boards, then stick solid > fiberglass fins on…I still can’t understand why surfboard fins are so > heavy…Oh yeah…$$$…>>> Paul If you have the time and want to play around with a couple of fairly simple and inexpensive fin projects: … A very stiff, short, thick fin, like the Dolphin Fin… shape one out of EPS, laminate with glass and epoxy using only 25% of the normal amount for a solid fin. After curing, pour lacquer thinner onto the EPS interior, which will immediately dissolve. You
re left with a hollow, extremely light and bouyant, strong, cheap and reasonably durable fin...excellent for experimental purposes. Add just little bit more glass to the tip and leading edge areas, and youve got a permanent fin. Or just leave the EPS inside… your choice. The bases can even be made so the fin is removable. To feel something a bit closer to the real Dolphins fin (they do bend and twist), laminate a sheet of fiberglass to fit into your fin system, thin out the fin (without a foil) more than usual, so it increasingly flexes toward the tip (youll have to guess how much), using an industrial contact cement, attach a sheet of fine closed cell foam to each side, sand that to the proper thick foil, and finally add several more coats of contact adhesive (or a tool coating like Plasti-Dip) to entire fin to seal and smooth out the cell structure. Youre left with a flexible, light, bouyant, inexpensive, flesh-like, removable fin with which to experiment. If the flex isnt right, simply grind the closed cell foam sides off and add or remove fiberglass, etc. There are a great many more ways to learn about various fins and to feel different things… all with a minimum of effort and cost. Dale
Hey Magoo, I commend you upon your endeavor into the theoretical. Tank testing has been done for years at numerous universities around the world. Much of their experience has been documented and is available for review. From what I have read you can get a feel for the extremes of the design envelope in specific orientations. However, until you and several other test riders get out and ride a foil. You will end up with a very two dimensional study that does not necessarily equate to the real world. It may be in your best interest to start a test board with a removable fin system and a journal. Document conditions, riders, and various fin configurations and see if you can’t work out a spread sheet rating the differnet characteristics you intend to find. This is the method a number of shapers that we work with use to progress their theories. Red X always attempts to assist in any way we can to facilitate their studies and the progression of their theories.
…Nice fin, but with it as thick as it is, it is heavy…You can make a > wooden version much lighter…In fact it woud float…Positive buoyancy, > what a concept…>>> Why do most surfers worry so much about light boards, then stick solid > fiberglass fins on…I still can’t understand why surfboard fins are so > heavy…Oh yeah…$$$…>>> Paul Paul, I concure and it’s why I make fins that float. Good Surfin’, Rich
I commend you upon your endeavor into the theoretical. Tank testing has > been done for years at numerous universities around the world. Much of > their experience has been documented and is available for review. From > what I have read you can get a feel for the extremes of the design > envelope in specific orientations. However, until you and several other > test riders get out and ride a foil. You will end up with a very two > dimensional study that does not necessarily equate to the real world. It > may be in your best interest to start a test board with a removable fin > system and a journal. Document conditions, riders, and various fin > configurations and see if you can’t work out a spread sheet rating the > differnet characteristics you intend to find. This is the method a number > of shapers that we work with use to progress their theories. Red X always > attempts to assist in any way we can to facilitate their studies and the > progression of their theories. Thanks Tom, Your recommendation pretty much sums up my method of documentation. I appreciate the input. While in school I was doing some undergrad work measuring the O2 consumption of certain fish while ‘performing work’ – this is where I am getting the flow tank concept from (no original thought here!). Would you be able to direct me to any sites that have the academic results posted for review? No need to reinvent the wheel if someone has been down the road before. I enjoy the pursuit as much as the empirical work. I have to thank Herb for opening this door for me because his Superchargers got me on the testing kick – for those of you new to the site → they work great! I appreciate Jim and Dales input as well as everyone elses’ Thank you all. To Pauls’ point - What direction are you thinking of going? Your post makes me think of a bottom design that I saw that was supposed to eliminate fins due to channels and integral wing extensions. Final question: What happens as a fin gets longer? I’ve read some vauge information regarding ‘Drive increases’ but I would like to hear from someone who has created a longer fin and slammed it on a thruster or whatever. My frame of reference is the fin of a Tuna and the potential benefits of that design. Has the law of diminishing returns been addressed to such an extent that it is the reason for the homogeneity (sp?) in fins? Thanks again for the help Gents. Magoo
