In part two of our examination of Surfboard fins, we examine why surfboards are approached as if they are living things and yet fins, the very things that make surfboards possible to ride, are often just afterthoughts. When in fact it takes the same commitment to design, the same passion of thought and even greater cosmic science to create a surfboard fin. Might surfboard fins be infused with the same mythical, soulful elements of surfboards themselves? Can surfers have the same relationship with a set of “magic” fins” as they do with “magic” Surfboards? The following is our second conversation with Vince Longo, the Chief Design Officer of Future fins and, when it comes to surfboard fins, one of the most knowledgeable humans on earth. The conversation was like a round table talk at NASA. So, in the interest of science and soul, here are the pertinent points of Vince Longo:
-Of course fins can give you a soulful feeling. They are half the equation of a magic board. How many of us get a new board and put it under our arm and look in the reflection of a window to see how beautiful it is. Try that with fins sometime.
– Fins create a pressure difference. And with that difference they allow you to change direction. Fins break up the water flow so that they make the flow unstable and allow you to change direction more easily. On one side of the fin is high pressure and on the other side low pressure. Just like an airplane wing. This causes instability. Because of that instability you can actually direct where you want to go. That’s it. But it’s still rocket science.
-Actual fish in the ocean, their fins can be controlled and contoured by their muscles. Surfboards do not have that luxury, so we must make due with a rigid, inanimate object. But the directional dynamics remains the same.
-Gravity has everything to do with generating speed when it comes to surfboard fins. You use gravity to drop down a wave, but it is the fins that actually allow you to create the pressure to get back up the face of the wave. Without the bottom turn, top of the wave maneuvers would not exist.
– A spin out is caused when you lose the laminar flow of water against the fin. The water is actually holding your fin in its grip. But when the turbulence, or disruption you are causing becomes too great, the water will let go of its grip and you will spin out.
– You surf a thruster, you guide a vertically placed twin fin fish design.
– Interesting that fluid surfing is made possible by instability.
– The single fin surfboard is far more dependent on rail work. Because with the double foil of a single fin, you must lean the board into the wave in order to create the fin angle yourself, so that you can create that pressure difference. There is no cant or tow in. It’s up to you. Foil allows the water to grab the fin in front and create the turbulence in the back. Allowing the turn you want.
– With thrusters you have fins working together. So as soon as you have that turn, you have two side fins lifting and creating instability and pressure together. So the side fins are working with the rail and the center fin is the foil stabilizing it all. So the real key to understanding the Thruster fin set-up is understanding that the side fins and the rails are working so close together.
– Finless surfboards? Sure, it is possible to use just the rails to go places. But watch those guys. It takes an incredibly low center of gravity to make it happen. You are almost permanently in a low, careful crouch. Great feeling though.
– Thruster fin placement all over the world is almost identical.
– With twin fins, without your center fin the rudder dynamic, your point of turn becomes more of a pivot.
– The back fin of a Thruster is double foiled so that it can handle the necessary pressure dynamics in both directions. Simple.
– With tube riding, the thruster allows a far more sensitive ability to climb and drop inside the tube. That is why they seem superior for deep tube riding to single fins. The single fin needs a perfect tube and a perfect line to work optimally.
– The language we use with the CT guys is about stiffness, looseness and area. That is their main concern. I think for John John, him dialing in his area of the fin is his key.
– We do not get our most precise feedback from John John and Jordy and all the CT guys we have on our team. The CT guys just want things that work. Fair enough.
-The best test pilots are the guys that have been on the CT but then have retired. They have more time to experiment and feel things out. No longer concerned with being fashionable to the judges.
-Jordy comes strongly to mind when we talk about fin size and area. Completed maneuvers are about fins with the right area for the surfer. Too much area and it’s tracky, too little and you have no follow through. Jordy is highly tuned into this.
– You can break a fin down into two elements. Area in the tip and area at the base. For the actual heavy duty contours of the fin we depend on physics and computers and close observation to get the greatest flow quotients. This is what makes those shaper dots on the bottom of your board so significant. Shapers place fins alot on feel. That’s why feedback from the surfer to the shaper about fin placement is so critical to the board’s performance.
-Shaper’s know alot more about fins than their riders do.
-Some surfers, like Jack Freestone, pay attention to foil for different conditions. For example, he rides more foil in small junky surf an flatter foils for Teahupoo. So that he can control his speeds easier.
-I hear from our riders that the key to surfing Teahupoo is controlling your speed. A real fine line there to stay in the tube. The wave wants to spit you out. And with no face, its hard to stall. Freestone believes the right fin foil can make the difference between winning and losing when it gets that heavy. Speed control.
– When people ask me which fins to use I say, Machado has fin tip flex and fatter foil for fluidity and Jordy has more area and flatter, stiffer profiles for more brute force. Where do you fit in?
– We also break down fins for specific spots. Trestles as opposed to Pipe and so forth. When you wanna generate speed you want more foil and flex. To control your speed, flat foil and stiff. That is the basic spectrum of design.
-Once you lay into a turn the place behind the shaper’s dot becomes real important.
The trailing edge of the base. Everything we make is based on those shaper’s dots.
– Computational fluid dynamics. That’s us. We are currently working with the guy that does all the car foils for Lamborghini and the Formula 1 guys. The future of surfboard fins has never been brighter than right now.
After all… Fins are all about the turning in the right direction, right?