A surfboard is an elongated platform used in the sport of surfing. Surfboards are relatively light, but are strong enough to support an individual standing on them while riding a Ocean surface wave breaking wave. They were invented in ancient Hawaii, where they were known as papa he’e nalu in the Hawaiian language, they were usually made of wood from local trees, such as koa, and were often over 15 feet (5 m) in length and extremely heavy. Major advances over the years include the addition of one or more fins on the bottom rear of the board to improve directional stability, and numerous improvements in materials and shape.
Modern surfboards are made of polyurethane or polystyrene foam covered with layers of fiberglass cloth, and polyester or epoxy resin. The result is a light and strong surfboard that is buoyant and maneuverable. Recent developments in surfboard technology have included the use of carbon fiber and kevlar composites. Each year, approximately 400,000 surfboards are manufactured.
Modern surfboards often contain multiple contours on the bottom of the board, termed concaves. These concaves have different uses and vary among different types of surfboards. Most concaves on the modern shortboard begin about twelve inches (300 mm) back from the nose of the board on the bottom and then carry out through the middle to the tail of the surfboard. The purpose of concave is to direct water through the fins of the surfboard. Surfboard shapers sometimes experiment with concaves to create different drive and response characteristics on each individual surfboard.
Some older and more traditional surfboards along with many modern boards that take inspiration from these older boards utilize a convex rather than concave design on the bottom of the surfboard. These boards displace more water and sit lower in the wave than a surfboard with a concave bottom
The deck is the surface of the board that the surfer stands on. Surfwax is applied to this surface. Wax comes in different degrees of hardness allowing its application in differing water temperatures.
The surfboard fin is a stabilizing rudder fixed to the rear of the surfboard to prevent it from sliding sideways. In the early days, surfers would stabilize the board by hanging the toes of their back foot over the edge of the board and would steer by putting their foot in the water. The American surfer Tom Blake was the first to experiment with adding a fin to a surfboard, fastening the keel from an old speedboat to a surfboard in 1935. About one or two years later, Woody “Spider” Brown independently developed a similar design, but Brown himself gave Blake precedence: “(I made my first surfboard keel) about ’36 or ’37, somewhere in there; about the same time. But, I didn’t know anything about (Blake) and his experiments with adding fins to surfboards. See, we were all separated out. I was in San Diego and he was in L.A., way up there.”. This innovation revolutionized surfing, allowing surfers to direct the board’s momentum and providing more balance when turning.