Surfboard

A surfboard is a narrow plank used in surfing. Surfboards are relatively light, but are strong enough to support an individual standing on them while riding an ocean wave. They were invented in ancient Hawaii (known as papa heʻe nalu in Hawaiian) and were usually made of wood from local trees, such as koa. They were often over 460 cm (15 ft) in length and extremely heavy. Major advances over the years include the addition of one or more fins (skegs) 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. Unlike soft top surfboards, hard top surfboards are also covered with layers of fiberglass cloth, 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, as well as experimentation in biodegradable and ecologically friendly resins made from organic sources. Each year, approximately 400,000 surfboards are manufactured.

Choice of surf board type and size can be complex. Depending, amongst other things, on:

Traditionally board lengths have been sized according to the height of the surfer, meaning in general that longer boards would be recommended for taller surfers. Standard dimensions for board size has for long been the board's length, width and thickness. More recently however, the weight of the surfer has also started to be taken into account, meaning in general that a heavier surfer would be recommended a board with more volume.

The surface of the board that rests on the water is usually flat or concave but sometimes convex. The bottom can also feature channels, chines, steps and other planing features shaped into the board in order to maximize, direct or alter water flow across the board's bottom surface.

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 30 cm (12 in) 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. Contours such as concaves (similar to the deck of a skateboard) or rail channels (to add structural rigidity) can also be shaped into the deck. Surfwax is applied to this surface. Wax comes in different degrees of hardness allowing its application in differing water temperatures. The ideal choice of wax hardness is determined by the water temperature.