Use physics to pull off gravity-defying surfing moves

Use physics to pull off gravity-defying surfing moves

Watching a longboarder side-step toward the front of their surfboard to hang five and then 10 toes off the nose—back arched, hands confidently locked behind them—is like admiring a magician do the unthinkable. To ride on the nose of a surfboard seemingly defies logic and physics.

But noseriding works precisely because of physics. Only a confounding force would permit a surfer to place a couple hundred pounds on the end of a plank and appear weightless, sometimes with hardly any water on the tail. Learning how the forces work will give you a leg-up in noseriding or provide you with an appreciation for the aesthetics of Newtonian law while watching the surfers from the beach.

Get comfortable withCoandӑ

While several forces might aid noseriding, the key factor that allows a rider to stand on the very tip of their board is the Coandӑ effect. This principle explains why a stream of water or air will move toward and apparently adhere to a curved surface. It’s the very phenomenon that helps create lift on an airplane wing. And it’s what seems to help a wave grip onto a board, allowing a surfer to noseride.

When a wave moves fast enough and when a board has enough surface area (on the bottom) and curvature (along its edges, or rails), a force is created. Basically, the flowing water beneath the board moves over the curved surfaces, and is redirected.

“By changing the direction of the flow, that’s introducing a force,” says Michael Burin, a physics professor at California State University, San Marcos, who studies fluids and has been surfing for 30 years. That force counters the mass of the surfer standing at the front.

While surface tension of the water, fluid mechanics, and surfboard buoyancy might factor into the equation, the Coandӑ effect is the key to noseriding. Many surfers think it’s about getting as much water as possible on the back end of the board, but it’s not really about the weight of water.

“On a crumbly day [water on the tail] might enhance noseriding,” Burin says of waves that sort of just crumble behind the main wall of water. However, he notes that when a wave is steep and hollow, a surfer hanging 10 might have hardly any water on the tail.

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You don’t need to travel to the ocean to view the Coandӑ effect; you can see it at your kitchen sink. Start by loosely holding a knife (between two fingers and from its back end) in a running stream of water. As you would expect, the stream pushes the knife away. Then do the same thing with a spoon so that water runs across the rounded backside. Unlike the knife, the spoon will be pulled up into the stream. In other words, the curve of the spoon redirects the water, creating a force which pulls the spoon, paradoxically, up toward the faucet.

Why board design matters

To take advantage of the Coandӑ effect, most noseriding boards have a convex surface on the back three quarters of the bottom deck. Many have softer rails. Both features allow water to run over this spoon-shape, directing water out to the rails and counteracting the force on the top deck.

There is, however, some debate about how the front quarter of the board should be shaped. Harry Knight, coaching director at surf coaching resort Surf Simply, told me a story about the famed surfer and board shaper Donald Takayama. As the legend goes, Takayama had been shaping a board, but slipped, taking a massive chunk out of the front quarter of his surfboard’s bottom deck. Instead of scrapping the plank, he pretended his error was a new design feature. “It turned out that it really, really helped with noseriding,” Knight said about Takayama’s first board with the accidental concave front.

Burin says a concave front could theoretically create a faster flow of water in the center, and it would also likely create more side-to-side stability.

In the 1990s, Bob Howard invented a spoon-like device called the Koanda Noserider, which was the shape of a baseball helmet and got positioned over the fin, enhancing the Coandӑ effect. Israel Paskowitz used the contraption in a contest and rode on the nose of his board for a ridiculous 16.5 seconds, a lifetime in noseriding.

The location of a board’s widest point could also affect noseriding, at least according to the narrator of Surfing Explained, the 12th episode of Surf Simply’s YouTube video. For instance, having the widest point of the board near the rear would be best for proficient surfers who want to noseride on steep, fast waves, whereas a board that’s widest at the front would be the best choice for beginning surfers wanting to put their toes on the nose, or for surfers noseriding softer waves. In the end, getting the wave to curl around the rails and grip the board as much as possible increases the force from Coandӑ.

Think of the wave as a mouth and the board a sandwich. But this is a mouth hungry for the crust. The more crust you give it, the better bite it has on the sandwich, allowing you—let’s say the pickle—to stand with your back arched, covered with goosebumps, the way any good pickle should be.

How to find the right wave

Down in Costa Rica, Knight, a self-proclaimed surf nerd, applies science to his Surf Simply lessons just as he does with the science-heavy podcast and YouTube channel he and his co-founder produce.

“Most people want to [noseride] when the wave gets calmer, but then you have less lift and less weight on the tail and wrapping on the rails,” Knight says.

The first step for an already-competent longboarder to reach the nose is to be able to identify sections of the wave that are steep and fast. Next is to perfect the stall or turn that places you in the wave’s sweet spot—just in front of the breaking section. Once there, walk forward, but not with the intention of getting to the nose—just to pass the balance point, which is typically at the middle—and then step back, Knight says. Repeat this until you get a feel for the board in trim and understand when it is counterbalanced by the wave (and when it’s not). Eventually, your goal is to cross-step to the nose. The cross-step is important, too, Knight explains, as it allows you to move your weight more fluidly.

In a noseriding.com interview, Steve Walden, famed shaper and surfer, suggests trimming at the top half of a wave before moving up to the nose.

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A long point break, where a nice wall builds up and runs long, is the best spot to try noseriding. It affords you time to generate speed and allows the Coandӑ effect to take hold before you run out of room to noseride. Beach breaks tend to be an inferior option because the ride ends too quickly.

The next time you’re out in the water, know that the art of noseriding is created with the careful strokes of Newtonian physics. And applying these ideas and laws correctly can transform a kook into a Jedi Boardwalker who reaches the tip. May the Coandӑ effect be with you.

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