I was not aware of that site. Bookmarked, Thanks.
I find the sound of an active ocean amazingly soothing. Great background sound. Very glad to not hear any background conversation, or hooting in that live feed.
I'm not watching it, but listening to it.
That particular fin is made from an~ 1/4 inch thick piece of western red cedar weighted atop 3 layers of 24oz woven roving saturated with epoxy resin, atop waxed glass. This fin panel was made middle of last year, and already produced two Unusual fins that performed well. But if one were to equate it with driving, it was like 25% more power and speed on tap and 50% less braking power and a steering wheel which turned the wheels farther with less driver input. A bit twitchy, thrilling but a bit hard to control as every turn was entered into with more knee buckling speed and I needed to choose completely different and unusual lines, or just hold on, kind of off kilter.
Woven roving is like fiberglass cloth, but each bundle of strands running in a grid like pattern/weave is about 3/16 inch wide instead of regular fiberglass cloth whose each individual bundle of strands might be 1/64" wide.
I think woven roving really needs to be saturated with polyester resin go more translucent. Epoxy does not have styrene, which might be required be dissolving the binders and get complete saturation, which help keep the cloth together when cutting and positioning it and saturating it. Fiberglas matt has lots of binders and is not compatible with epoxy, the woven roving does not advertise any binders, but I think they are there in a fraction of matt, and make complete saturation much much harder to achieve with epoxy
I used it, as it is 3 layers, versus about 25 to 30 layers one would need to achieve the same thickness with 3.7 oz 'E" cloth. Also I have only small unequal size scraps left of E cloth, but plenty of woven roving. 4 layers of WR proved way too stiff on previous fins. Stiff fins can be good, fast and crisp, but unforgiving, flexible feels more lively but can also feel squishy and slower, like under inflated tires especially with heavier more experienced surfers
I'd had this crazy Lucid Surfing dream about 6 weeks ago. i was on my 6'11" HWS but it was a single fin, but instead of a deep single fin in the middle of the tail of board, the single fin was on my toe side rail, and all other 4 fin box receptacles were empty.
3 open face pumps, where one turns off the bottom accelerating, then off the upper portion of the wave, aiming back at shore and 'down the hill', then turning back up the face, accelerating with each turn, on a righthand point break and I would accelerate so much I was able to lift off the wave face, and fly around on my board as high and far as I wanted to go. Good ole flying dreams, ...........can never have enough of them.
The fin was shaped like the one I just made. I was so enamored by the feeling of flying in that dream with the apparently magic fin when i awoke, I put to cardboard soon after waking, and stuck it in my board to figure out the correct looking size shape and location.
Multifinned surfboard rail fins, have a flat side on the inside. This makes perfect sense, ONLY from a manufacturing point of view, but rail fins that are equally foiled on both sides 50/50, like a single center fin, do not have a crisp projectioney feel when turning. They feel dull and listless.
So .... What should not work, does, and what should, seems to not, at least not very well, or not as well as that which should not, but does. Got it?
I made rail fins in the past with 80/20 and 70/30 foils, instead of 100/0 flat sided fins, and they worked OK, with a lot of power in the wave, but were not great when one needed to generate their own speed from a less powerful wave. I kept returning to flat sided rail fins.
The major fin manufacturers have offered fins with an 'inside' or cambered foil only in the last 15 years or so, and they get a few top riders to praise them publicly for a month or 4, but then one sees the same surfer riding other rail fins known to have a flat sided foil. There are not many adopters of rail fins withuot flat sides, the exception being quad fins, these trailing fins behind the main flat sided fins are often 80/20 or even 50/50. Some love em some hate em. There are a few twin fins with 50/50 foils on a board design called a fish, that are more like keels and these often have no toe in and no cant, and are a super fast design, that only a few seem to click with. I'm not one of them.
I was shown this one airfoiltools website and one particular airfoil, and the cross section made me realize I could actually achieve that, fairly accurately, since the inside of the fins foil was basically parallel with the centerline. So 'all' I had to do was add some thickness to the' flat side, and then foil and blend that to the flats and achieve a rail fin which makes hydrodynamic sense.
