A surfboard is an elongated platform used in the sport of surfing. They are relatively light, but strong enough to support an individual standing on them while riding a breaking wave. They were invented in Hawaii, where they were known as papa he‘e nalu in the Hawaiian language, 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. Longboards, as the name suggests, are longer (often 8 ft/2.4 m or more), and are also thicker and wider, with a more rounded nose than a shortboard, making them stable and buoyant. Shortboards are shorter (5–7 ft/1.5–2.1 m), thinner, and have a more pointed nose. They are not as wide as longboards and are typically more maneuverable. Other variants include guns, longboard guns, olos, fun-boards, fish, eggs, bonzers, quads, tow-boards, and hydrofoils.
Surfboards are usually constructed using polyurethane foam. They are made stronger with one or more small pieces of wood, called a stringer, going down the middle of the board. The foam is molded into a "blank", in the rough shape of a surfboard. Once the blanks have been made they are given to shapers. Shapers then cut, plane, and sand the board to its specifications. Finally, the board is covered in one or more layers of fiberglass cloth and resin. It is during this stage that the fins, or boxes for removable fins, are put on and the leash plug is installed. Another method of making boards is using epoxy resin and polystyrene foam, instead of polyester resin and polyurethane foam. In recent years, surfboards made out of balsa and a polystyrene core are becoming more popular. Even solid balsa surfboards are available.
Although foam boards are usually shaped by hand, the use of machines to shape them has become more popular over the years. Modern technology has made its way into surfboard production as well. Vacuum forming and modern sandwich construction techniques borrowed from other industries have become more common in the industry. Many surfers have switched to riding sandwich-construction, epoxy boards. These boards have become especially popular with beginner surfers as they provide, in most cases, a cheaper entry level surfboard as well as a more durable and resistant one.
The history of using balsa as a material for surfboard making goes back to the Hawaiians but really hits off in the late 1930s. Being light and strong, balsa wood was long considered a perfect material for surfboards. However, shapers could not use this fragile wood to make entire surfboards until after WW2 when fiberglass was invented.
The advantages of balsa wood boards is that they are a lot lighter, more buoyant and therefore easier to handle. These boards did have some disadvantages, however, because they were not as sturdy as the solid redwood. They are currently favoured by surfers and collectors because they are more durable than a regular surfboard, environmentally friendly and have a beautiful look.
A switch back to using wood after the foam revolution in the 1950's, hollow wooden surfboards are made of wood and epoxy. They specifically have no foam in their construction. (boards made with foam and wood are commonly known as compsands or veneer boards) Various construction methods are used to hollow the inside of the surfboard and lighten the weight of the completed board. Generally a hollow wood surfboard is 30% to 300% heavier than a standard foam and resin surfboard. The main inspiration apart from beauty, is to turn to a more environmentally friendly method which uses fast growing plantation wood such as Paulownia, Cedar, Spruce, Redwood, and of course Balsa.
The current methods descended from the 1930's Tom Blake paddleboarding method which favors a central stringer, with individually shaped transverse ribs, covered with a skin and lastly, rails which are then shaped. A modern interpretation of Tom Blakes work is the perimeter stringer method used by some manufacturers utilizing laminated rails as stringers, which are connected with a series of plywood ribs. This skeleton is subsequently sheathed with 5mm thick wood strips, forming a fast hollow board with better flex properties.
The parallel profile system developed by Roy Stewart is developed from cold molded (double diagonal) boat building and uses at least four layers laminated over a male mold into a curved blank, including enough wood for rails, which are then shaped. The chambering method as used by follows a system whereby planks of paulownia are selected and the rocker of the board is cut into each. The planks are then chambered to reduce weight and then bonded together to form a hollow, or "chambered" blank which is then shaped.
Many types of boards are made using any of the different construction methods, the variation of type dependent in some cases on the use for which the board is designed.
Since the late 1960s, when Gordon Clark found the optimum formulation of urethane foam, many of the surfboards in common use have been of the shortboard variety between 6 feet and 7 feet in length, with a pointed nose and a rounded or squarish tail, typically with three skegs (fins) but sometimes with two or as many as five. Surfers generally find a shortboard very quick to maneuver compared with other types of surfboards, but because of a lack of flotation due to the smaller size, harder to catch waves with, often requiring steeper, larger and more powerful waves and very late takeoffs, where the surfer catches the wave at the critical moment before it breaks.
A bonzer is a variety of surfboard created by the Campbell Brothers with three or five fins with double concave channels. The manufacturer claims that these channels create a venturi effect which guides the water off of the surface of the board through a narrowed passage.
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 innovation of a skeg in 1936 — by either or both of Woody "Spider" Brown or Tom Blake — revolutionized surfing, allowing surfers to direct the board's momentum and providing more balance whilst turning.
The template of the modern surfboard fin was developed by George Greenough in the 1960s. The single fin changed little until the late 70's, when a second was added and popularised by Australian Mark Richards. The new twin fin set up allowed much more flowing carves to be performed. Mark Richards dominated the world competitive scene from 1979 to 1983. In 1981 another Australian was developing another set up which would again change the face of surfing. His name was Simon Anderson and by attaching a third fin, positioned centrally behind the twin fins, he created the thruster set up. Today, most surfboards still use the same arrangement with its popularity arising from the combined ability for carving turns and providing control and drive.
Tunnel fins were invented in the 60's by Richard Deese, and were found on longboards by multiple manufacturers of that era, including Dewey Weber. Bob Bolen, A.K.A. 'the Greek', patented the "Turbo Tunnel" in the late 1990s. Since the mid 90's half tunnel fins have mainly been used on very long hollow wooden surfboards.
Bullet Fins were invented in the 2005 by Ron Pettibone to increase surfboard hull planing and rail-to-rail transition speed. The patent-pending fins are based on 50 years of hydrodynamic research on the bulbous bow hull design. Just as with the bow of a ship, the traditional surfboard fin creates a wave as it displaces the water in its path. The resulting turbulence places drag on the surfboard. The bulb of the Bullet Fin reduces this drag by creating a new (primary) fin wave in front of the original (secondary) wave. This new bulb wave is designed to be nearly 180 degrees out of phase with the original fin wave to subtract its turbulence thus reducing fin drag.
Winged fins are another type of surfboard fin, the genesis of which was America's Cup sailboat design. The Starfin was designed in the 1980s by the America's Cup yacht designer, Ben Lexcen, who had designed the winged keel for the America's Cup boat, Australia II. The small thruster-sized fin, the RedTip 3D is manufactured by FCS.
Fins with winglets -- tiny wings -- were invented in 2005. The purpose of winglets, as in airplane design, is to increase lift (horizontal turning force in the case of surfboard fins) while reducing drag, by reducing the fin-tip vortex.
Fins with a camber have an asymmetrical profile. In windsurfing camber is used to increase the lift to drag ratio of the fin and to minimise cavitation and the risk of spin-out. In particular windsurfers trying to improve speed records use camber fins, as the maximum performance is required on one down-wind course direction. As the camber is fixed to one side, performance when sailing in one direction is improved but performance in the other way is deteriorated.
Fins with self adjusting camber offer the improved qualities in both port side and starboard side sailing directions.