The person makes the board faster. If not for the person the board would only go as fast as the wave is going as it crumbles towards shore.
For most surfers its about harnessing the speed and finding the best set of variables in the board for the rider and the conditions being ridden. The board that works great in mushburgers often doesn’t work in powerful surf and vise-versa.
Rocker by far is the biggest speed factor. Why tail rocker? On the take-off it gives the wave something to push against rather than flow around. When riding there is less turbulence/ flow /
disruption. After that the smoother the skin the faster.
To go straight forward, the fastest is probably the flatest and the one with enough volume to support the surfer weight but not too much more.
But, as Mako said, the goal in surfing is not to go fast directly yo the beach but to use the wave at it max potential (up-down-forward-backward) so the alchemy is much more complexe.
The more tail rocker (and nose rocker) you put on the board, the more “generally concave” it becomes. So if you stand on surf position, the more rocker you have the more board you tend to sink under water.
So you push more water than a flatter board.
An more developed lecture is available on Greenlight website:
I agree with Mako - Obviously the rider does play a factor in the speed of the board, but the rider does so by manipulating the control surfaces of the board. Yeah a board with nobody on it will only go as fast as the wave as it crumbles towards shore - but that’s assuming the board is going in a straight line. If the board is pushed down the line as a surfer would it will then generate more speed depending on which part of the wave the board is in at a given time.
So I’d say you’re right in that 75% of the speed comes from the rider keeping the board in the optimal point of the wave - but there are different shapes that will fit better into different pockets to take advantage of the particular style of wave (hence why longboarders on the shoulder can be faster than shortboarders in the pocket).
That said, I will say there are two major factors in the surfboard that promote speed - planing surface and rail angle. Wider boards, longer boards, or boards that have low rocker all have more surface area contacting the water, which translates to more speed. Straighter rails also mean more speed (but also less maneuverability) - which is why Tomo boards, mini simmons, noseriders and alaia’s fly down waves that barely even have any push to them.
shushka420,
Why more surface area=more speed?
More surface touching water=more friction=more drag(less speed)
What you mean by saying straighter rails? Like more boxy ones?
Mostly what Brian said as far as the balancing act, but I see where it’s confusing. It seems like more surface area touching the water is more drag but it really isn’t. The surfboard is a planing hull and it relies on its planning surface to function properly. I’m not sure about the science and math behind it, but I do know that when you increase planning area you get a faster board - that’s a huge part of why guns and soft tops paddle so fast. One would think that’s due to the buoyancy, but if you ever get the chance to experiment you’ll notice that paddling a short, narrow but thick and corky board is never as fast as a longer or wider board with less thickness.
As for “straighter rails” in referring to the angle of attack from nose to tail. The more curve your board has the better and more responsively it turns, but the more drag you create because of turbulence, while longer, straighter rails with less curve (like a long board) shed less speed since less of the rail is moving against the water, but they also sacrifice maneuverability
They’re thinking of wetted area when they talk about surface area, right? More wetted area might induce more drag.
I don’t know the math, but I would imagine drag as a function of surface area doesn’t go up as fast as speed as a function of surface area. So an increase in SA might increase speed more than it increases drag due to more wetted area. No idea if that’s right, but it seems logical. I have a 5’4"x20.5 with a 17" tail and 15.5" nose. It’s blocky and wide and it flies. Surface area doesn’t seem to hurt it.
Yeah I think that’s the key - the increase in drag is minimal compared to the increase in speed - and yeah I definitely mean the wetted area. The science seems sound though - A big factor is the shape of the wetted area too - concaves give a smoother release and convex creates more drag - that’s why boards with a lot of belly aren’t as fast as boards with more concave… water sticks to convex surfaces and releases from concaves/hard angles
I was under the impression that it wasn’t the concave on a longboard that slowed it down while noseriding, but it was the transition to flat that did. The transistions point caused a push. A deep teardrop concave has a steep transition point and therefore has more effect on slowing a board downt then a blended more shallow concave. A concave by itself is a faster bottom due to its effect on rocker.
I think speed is dependent on the kind of wave you’re riding. In some waves a flat bottom will be faster, in others a concave bottom. I’ve never ridden a true hull board, so I can’t say what they work best in, but I’d bet they aren’t the fastest in all waves.
Personally, I like flat bottoms more than any other, but I’m not riding really fast hollow waves. I tend to surf deeper water with slightly slopier faces, more almond eye curls and not round, super shallow reef waves. I think concaves help in powerful waves, but I’m not sure they are faster. I think you get better control.
Board length and rocker will also add to overall speed. Less rocker tends to be faster, but on a longer board the rocker is stretched over more distance, so it’s not as curvy as the same amount of rocker on a shorter board. You can also pump short boards with better results than you can on longboards, so there’s other ways of getting speed.
Some of the fastest boards I saw back in the early 70’s were the original fish boards. Short, wide, flatter rocker made them fast.
Finally the rail shape will help make a board faster or slower. Add an edge to the bottom of a rail and it will make the board faster.
If you’re referring to the spoon/dish in the front of the board then, no - it creates lift under the nose.
If you’re doubting that water sticks to a convex and releases from a concave, that’s an irrefutable law of hydrodynamics thanks to surface tension.
Otherwise, like I said I’m not sure about the science behind it, but I did account for the fact that different shapes are better suited for different wave styles.
Maybe I’m just missng the point you’re trying to make?
The fact that it is a hull isn’t what makes it fast - hulls plow water they don’t plane it. The hull boards get their speed from their length and overall shape, and if you don’t know how to properly ride one they’re a dog in the water. And I can gurantee you a hulled shortboard would in no way be faster than a concave shortboard. That all seems accountable in my statement.