- Fin Shape - This is the shape of an individual fin in the set. This is broken down into three main areas:
Base length and depth (height from base): These are your basic dimensions. Base length is the widest point of the fin and it occurs at the base of the fin where it attaches to the surfboard. A longer base allows for more speed generation as more water is trapped in the surface area of the fin. A shorter base will allow for a sharper turning radius. Depth will impact the amount of hold you feel. The deeper the fin, the more hold through turns. Shallower fins will release and slide more during turns.
Rake/Sweep: This is how far the front edge of a fin arcs backwards to the tip of the fin. Fins with a small rake help propel the board, are very stable and predictable but are not ideal for making sharp fast turns. On the other hand, fins with a large rake angle will allow your board to have a tighter turning radius, but will make the board feel more loose and prone to slide.
- Foil, Flex and Cant: Foil refers to the shape of the outside and inside faces of your fin, and affects how the fins grip the water, Flex will be determined by the construction of the fin. More flexible material will allow for the tip to slide, reducing the fin’s hold in the water. A stiffer construction will offer more predictability and hold. Cant is the degree tilt of the fin from the base to the tip. A more canted fin will offer a more loose feel, where a less canted fin will be more stable.
Fin Setup - This refers to the placement and number of fins that you run on your surfboard. There is a lot out there, so I have narrowed it down to the 6 main set-ups.
*IMPORTANT: Check that your surfboard’s fin boxes are compatible with the fin set (for example, an FCS brand fin set will not fit in a surfboard with Futures brand fin boxes/ inserts).*
- Single - This is an old school classic. Originating from Tom Blake’s initial creation, and later made famous by the likes of Gerry Lopez, who pushed radical turns and tube riding with single fin surfboards. Use a single fin on retro shortboards, mid-lengths, and longboards for a loose, flowy, retro feel.
“2 + 1” - This is a single fin box, with added ‘side-bites’ on either flank for added stability. Use this if you are looking for more hold and stability out of your single fin and for a wider arc in your turn.
Twin - For a while this was considered the pinnacle of ‘performance’ surfing due to the speed generation it allowed for, as well as the ability to ‘disengage’ and perform radical maneuvers such as airs and fin release turns. See Mark Richards for some early and smooth twin-fin surfing. Note that while the twin fin is no longer at the core of competitive surfing, twin fins have exploded in a realm of their own, with the likes of Mikey February drawing innovative and timeless lines.
Thruster - The thruster was the next step in the evolution of performance surfing after the twin fin. The addition of the center fin, as well as the reduction in size of the side or ‘trailer’ fins allowed for radical pivot and carve maneuvers, whilst still allowing for looseness and release where and when the skilled surfer wanted it. The thruster dominated in the 80s till the 2000s as the most dependable and versatile set up. See Tom Curren at Jbay set the standard here for how one should ride a thruster set up on a shortboard.
- Quad - Think of the Quad fin set up as an iteration of the twin fin set up, with an added smaller set of inner 2 fins called quad rear fins. These smaller fins trap more water, adding more hold and resistance than a traditional twin fin, whilst still allowing uninterrupted water flow through the center of the board. Thus with a quad fin you can achieve the same flowy, fast feeling of a twin fin, with a bit more hold and stability. One of my all time favorite surf movie segments shows Dave Rastovich and his appealing argument for the quad fin.