How Fin Design Affects Board Performance

Posted by Bryan Gordon on

diagram of surf board fins flex, foil, and rake

Many details go into making a wakesurf board perform. Believe it or not, fins are one of the most important of those details. Below we tap into some reasons fins play such a big role in how your wakesurf board rides. 

A template basically consists of 3 parts:

  1. the base
  2. the height 
  3. the rake.

The BASE of the fin, which is the closest part of the fin to the board, essentially determines how much drive you will have. When coming out of a turn, a bigger base will give you more drive, which is also relative to a person's weight. Think about it like an Indy car tire vs a standard car tire. When accelerating out of a turn with a wide Indy car tire you can get more drive, or accelerate more out of a turn, with the added surface area as opposed to skidding around the turn with a standard car tire. A WIDER BASE WILL HELP IF YOU NEED MORE DRIVE OUT OF TURNS. 

The HEIGHT of the fin will be determined by how big a person is. A fins height is like a T-Shirt. The bigger the person, the more surface area they will need. A little bit more fin height will help a bigger person with stability. 

Next is RAKE. Rake is how much the fin actually sweeps backward. The more rake, the more round your turns will be. The less rake or more vertical a fin is, the more you will be able to pivot your board quickly.


The FOIL is essentially the same as an airplane wing.
As the water flows on the outside of the fin, it creates low pressure, and the water on the inside of the fin (closest to the center of the board) creates high pressure. The water on the inside of the fin pushes against the fin to the area of low pressure which is on the outside of the fin. That's what helps you to stay close to the wave face, and also what helps a plane stay in the air. MAKE SENSE!?
Also, the amount that the inside of your fin is "cupped" is a big factor as well.
You will notice some fins are flat on the inside and some are concave or cupped.
The flatter inside foil will help you control speed but not really help on generating speed as much as a foiled fin.
In a nutshell, you don't need as much foil with a bigger wave because it already creates speed for you, but with a smaller a wave, the increased foil will help generate more speed, and it will help you from rail to rail.


Outside of the template, the FLEX of the fin plays a large role. Flex is the movement of the fin laterally. On bigger waves, you need more hold to stay in the face of the wave so you don't need much flex, as flex would cause less hold in that situation. You need more flex in smaller waves so that when you turn, the fins will flex then snap back to their natural position, giving you a "spring" like effect and more power out of the turn; helping you to get back into the wave faster.


When choosing your next wakesurf board, make sure the manufacturer offers removable fins that you can upgrade to a higher performance fin when you're ready to take it to the next level. Doomswell Wakesurf boards come standard with Futures Fin system and can be customized to other removable systems such as FCS, Fin-s, Etc.


Along with your fins, the grip is another detail affecting performance. If you can't grip, you can't ride. Check out "Wax vs Traction" to learn more. 

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