Fins are getting more attention from surfers because they can provide the drive, pivot, and hold characteristics needed in standard or special surfing conditions. Learn everything you need to know about fins.
Science and hydrodynamics have played a very important role in the development of high-performance surfing.
Surfboard shapes and fin designs are talking to each other now more than ever.
We've learned that a surf fin has nine major characteristics: material, base, depth, sweep, area, cant, toe, foil, and flexibility.
Along with your weight, these variables will influence the drive, pivot, and hold behaviors of a fin setup.
FCS has published a surfer's weight table that resolves a classic fin dilemma: what is the best fin size for your weight?
Fin Size > Surfer's Weight
XS: Under 55 kgs (121 lbs)
S: 55-70 kgs (121-154 lbs)
M: 65-80 kgs (143-176 lbs)
L: 75-90 kgs (165-198 lbs)
XL: Over 85 kgs (187 lbs)
Having chosen the best fin size for your weight, it's time to look at seven fin characteristics: Base, Depth/Height, Area, Sweep, Foil, Flex, and Cant.
Base is the length between the leading and trailing edge where the fin meets the board. Base is primarily linked to drive. Fins with a longer base will have more drive and acceleration, for example, on bottom turns.
Depth/Height is the distance the fin penetrates into the water, and it directly relates to hold. The greater the depth, the more hold; the shorter the depth, the more a board will slide and release. Taller surfers might find that deeper fins suit them better.
Area is the total surface area of the fin. The more area, the more hold the fin will have.
Sweep, also known as rake, is the angle measuring how far the outline of the fin is curved backward. Sweep has a direct influence on pivot. Fins with more sweep produce a longer turning arc, while less sweep offers a tighter turning arc.
Flex refers to the distortion of the fin from its original shape caused by lateral pressure during a maneuver.
Flex influences the response characteristics of a fin. Stiff fins produce an instant response, speed, and drive. Flexible fins are more forgiving and give a whipping sensation.
Cant refers to the angle of the side fins measured from a vertical line perpendicular to the flat bottom surface of the board.
Cant has a direct effect on acceleration and maneuverability. Less cant produces faster acceleration and a stiffer feel. More cant will increase maneuverability and give the board a loose feel.
Foil refers to the shape and geometry of the inside and outside faces of the fin. Foils directly affect the flow of water over the surface of the fin.
A flat inside face combined with a convex outside face. The traditional flat-sided foil offers an even combination of drive, pivot, and hold and provides a very consistent, reliable feel over a wide variety of conditions.
A sophisticated hydrodynamic foil consisting of a convex outside face, a rounded leading edge, and a concave inside face. Inside foil increases the efficiency of water flow over the surface of the fin, adding lift and reducing drag. The result is a fin that gives the rider more options through increased hold and speed.
A symmetrical foil used on all center fins where both sides are convex. Even water flow on both sides creates stability and control.
70/30 or 80/20 Foil
Combines the performance of a center and side fin, offering increased speed, smooth rail-to-rail transitions, and a consistent feel in a variety of conditions. (Ideal for all board types and rear fin placements)
FCS and Future Fins are the most popular surfboard fins in the world, but there are more options.