Ultimate guide: How to choose surfboard fins

It's important to know what you're looking for in a surfboard fin, in this article, we're going to take an in-depth look at the various types, brands, and setups for your board. It's important to know what you're looking for in a surfboard fin, in this article, we're going to take an in-depth look at the various types, brands, and setups for your board.

Surfboard fins are a crucial part of any surfers success on the waves, ensuring you have chosen the right fins that will work for you and your board, will make all the difference, whether you're looking at size, riding style or, wave size.

There are two types of fins, and understanding these are important before moving forward, it is important to distinguish between glassed-in and swappable fins. 

Fin for a fin

Photo Credit: Fin for a fin

Glassed-in or Swappable (removable) fins

The two options are fairly self-explanatory glassed-in fins are laminated into the board at the point of construction. 

A glassed-in fin might be smoother, and sounder than a removable fin, however, that's not all good. 

Photo Credit: Surfy Surfy

They're also much harder to repair and simply don't offer the versatility of a removable fin due to its flex from the base.

More commonly nowadays are boards with removable fins, these are surfboards that have had a "box" installed and glassed over. 

This leaves a space for a detachable fin to be fitted into and screwed in. 

Different brands offer different boxes, but there are two major and notable options. FCS and FCS II as well as, Futures.

Depending on your box, will depend on the fin, these are easy to install and only require a fin key ( tool ) to add, remove or replace your fins depending on your style, wave size, speed and a variety of other variables. 

Note: Be careful with your fin box, once damaged, you're in for a real headache in repairs for your board, be gentle, don't use aggressive force, and don't over tighten your screws. 

Box Types & Compatibility

Although longboard boxes are typically cross-compatible with one another. For all other boards, you will more than likely find your board comes equipt with one of the following three box types:

Dual Tab (FCS & FCS II ) Fin Boxes

FCS is a system originally designed in the early 1990s and is the most widely used and accepted fin system on the market and used globally. FCS standing for Fin Control System was started in Australia and took off due to it's easy to use nature and first to the market idea.

Photo Credit: Blink Surf

Both the FCS and FCS II range come with dual tabs and backward / forwards compatible making it the ideal option for your board. 

As you can imagine being a dual tab system there are 2 tabs on each which are screwed to the board with the included screws. However, using the FCS II box with an FCS II fin there will be no need for screws, as the "keyless" technology allows your fin to fit into the box without any tooling by simply "snapping" the fin into place.

Single Tab (Futures) Fin boxes

The other major box system is the futures system which, unlike the dual tab system the futures fin offer a single tab base which stretches the entire length of the box for a stronger fit. Easy to use grub screws hold the fin into place.

Created in 1996 by the Longo brothers who tackled complex aerospace parts, put their love of surfing to good use when they created a break-through in surfboard fin systems.

Futures fin box

Photo Credit: Global Surf Industries youtube

Choosing your fins

Although this seems daunting with hundreds, if not thousands of variations as well as your box system and the number of fins needed, this step isn't and shouldn't be scary.

Follow our information carefully, and by the end, you will know exactly what fins are best suited for you.

The very first step in determining your perfect fin, is starting with your body weight and the number of fin boxes on your board.

Fin Size

Depending on your weight, will depend heavily on the size fin you use, start by using accurate scales to determine your weight range. 

Once you have determined your range, use the table below to identify your size fin, write this down. It will be important moving forward.

Size Weight (KGs) Weight (lbs)
Grom <45 <100
XS <55 <120
S 50-70 105-155
M 65-90 145-195
L 75+ 165+
XL 90+ 190+

Fin Configuration

Now, the nitty-gritty technical stuff!

Once you've determined your weight range and fin size accordingly, the next step is understanding your board's fin configuration. 

Looking at the base of your board near the tail, you'll see your fin boxes, this will likely range from 1 to 5 boxes, the more common setups are Single, Twin, Thruster, and Quad. If your board has 5 boxes this is for you to make the choice depending on your style.

Single Fin

Single fins are typically found in longboard configurations and older traditional surfboards. The single fin setup is ideal for surfers that want a more relaxed surfing experience, turning is limited, meaning it's ideal for fast, straight shot surfing offering control, stability, and predictability on your board. Most single fin boxes allow you to make adjustments to fin positioning allowing forward and backward movements for different experiences.

Twin Fins

Also known as dual fins will make your surfboard not only more playful and fun but maneuverable. Twin fin configurations, however, are not ideal for large wave riding and typically found on shortboards to enhance the riders speed. Dual fins also offer a longer more drawn out turn and skateboard-like feel.

