Rake, Foil, Cant, Flex, Fin

In an attempt to keep everyone happy with what I’m about to say, please consider the following; surfboard design is not an absolute.  Just like their are hammers designs for different of jobs, there are surfboards for different purposes.  Hammers are much more exact because they are only adjusting to the size and weight of a nail.  Surfboards have to account for size and weight of their operators while also considering wave shape, size, and power.  Of course, there is the whole issue of skill and wave knowledge but that is another blog.

I feel like starting an argument today so let’s talk about fins!  I’m not going to talk about what I like or which way is best because that depends on a countless number of factors and my mood.  For learning purposes, let’s go over a couple terms and ideas that I find most people are unaware of and are crucial to how you approach surfing on your board.  While most of these individual characteristics are pretty well agreed upon within in the shaping community, how they work in relation to each other is up to professional debate.

Toe

Toes is essential the angle of your fins in relation to the stringer or imaginary centerline, if your board is sans-stringer.  This can have a dramatic effect on how much drive your board has and how loose is feels under speed.  When the fins are turned towards the stringer(the red line), pressure builds on the outside walls of the fins.  This pressure makes the board feel “loose” allowing the front edge of the fin to use the pressure towards pivoting the front half of the board.

A simple diagram explaining what ‘toe’ is referring to with surfboard fins.

Cant

Cant is basically how the fin leans towards the bottom surface of the board.  This can have a couple different effects on how a board behaves.  The can’t can react with the outline of the board on how much hold it has in the face of a wave but can also help the board be more reactive through turns.  When a fin is sticking straight up and down, it is said to have no cant.  Cant only leans towards the rails.  To my knowledge, I have yet to see a board that has fins canting towards the stringer.  Cant is achieved through both fin box placement and fin templates.  A good example of a fin template with a lot of cant would be the old FCS TC Aqualines.  I still get nostalgic fuzzies on my insides when I remember how the reacted through cutbacks.  While a heavily canted fin can lead to less drive, on some days, less drive helps you stay in the sweetest part of wave.

Foil

Foil refers the the hydrodynamic design that most modern fins have taken on.  If you take a close look at your fins, you’ll notice that they are not flat.  One side might bulge out at the center while remaining thin on the edges.  This is usually combined with some sort of scoop from the center of the other side.  Center fins, if your configuration has a true center fin, is usually bulged on both sides.  The goal of foil is to create lift for the back end of your board.

Flex

Flex is exactly what it sounds like; it refers to the ability of a a fin to bend.  Flex allows you to make sharp turns and recover with the recoil of the fin to shape.  A stiffer fin is better for a beginner who might need stability, however, they may struggle as the begin to learn maneuvers.

Rake

Rake is essentially how far back the tip of the fin reaches beyond the base.  While a large rake can be great for helping maintain drive through turns and creating stability, it also creates a wider turn.  For a sharper turning radius, consider less rake.  Rake becomes very important when considering turning longboards and nose riding.

These might seem complicated at first, but they are truly just the tip of an ever-evolving iceberg.  You truly need to experiment and consider these factors of various board shapes and wave conditions.  Also, be sure to check yo self.  Most things you see in today’s fin market work.  You may not be surfing them correctly.  Don’t get mad at the hammer for not being able to cut a 2×4!  There will certainly be more on this topic in the future.

FIN!