Surfing
In surfing, windsurfing, and kitesurfing the fin, sometimes known as a skeg, is located towards the rear of the surfboard. A surf board fin improves the board's directional stability and enables directional control by banking, known as foot-steering, which involves varying the surfer's side to side weight distribution.
The fin was introduced in 1936 by Woody "Spider" Brown", later inventor of the modern catamaran, when he built America's first modern surfboard (i.e., capable of being surfed standing up) using principles learned during his decade of aeronautical experience. Despite this, it is usually attributed to Tom Blake. Blake claimed to have removed a skeg from a water ski then screwed it onto the bottom of his solid wood board (not capable of being surfed standing up). Brown, whose later invention of the catamaran was subsequently patented by Hobie Alter, similarly refused to contest this claim.
Small single aluminum fins first evolved into single larger wooden, then fiberglass and carbon versions. In early surf boards the beaks from Duck-Foxes were used. In time hydrodynamic improvements took place, pioneered by George Downey who also created the first removable skeg, a teak wood skeg in a teak wood box which was supposed to hold in place due to the swelling of woods in water. In modern surfing board design, the conventional set up is 3 fins, with single fins being a minority. Most windsurfing boards are single fin. However, wave boards now feature some twin fin, tri fin and quad fin designs. Directional kitesurfing boards are usually 3 fin, with 5 fin designs being used for improved upwind performance.
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