The white fin is a commercially available fin with an inside foil. It is sized for a thruster tri fin set up at about 4.5 inches deep, where my fin is more for a twin fin sized set up. Most twin fins are 5.25 to 5.625 inches deep. Mine is 6 inches deep, and more upright, higher aspect ratio, which has less drag than lower aspect ratio fins.
Rail fins are toe'd in, pointing to a spot on center of the board's nose or at some distance/point in front of the nose's tip. The angle of this tow in is pretty critical, but most point right at the boards nose tip, some are some point forward of that, and only a few actually cross the centerline before the actual end of the surfboard. More tow in means tigher turns but the board neeeds to be constantly moving from rail to rail /side to side, to generate speed in less powerful conditions and lt can look a little hyper and spastic underfoot, where as less toe in fins generally allow for less sharp turns and achieving speed without having to work as hard for it, but when the wave fac gets really steep the tail can be sucked up the face and require constant corrections to foot pressure and line taken, to not get sucked up and over. Lots of surfing is about being able to actually slow down/ stall. Less tow in is harder to stall and as a result the surfer can too easily outrun the powerful steeper portion of the wave, which is not as fun to do and certainly not as fun to observe.
Rail fins also are splayed outward, or have a cant angle, like a tire camber. In general More cant/splay can lead to a subjectively better feel during turns, less cant can lead to more accelleration through those turns. Most thrusters are 5 to 7 degrees of cant, most twin fins are about 3 to 4 degrees but there is no hard fast rule. Seems like so much surfboard/fin design is just accepted from the past without question. as such, only tiny incremental differences that cumulate over the years as boards are refined for a certain style of surfing for the rubber kneed youth with way too much free time and natural skill.
I'm questioning ALL traditional accepted fin design as I believe it is stuck in a rut of convention and tradition for the sake of tradition.
My particular fin system allows me the change splay/cant from 0 4 6 or 8 degrees, but I've not yet liked the feel of 0 or 4 degree with the fins I've tried. I can also move the fin a maximum of 1/2 inches foreward or backwards, though the latest fin I reduced this to 1/4 inch for a little more strength in the fin base, but I can always change it later if it needs to be farther forward or back. The fin system i use never really caught on as it is not super duper easy production friendly and is a bit heavy. The two main competing fin systems used worldwide, are not compatible. with it.
But the fin system I use is likely the easiest for the backyard fin builder to make their own strong based fins, and allows a lot of adjustment/ fine tuning..
Anyway, I was not able to achieve the super thin Drela AG10 foil at 100% thickness, because the cedar was not strong enough and the fin would be too floppy and flexible and weak, but the drela AG10 foil at 150%, I will estimate I scored a 99% in accuracy and precision of that expanded foil.
http://airfoiltools.com/airfoil/details?...-il#polars
In theory this fin, should have less drag and more lift. Less separation of flow at high angles of attack( turning harder), which means more speed/ drive, and perhaps precision. That lift of course, is not vertical lift, but mostly 'sideways' lift, and that tow in angle and splay and the water rushing up the waveface itself all contribute to the ability to attain speed travelling parallel to the beach. The board's bottom curves and rail shape and outline all of course have to work in conjunction with fin size, shape, foil, tow in, cant and orientation to the water flow and the rider positioning and ability.
But when it all comes together there is No feeling like it, and having created every unique piece of durable non disposable hardware in the chain, makes that feeling even more special.
There's nothing traditional about my board or fins, but I would be surprised if in ten years if off the rack surfboard fins look pretty much as they do now. On close inspection, flat insides aside, some of the foils are horrible!
I think surfboard fins in the relatively near future, should society persist and allow such activities to continue, will be slightly less total surface area, but deeper, more upright, slightly thicker with cambered foils with less tow in, and slightly farther back on the tail of the board, at least those ridden by the rubber kneed progressive youth pushing the barriers of how and where one can position themselves on, or above, a breaking wave's face.......
I could certainly be wrong, but I'll continue to believe the emperor is a naked fat douchebag. who need a kick in the temple, and if that pisses off the emperor's crysty yes men minions, so be it.
Got some glue drying on the new three foot LED wand's Bubinga Vbucker pot and switch cover. Cant decide what length to make its power cord, or where to have the wire exit the wand, so I opened another beer and closed the workshop door.
Perhaps the answer will come to me in a dream.
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