My last surf session was on a 5’8"x20-3/8"x2-7/16" twin keeled fish. Been messing with them lately.
Just the brief version: already doing boards with off-axis lay-ups and super flexy foam with awesome results in performance shortboards. All hand built. Ok, that’s already been done, and I’ve taken it to more versions and have not plateaued yet (the limiting factor is time.)
IF I could dream, I would explore two strands of surfboard research and bring them together. First would be more detailed FEA using programs similar to what the America’s Cup designers have been using. I would push the Finite Element Analysis further, not just modelling the structure/mass of the board but ALSO the wave. Unlike flat water’s “bobbing water” and wind gusts sailing vessels deal with, waves are VERY challenging to model on the computer. This is because the face of the wave is curved, dynamic AND accelerating. As a visual tool look at some ping pong balls floating in a perfect grid on the water, 1 foot apart. As the wave approaches, peaks up and crests, the spacing of the ping pong balls accelerate away from one-another. This has not been explicitly tapped into by current board designs, at least not intentionally. A board could be “adjusted” for a particular “angle” or attitude for optimal function at that moment…
The second thing would be to incorporate SMA’s into an ultra-lightweight aerostructure. Shape Memory Alloys could be somehow embedded into a good baseline board shape. The board would probably be hollow, even valved, and the SMA’s would be controlled by a miniaturized on-board programmable processor. By varying voltage through the wireframe of the board, the shape and flex of the board could be changed. The wireframe would dual purpose as tensile members and shape changing. A basic example would be SMA bands embedded laterally, likely in pairs, so bottom contour could go from convex belly to concave(s) in milliseconds. Also imagine a board “puffed up” for easier paddle then shrunk down for tight surfing once you’re going…
What I just said ^^^ would be in the millions of $$$, but you said no limit… (I can provide some basic layups for the more realistic answer I gave, ha)
Hi! Been wanting to meet with you just to talk shop, time is my problem, I really dig your hands-on real deal approach, bravo! “What makes a surfboard go?” OH MAN… (smart aleck response: Waves, Gravity, Muscle.) LOL Actually, the typical board is static, it needs those external elements to go. To make a board go WELL, now that’s a life-long journey, even with the collective brain trust here on Swaylock’s. For some, it doesn’t matter, “I just wanna get a couple waves before sunset…” vs where things might matter a little more, “What if we changed the foam and glassed a load strip in it?” Other than that, I too am shaking my head… …let me just summarize with “Anything in the board’s character to work with waves, gravity and muscle in a way in which the rider likes.”
Great question. I think a LOT about Flex in Surfboards… …I’ve had arguments with reputable shapers, saying “boards don’t flex” but my training tells me otherwise, in fact EVERYTHING is a spring, even a rock, even water, especially MOVING water (or You, moving across water (a relative intertial frame shift for discussion’s sake.)) First, and I don’t mean to be a smart ass, but nomenclature is Longitudinal for lengthwise flex, also called Straight Bending. Bending from rail-to-rail is Lateral, or I’ve heard some call it “curling” on surfboards is less understood (until the introduction of “parabolic,” or “perimetric” stringers.) The twist, as mentioned is Torsion. All 3 bending modes are important, and I have tested and validated what I thought was desireable (THANK GOD FOR 1" WIDE CARBON GRAPHITE TAPE.) I’ve placed tape in various directions on boards, to completely/partially lock out discrete bending modes. eg. glass on 1" carbon tape at 45 deg X’s on a board to lock out Torsion. (90 for Lateral, etc.) This is where I got in a LOT of HOT water with some kneeboard builders, firmly convinced the twist is what made their boards go, but in general I’ve found Torsion to be the enemy. Surfboards (thin ones especially,) will bog down with they twist too much. Surfboards are glass in such a way to leave them wide open for too much torsion, the cloth comes off the rolls at 0/90 since the beginning. The 0 deg, or “warp direction” is good for Longitudinal control (of bending.) (90 or “fill direction” is good for Lateral control.) Most boards do not have cloth at 45 degrees, thus are wide open to twist and non-immediate rebound. You will benefit with “off axis” glassing, that’s been done for decades, I’ve met success with it, but be careful, if you do -20 deg with one pull, it is suggested to do a compliment of some sort (I don’t mean, “hey bro, good job,”) to counter the single offset behavior. That said, I’ve done a lot of building on Asymmetrics with asymetric layups to promote certain behaviors and to block out others.
I’ve kind of hinted at the downstroke/return stroke thing. Basically, you can break down the action of a board flexing into two operations. First, your body English is transferred into the board (board bends.) Then you unweight, and the board comes back to original shape, OS. The first transfer has a surfer in control, loading up a turn, then kind of “leaping” off the board. At this point the surfer is VULNERABLE, being unweighted, and REALLY depending upon the board to come along with them to the next position/mode of the ride. If the spot you are leaping toward MATCHES what the board does- stoked! But if the board leaps not enough or too soon, then you’ll find the mismatch to throw the timing off the remainder of a ride. (Believe me, we’ve seen this here, a couple of the board builders in our area are really into flex and you can spot a killer set-up versus a not-so-killer-set-up!) Thus, the rebound energy, how it returns to OS, is VERY important.
Hi Harry! Did you see the black a_symm last time you were here? That was my personal board, it gets borrowed SO much that I haven’t ridden it in over a year even though I nudge and ask about how my board is doing. I’ve been getting the shapes a little less asymmetric looking and focusing on asymmetric rocker and asymmetric glassing (see above.) Also been wanting to mix the foam up like I talked about, haven’t had the time, but I’d like to do a mix of EPS (rigid,) PU (semi) and PPE (bendy) in various parts of the board to enhance behavior (both in surfing and paddling.) Still messing with fins, but I think I somehow nailed the fin position out the starting gate as I’ve come full circle on it…
Good stuff, keep it coming!
Best regards,
George