Thanks Tom,>>> Your recommendation pretty much sums up my method of documentation. I > appreciate the input. While in school I was doing some undergrad work > measuring the O2 consumption of certain fish while ‘performing work’ – > this is where I am getting the flow tank concept from (no original thought > here!).>>> Would you be able to direct me to any sites that have the academic results > posted for review? No need to reinvent the wheel if someone has been down > the road before. I enjoy the pursuit as much as the empirical work. I have > to thank Herb for opening this door for me because his Superchargers got > me on the testing kick – for those of you new to the site → they work > great!>>> I appreciate Jim and Dales input as well as everyone elses’ Thank you all.>>> To Pauls’ point - What direction are you thinking of going? Your post > makes me think of a bottom design that I saw that was supposed to > eliminate fins due to channels and integral wing extensions.>>> Final question:>>> What happens as a fin gets longer? I’ve read some vauge information > regarding ‘Drive increases’ but I would like to hear from someone who has > created a longer fin and slammed it on a thruster or whatever. My frame of > reference is the fin of a Tuna and the potential benefits of that design. > Has the law of diminishing returns been addressed to such an extent that > it is the reason for the homogeneity (sp?) in fins?>>> Thanks again for the help Gents.>>> Magoo Hey fin maniacs, I just finished the experimental thruster set for my new 7’9". The templates are my own and the central fin is different and slightly deeper than the rail fins. It’s a custom Natural Curves and Kalu did a super job with the shape! I’d like to post the photo for you guy to chew on for a while. What’s the procedure Swaylocks? Gone Surfin’, Rich P.S. I still don’t know what shape the dolphin fin is. Can anybody help?
To Pauls’ point - What direction are you thinking of going? Your post > makes me think of a bottom design that I saw that was supposed to > eliminate fins due to channels and integral wing extensions. …I’m thinking of a keel for my 12’er…Maybe a flex keel…>>> What happens as a fin gets longer? I’ve read some vauge information > regarding ‘Drive increases’ but I would like to hear from someone who has > created a longer fin and slammed it on a thruster or whatever. My frame of > reference is the fin of a Tuna and the potential benefits of that design. > Has the law of diminishing returns been addressed to such an extent that > it is the reason for the homogeneity (sp?) in fins? …Longer, rake, foil, flex…So many variables…I had the tuna thing in mind when I made some of my thicker base fins…9.5" high works well for me, given my size (6’4" x 200#) and my preference for single fins…I’m tellin’ you,the fuller foil makes a HUGE difference… Paul>>> Thanks again for the help Gents.>>> Magoo
…What input do you guys have regarding a more foiled fin???.. Paul
“My frame of reference is the fin of a Tuna and the potential benefits of that design. Has the law of diminishing returns been addressed to such an extent that it is the reason for the homogeneity (sp?) in fins?” Magoo, The Blue Fin tuna was George Greenoughs frame of reference, too... almost 40 years ago!! Give George a call, he loves to talk fins, and has learned quite a bit since the early 1960s: www.georgegreenough.com/ Dale
Magoo, More tasty food for thought: “…Up on Montecito Heights George Greenough is making carbon fiber spoons that sail so fast he’s taken to using metal for fins because it’s the only material that will survive the tremendous torional loads and not fatigue. Over at Project Design the loose knit Wave Delineation crew of Sam Foose, Chip Foose and Mr. Herzog secretly ponder aluminum honeycomb-centered carbon-fiber-sheathed helium bladder-filled boards. Not on this planet you say? Recollect that these same versatile guys make everything from Sex Wax to handformed automobiles; some of which just might be carbon fiber-bodied lighter than air gas-filled racing units.” An excerpt from “The Making Of The Modern Surfboard”, by C.R. Stecyk http://ewave.globalmax.com/history.html