Thruster / Tri Fin

These are by far the most commonly and widely used configuration and can be found on all boards shapes and sizes. The who outer fins are closer to the middle of the board, these are angled towards the boards center or "Toed-in" and can be flat on the inside in order to increase water tracking and speed. The inner centered fin is asymmetric fin which means its the same on both sides. Thrusters perform extremely well as they add control, , and stability whether you're a seasoned professional or a complete amateur.

Quad Fins

Quad fins are the perfect fin configuration for smaller surf, offering greater speed by channeling the water to the end of the board which offers a much better acceleration. The two outer fins offer great stability whilst the two inner fins offer more of the speed. Quad fins are great for generating drive through your turns.

5-Fin systems

This is becoming a more commonly used system due to it's flexibility. 5 fin systems are not designed to have all 5 fins used, but offer you the option to have a quad fin setup, thruster setup, twin or single. The fin positioning allows for your own configuration based on your desired surfing style. Typically the better setup for those who surf in varying surf conditions and styles.

2+1 Fin

Typically found in a longboard the 2+1 fin system allows for 2 fins on the outer sides and a single fin in the center. The difference in this a pose to a thruster is the larger center fin box allowing the larger longboard fins to fit and be adjusted to the surfers desired positioning. A popular option for eggs, funboards, SUPs, and Logs.

Dimensions and Geometry

The nitty gritty of fins! a very important aspect of fins all surfers and enthusiasts should know and understand like the back of their hand. 

Understanding the important measurements such as sweep, toe, base length, foil, flex, height, and cant are all just as important as one another.

Sweep ( Rake )

When looking at the sweep or otherwise known as the rake of a fin, is how far the front edge of a fin arcs backwards. Rake is the measurement that determines how far back a fin curves in relation to it's base. This is what propels the board, the smaller rake fins will offer greater speed and will be more predictable but less ideal for short, fast turns. Large rake fins offer you a "squirrelly" yet playful experience whilst letting you make tighter turns.

Toe/Splay

Often defined by the manufacture of the board, the toe or splay of a fin system is the angle of which the side fins are in relation to the boards central stinger. Often side fins are referred to as "Toed-in" with the front of the fin angled towards the middle of the board. This allows water to pressure the outside fins which will ultimately increase your responsiveness. 

Base/Length

The widest point of a fin is the base, giving the fin strength and is often the part that sits flush with the base of your board once installed. The length of the base will effect the boards responsive behaviours in turns. The longer base creates trajectories for water to propel past, which creates gives you a faster ride. For sharper, more maneuverable fins go for a shorter base. 

Foil

Foil is one of the more important aspects of your fin, referring to the shape of the outside and inside faces of your fin, thinnest near the tip of your fin, and thicker near the base. Altering the flow of water over the fin surface has a direct impact on the performance of your fins and board. Your central fin will always be symmetrical and convex on both sides, this is often referred to as "50/50", this offers even distribution and stability. Outside fins are typically convex on the outside faces and flat or curved inwards on the inside. The flat inside creates a solid balance of control, speed and maneuverability, whilst a curved or concaved inside maximizes lift and minimal drag, more ideal for speed and fluidity.

Flex

The fins flexibility or lack of flex significantly impacts the way your board reacts, a more flexible fin offers a more playful and fun experience, where a stiff fin will offer you greater speed on hollow waves. Higher end fins come with both soft and stiff flex patterns being stiff at the base and softer at the tip. 

Height/Depth

This is the measurement from the base of the fin, to the tallest point at the tip, The varying heights of fins is designed to change your boards stability and grip through turns. If you're looking for control and to surf in a more relaxed manner a taller fin is the way to go, shorter fins don't give grip the water like taller fins, meaning more experienced riders can maneuver the board more freely.

Cant

Cant is the degree in which the fin sits in relation to the boards base, for example, a fin that is straight up/down has a cant of 90 degrees, this makes your ride faster by carving through the wave more freely. Anything outside the 90 will increase the boards responsive behaviours through turns. The less cant allows for greater acceleration and drive. 

Conclusion

The bit you have all been waiting for, which fin is best for you? Start by determining what type of waves you're riding on and the type of surfing you do, this will determine all the above and offer you what you need. As each surf style and save varies, so will your selection of fins.

Additional Observations that help with your decision:

  • A stiff surfboard, paired with smaller and more flexible fins will give you a much more playful experience
  • Surfboards that are built softer, and looser will be faster and offer more drive when fitted with stiff, larger fins with more sweep.
  • Your fins location in relation to the tail or back of your board will effect the feel which creates a loose feel, further back will offer you more control and hold.
  • If your board has a wide tail, it will work better with larger fins
  • If you have a short surfboard, and riding larger waves. You will benefit from larger fins.

We obviously hope this guide has helped you determine what fin is best suited to your surfing style, and board. If you have any questions, please don't hesitate to ask, shoot us an email and we will be more than happy to guide you through picking out a fin.