SUP Surfing Fin Shapes -How They Affect Your SUP Surfing

SUP Surfing Fin Basics

The fins on your sup board have a major impact on how your board performs on a wave. There are many different kinds of fins you can experiment with. As you become a better sup surfer you will see how different fins affect your board. You can change fins according to changing waves conditions and your riding style. Let’s take a look at basic fin characteristics and how they affect surfing performance.

How Fin Characteristics Affect SUP Surfing

Fin Base

The fin base is the width or length where the fin attaches to the board. The wider the base the more drive you will have in turns. With a wider base your turns will be more sweeping or drawn out. A shorter fin base and your turns will be a little quicker and easier but have less drive.

Fin Depth

Fin depth is measured from the bottom to the top of the fin. The deeper the fin extends into the water the more hold and stability it will give the board. A deep fin will also be harder to turn and create more drag.

Fin Area or Size

More total fin area (base and depth combined) gives a fin more hold. Larger surfers need more fin area.

Larger fins create more drag making the board slower and harder to turn. But are larger fin will also give you more hold, stability and control, especially in big surf.

A small fin will feel looser and be more forgiving but in big surf you will lose control and drive.

Fin Rake or Sweep

Fin rake is how far back a fin sweeps. The more swept back the fin the more drawn out your turns will be. (nice on bigger longer waves) A more upright fin will pivot better (nice for mushy weaker waves).

Fin Foil

Fin foil is the aerodynamic shape of a fin from front to back. Fin foil determines how the water flows around the fin like air around the wings of an airplane. The fin foil has a lot to do with grip and turns on a wave.

On the center fin the foil is the same on both sides (50/50).

Side fins often have a curved foil on the outside (rail side) and are flat on the inside. That design helps hold your board on the wave face.

Fin Toe

Fine toe is when the front of the side fins are pointed toward the center of the board. This creates more pressure on the outside foil. More pressure on the outside foil gives your board a bit more responsiveness.

Fin Cant

Fin cant is the degree of outward angle of the fin in relation to the bottom of the board. Side fins often have cant and are angled toward the rail. The center fin stands straight up and has zero cant. Side fin cant give the board more control, drive and responsiveness when turning on a wave.

Fin Flex

Fin flex or stiffness has a big impact on surfing performance. Fins are created with different combinations of flex and shape for specific types of boards and surfing styles.

Plastic fins do not have the right flex properties for surfing

A fin that has too much flex will slow down the responsiveness of your board. This is found in the cheaper plastic or “plastic-like” fins that come standard with a typical paddle board. These are inexpensive to manufacture but do not have good flex properties for surfing.

Performance riders never use plastic fins but look for a fin with an epoxy fiberglass laminate. Some high performance fins are made with carbon, kevlar and/or texalium . The core of high performance fins often have a honeycomb design for strength and lightweight.