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Displacement Hull Theory



The Displacement Hull surfboards design is a part of surfboard's history. This design came with the shortboard revolution in the 70's. Mostly from Nat Young and his Keyo single fin, Wayne Lynch making shorter boards and Yater who were experimenting S-deck rocker narrower tail outlines and thinner flex fin for Rincon, California. Georges Greenough and his spoon design and flex fins were also bringing something magical which pushed everything in the shortboard revolution and displacement hulls. From that era many shapers started making boards with those kinds of designs.  Greg Liddle pushed the designs and experimentation pretty far, which gave the designs a bit more famous and multi purpose. The hulls designs fit inside a curl and attract water around their rolled nose, they are immersing into a communion of time and speed. To do not disturb the flow. This generous design is made for being one with the fluid dynamic of the wave and to minimize the break of the flow. The displacement hull is inspired from boat design, the hull ( the belly vee on the nose of the board) is displacing/pushing water for clean and prepare the surface to the flat bottom shape for perfect glide, and so more speed. When it's not a flat bottom shape but a tri plane displacement hull (three different planning surfaces) this combination push water and once the water will pass from the tail it will create an elevation, and this is the typical feeling of a planning hull. Flying on the water. The rails are 50/50 or mostly inverse (60 bottom 40% top) for being more stuck in the hollow of the wave. And the surface of the board which will be stuck into the wave will be only the rails due to the belly inverse rail, so the bottom will be more planning, will be less in contact with water, because the goal is to have less friction as possible with water, to get more speed as possible then. But the good thing with hull is once that rail will be stuck into the hollow, the wave will move the board with the wave itself, you'll never go faster than the wave, it's for that Hulls are also a board which need to be ridden in hollow and fast wave.The Rocker is very low, specially tail rocker, which is not easy to ride, but it's one of the best tool to get easy speed. The bottom shape is flat from the tail until the widest point and then turn to a big belly vee, the famous "hull". Then one other particularity of the displacement hull is the S-Deck. Wich mean if you look at the rocker of the board, you can see on the top this weird design which look like a S. This gonna lighten the board, because you'll surf only on one point: the widest point which is far forward on the board, with your two feet close, so you don't need volume somewhere else, you need only volume under your feet, and the S-deck will make the perfect balance. Due to the position of the feet far forward, the fin is far forward too, so you'll have the control/drive of the board while staying on the front of the board. The fin is flex, mostly made with volan fiberglass ( because volan is more flex than small number fiberglass 4oz, 6oz...) The fin as a really serious role. Because with this kind of design you will make your bottom turn in two times. First time you'll take off and go straight, and then you'll start making a big turn and push on your back foot, then the flex fin will react and project/propulse you into the pocket of the wave where all the wave's energy is. And this feeling is amazing and proper to Displacement Hulls designs. The Displacement Hull is not an easy board to ride. It's not an "egg" or easy single fin to ride. It's really hard to understand the goal and the way to ride it. Specially the bottom turn. Once the board is stuck into the wave, you'll have nothing to do, the board will do the job by itself and the less you do the more speed you get. But If you never surfed hulls before, you'll need a few waves or session to understand it. But for me it's the best feeling ever, and it's the best design about single fin. The feeling is hard to describe, but it's make you surfing with style, and glide with 100% of the wave's energy. You can feel the "smooth" feeling which is amazing. But you can also feel as the board is like a knife is the water, cutting long curves, long cut back.Those boards doesn't work on flat waves. You'll need a fast and hollow wave. The best is to surf it on point break but you can surf it on beach break too, just need a clean hollow wave.Of course this board is made for a fast but smooth glide, you'll surf it with less turn as possible, you are looking to feel the dynamics of the wave...that's all.