Fins: the patent filed by Tom Morey and Karl Pope in 1961

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 been playing a very important role in the development of high-performance surfing. Surfboards shapes and fins are talking to each other, more than ever.

We've learned that there are nine major characteristics in a surf fin: material, base, depth, sweep, area, cant, toe, foil and flexibility. Alongside with your weight, these variables will influence the drive, pivot and hold behavior of a fin setup.

FCS has published a surfer's weight table which resolves a classic fin dilemma. What's the best fin size for your weight?

Fin Size Surfer's Weight
XS Under 55kg
S 55-70kg
M 65-80kg
L 75-90kg
XL Over 85kg


Having chosen the best fin size for your weight, it's time to take a look at seven fin characteristics: Base, Depth/Height, Area, Sweep, Foil, Flex and Cant.

Fin Base: influencing drive

BASE

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, in bottom turns.

Fin Depth: influencing hold

DEPTH/HEIGHT

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 fit them better.

Fin Area: influencing hold

AREA

Area is the total surface area of the fin. The more area, the more hold the fin will have.

Fin Sweep: influencing pivot

SWEEP

Sweep, also known as rake, is the angle measuring how far the outline of the fin is curved backwards. Sweep has a direct influence on pivot. Fins with more sweep produce a longer turning arc, while less sweep offers a tighter turning arc.

Fin Flex: influencing responsiveness

FLEX

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 instant response, speed and drive. Flexible fins are more forgiving and offer a whipping sensation.

Fin Cant: influencing stiffness

CANT

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 gives the board a loose feel.

Fin Foil: influencing flow

FOIL

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.
  
FLAT FOIL: 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.

INSIDE FOIL: A sophisticated hydrodynamic foil consisting of a convex outside face, a rounded leading edge and a concaved 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 with more options through increased hold and speed.

50/50 FOIL: A symmetrical foil used on all centre 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 centre 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)

Thruster Foil Setups

Quad Foil Setups

FCS and Future Fins are the most popular surfboard fins in the world, but there are more options.
Discover the complete range of brands working with surf fins.
Get the best fin setup for a particular wave type.