Duranbah. Several waves down the coast from Duranbah (you know what I’m talking about, but it would feel weird to spell it out). Boucau, perhaps better known as the Damien Hobgood French jetty seen in Secret Machine. Twarka Bay in Nigeria. Sebastian Inlet in its prime. The Wedge in Newport Beach. What do all of these waves have in common? They are teleportation devices that can endow a surfboard with more speed than most of us should ever be trusted with. And, after a quick ’round-the-world voyage on Google Maps, we also note that all of these wedges have one thing in common: they are located next to inlet-adjacent jetties. The intended purpose of these jetties is simple: they prevent sand from filling into their respective inlets. But their unintended triangular byproducts, known to surfers as wedges, bring us much joy. Coincidence? Yeah, probably not. While most of the waves listed above have enjoyed (or possibly hated) plenty of coverage in surf media, our blue planet harbors (get it?) many other examples of inlet-adjacent chip-shots. They might not be as on-the-sand as the on-the-nose-named wave in Newport. But, when you think about it, you might even have something in your local rotation that fits this description and offers some element of a wedge, or at least a bit of swell enhancement when it counts. So, what’s going on? We decided to explore the topic with one of the greatest minds in the obscure game that is understanding why the behavior of waves through a surfing perspective — Mark Sponsler of stormsurf.com. Mark once helped us devise a formula to reverse engineer a 100-foot wave. Now, we’ll talk to him about wedges. One of the most famous photos of Slater — which has since been immortalized in a bronze statue — was generated via Wedge Power at the place Kelly was first introduced to the laws of refraction. Sebastian Inlet by Tom Dugan (as seen in 50 Years of KS) First, what is a wedge? Short answer: Two waves disguised as one. Let’s have Mark break it down. “When a wave comes in and meets some sort of structure — whether it’s below the surface like a canyon on the ocean floor or above the surface like a jetty — the wave will bend, reflect or curve in a way that it wouldn’t have done otherwise. “There are different types of refraction, and it plays a role in a lot of surf spots. Take Santa Cruz, California for example. Most of the swell comes out of the northwest, but the breaks are south-facing. The swell reacts to the bathymetry of the coast — it can take a 290-degree swell and bends it almost 90 degrees.” The two broad types of phenomena are called concave refraction and convex refraction. Concave refraction bends the bowl at you (think: Lakey Peak). Convex refraction bends spreads the wall out in front of you, often allowing for a longer wave (think: Rincon). Wave refraction is not unique to surf. In an arguably more arbitrary field — that of studying light — lenses rely on concave and convex refraction to bend lightwaves towards our pupils and shutters. “When you have a man-made structure like a jetty, you’re going to see wave refraction. The swell will reflect the energy as it interacts with the jetty. When you see a wedge, you’re seeing some of the energy that has reflected from the first wave bouncing off the structure and mingling with the second wave to create a cross-peak.” Sometimes, you don’t need a jetty. A 5000 meter/16,000 foot deep and 230 kilometer/140 mile long canyon will suffice. Nazaré, from above. Photo: Helio Antonio Does inlet + jetty = wedge? Perhaps. But not always. When it does work out, it’s likely attributed to two factors: Swell refraction, as described above. Deeper water. “Look at Nazaré, Peahi, Maverick’s — they all have deep channels outside of the focal point, which allows for a single swell to split into two swells and create a wedge. Part of the swell goes through the deep channel and, because there’s less drag on the bottom, that swell moves a lot quicker. The other half of the swell is moving slower. Just like a wave refracting off a jetty, it’s the same swell split into two. Deeper water due to an inlet could play a factor, but there are so many variables.” Still, if you’re eyeing up a coastline with brave dream of taking off behind a peak, jetties next to inlets are a good place to start. There is such a thing as too much speed. Can we reverse engineer a primitive triangular dwelling? Ok. Say you want to create a wedge. What do we do, Mark? “Ideally, I think you’d want the swell to come from some degree of the opposite direction from where you’d want the wedge to appear. For example: In Newport Beach, the wedge appears on the north side of the structure with a southwest swell. This seems to be common, but there are some exceptions. “Maybe there’s a magic formula to create a wedge with a jetty, but it would depend on a lot of factors. What’s the prevailing swell angle? What’s the prevailing swell period? What’s the bathymetry in the local area? What’s the outer bathymetry all the way out to the continental shelf? What’s the angle of the jetty relative to the prevailing swell angle? Is it a straight jetty? A curved jetty? How long is the jetty? All of that interacts to create these wedges. “People have been trying to create artificial reefs for a while now, and I’d say the success rate there has been low. My guess is that if you tried to engineer a wedge, you’d probably draw an empty well. [laughs]” The post What’s In A Wedge? appeared first on Stab Mag.
