Surfboard fins are possibly the most underrated element of a surfboard. Choosing the right fins for your style of surfing and your board is critical in making sure you get the best level of performance from your surfing.
What Are Surfboard Fins?
Broadly speaking there are three key facets to the surfboard fin. The first one is pretty straightforward, and that is whether the fins attachable or integrated. Most modern surfboards are shaped with fin boxes, which allows for the fins to be clipped in.
The upside to this is that you can customise your surfboard based on different surfing conditions. More on that later. The second advantage is that it makes transporting your surfboard much easier, as without the fins it can easily be slipped into a surfboard travel bag.
A lot of retro boards like Malibu’s from the 60’s and 70’s and two-fin fish boards have integrated fins. This is for the simple fact that when these boards where being made in yesteryears, clip-in fins were not available.
The two most important elements of surfboard fins are the size and shape of the fins and how you setup your fins on a modern surfboard. However, there are a plethora of other variables to consider with surfboard fins as you’ll see below.
The size of the fin will dictate your performance on a surfboard. A larger fin generally will provide more hold and also give you plenty of control in bigger surf.
A smaller fin is going to be more loose and forgiving, but you’re going to sacrifice a lot of control and drive in bigger swell.
This is the part of the fin that is attached to the board. A longer fin base is going to improve your drive down the line. This translates into more drawn out turns. A short fin base on the other hand is going to let you turn the board on a dime, but with less drive get from a wide, arcing turn.
Fin rake/sweep is essentially how far back the fin tilts on its arc. The larger the degree of sweep, the more drawn out your turns will be. This is great for those bigger days with a nice long wall to carve on like when J Bay is cooking. Less fin rake is better in smaller, mushier waves when you need all the pivot out of a fin you can get.
The fin height is basically how far the fin extends away for the bottom of the board. A deeper fin is going to have more hold and stability than a shallow fin. A shallower fin will give you less hold, but once again turning easier, and allow you to cut back the tail of the board more aggressively.
The fin foil is an aerodynamic shape when you look down the line of the fin. Much like the wings of a plane, this foil generates lift under the board. Different foil shapes result in different levels of performance in your surfing.
There are a few of types of fin foils of which each have a few variations. Side fins (on twins, thrusters and quads) are generally flat on the inside or sometimes curved inward, and convex on the outside.
Center fins will usually be symmetrical in shape or have what is known as equal foil on either side. These center fins are found on the back of thrusters (tri fin boards), single fins and sometimes the rear fins on quads.
Fin Cant is the degree of outside angle a fin has in relation to the bottom of your surfboard. If a fin has zero cant, it is positioned at 90 degrees to the base of your board. This setup will be fast down the line, but it lack responsiveness.
If the cant of your fin is larger than 90 degrees, your board will be more responsive through turns. In other words you’ll be able get more drive through your turns.
Fin toe is a bit of a misnomer. It really reflects the angle that your fins are pointing at the stringer of your surfboard. This is only really applicable to the side fins on a board as the middle fin will always be running down the line of the stringer.
Like cant, different fin toe’s dictate the level of performance in your surfing. The greater the angle against the stringer the more responsive your turns will be.
Now that you have a better understanding of all the more subtle surfboard fin variables, we should now cast your focus to one of the most important elements of the surfboard fin – its shape.
Your fin’s shape has a direct impact on how your surfboard is going to perform. From a large single fin all the way through to a quad setup with two larger and two smaller fins, your surfing performance will very much depend on the fin shape.
The flex of the fin that also directly relates to performance. It contributes to your projection of turns, which in turn will initiate your speed down the line and influence control.
A stiffer fin generally reaches maximum flex during a turn and releases quicker, leading to quicker turns. It also tends to have less drive.
A more flexible fin takes longer to reach maximum flex and takes longer to release. It also has greater drive.
Now that you understand the actual size and shape of surfboard fins, now it’s time to explain the different fin setups or configurations. The options you have will be determined by the number of fin boxes in your board. It usually ranges from 1 to 5 fin boxes.
A single fin setup is most common on longboards and longer shortboards. It is the most traditional surfboard fin configuration. Single fin setups tend to result in faster, direct down the line surfing.
By adapting the position of the in will give your riding a different feel. Putting your fin forward will give you a looser feel. Putting it further back will give you more control.
A twin fin or a dual fin setup will make your surfing playful, fun and maneuverable. A twin fin setup will give you more speed on the wave, and are suited to smaller waves. Twin fins offer a longer, more drawn out turns.
In the modern era a thruster is the most common configuration and can be found on a variety of surfboard shapes. The two outer fins are toed in towards the center of the board. These outer fins will be flat on the inside in order to increase water tracking and speed.
The center fin is set back and is closest to the tail. It has symmetrical fin foil. Thruster setups perform well because they combine stability, control, and manoeuvrability. A thruster fin box configuration also gives you options to switch to a twin fin or single fin setup.
Quad fin setups offer speed on the wave by channeling the water to the end of the surfboard and out the back of the tail for acceleration. Having two fins positioned near the rails of your surfboard will also add stability and hold in big-wave surfing when maintaining a high line is often critical. Lastly, quad fins are great for generating drive through turns.
It’s very rare that someone will actually ride with five fins. Five fin boxes simply allow you to mix and match fins depending on your preference and the surf conditions. You have the full range of fin setups available to you when your board has five fin boxes.
Surfboard Fin Brands
What’s very important to note is that in the world of surfboard fins, there is a duopoly at play. There are FCS and Futures fins. Both these companies have their own unique fin system.
FCS fins have the patented two tab system. Traditionally these two tabs were secured into the fin box using two screws on either side of the fin. Recently, FCS has launched the FCS 2 system which eliminates the need for screws.
It’s now possible to install and remove your fins in seconds without the need for any screws or tools, so you’ll be in the line up faster.
Futures fins use a single continuous rail system on their fins. This rail is perforated to keep the fins as light as possible and drive the highest levels of performance. Futures fins are also secured in place with two screws on each fin.
The main difference is that they are secured at each end of the fin, rather than on either side of the fin. It’s important to note that both the FCS and Futures fin systems are not compatible with each other. Therefore when buying a board, or getting one shaped it’s important to know upfront which which fin system you want.