Fin Buyer Guide
Surfboard fins come in many styles and changing your fins can drastically change how your board works. Choosing fins that will work best for you depends on your size, ability, board, and type of waves.
Fin Boxes
There are mainly three types of fin boxes. Over the years there have been other types of boxes but most of those are hard to come across now.
Single Tab Boxes
Single tab boxes use a base that inserts the entire length of the fin into the box. There is one grub screw that goes into the front of the fin to secure it in place. There are multiple companies that make single tab, but Futures is the dominant brand, so much that single tab boxes are most times called Futures instead of single tab.
Dual Tab Boxes
Dual tab boxes use a base that has two smaller tabs on the bottom of the fin that insert into the box. There are two grub screws, one for each tab, one on each side. Recently introduced is the screw less system. There are multiple companies that make dual tab, but FCS is the dominant brand, so much that dual tab boxes are most times called FCS instead of dual tab.
FCS stands for Fin Control System. Originally designed in the early 1990s, FCS is the most successful, widely used surfboard fin system in the world. The fins have two tabs or plugs that are secured to the board using set screws. FCS recently launched the FCS II keyless Fin Standard, meaning fins can be installed or removed without a key or grub screws. FCS II is also backwards compatible, meaning you can use your old dual tab FCS fins with the new FCS II system. A compatibility kit is required.
Single Fin Boxes
Single fin boxes are much larger and generally used for longboards. Most longboard fins fit into single fin boxes. There a few variants in length, but there are very few fins. Single fin boxes use a plate and screw to hold the fin in place of a sliding track in the box.
making sure the fins are secure but not TOO tight.
Choosing Your Fins
When choosing fins for your surfboard, you should start with your weight. Choosing the appropriate fin size is the first essential step to choosing the right fins. Once you have decided on a size, examine your board's fin configuration, or fin setup. Your board will be outfitted with 1 to 5 fin boxes.
Fin Size
The following chart is recommended shortboard fin size (not single fin) according to rider weight. If you are in between sizes, consider the type of board or type of waves you will be riding with that particular setup. For example, if you are in between size M and L, you might pick size M fins for your small wave board, but size L fins for your big wave board.
Fin Configuration
Once you’ve decided on your fin size, you need to understand your board's fin configuration. To determine your fin configuration, examine the base of your surfboard near the tail. The number of fin boxes you see is the fin configuration and will likely range from 1-5. The most common surfboard fin setups are Twin, Thruster, Quad and Single Fin. Some boards are equipped with 5 fin boxes so you can mix and match more easily. For example if you have a board with 5 fin boxes, you can ride it as a Thruster, Twin or Quad. We offer some 5 fin set of fins where you have a Thruster set and a Quad sets with the use of mixing up some of the 5 fins. Generally longboards come with a single fin box, some also have two additional shortboard style boxes to set up your longboard with "Sidebites" giving it the 2+1 configuration (2 sidelines and a single fin).
Single Fin
A single fin box is most common on longboards and is the most traditional surfboard fin configuration. Single fins will provide stability, control, and predictability to your longboard. Longboard single fin boxes are long and allow you to move the fin forward for a looser feel, or further back for more control.
Twin Fin
Twin fins can make your surfboard fun, playful, and maneuverable. Two fin setups are not ideal for big-wave riding and are commonly featured on shortboards to enhance their speed. Twin fins offer a skatier feel and longer, more drawn out turns.
Thruster/Tri Fin
Thruster is the most common short board setup and can be found on a variety of surfboard shapes and sizes. Thrusters aka: Tri-fin setups perform well because they add stability, control, and maneuverability that beginners to pros excel on.
Quad Fin
Quad fins can offer speed in smaller surf by channeling the water to the end of the surfboard and out the tail for acceleration. Two fins near the rails of your surfboard will also add stability and hold in big-wave surfing. Quad fins can be great for generating drive through turns.
5-Fin
Five fin configurations are not meant to be surfed with all five fins. Five fin boxes allow you to mix and match fins depending on your preference and the surf conditions. Swap from the freedom of a twin fin, to the traction of a thruster, to the speed of a quad without changing boards.
2+1 Fin
2+1 configurations have a longboard single fin box in the middle, with 2 regular thruster side fin (generally smaller than a shortboard side fin) boxes to each side. The middle box is longer, allowing you to set your middle fin forward or back. This is an increasingly popular fin box configuration on eggs, funboards, longboards and logs. They are generally sold separately.
Fin Dimensions and Geometry
Avery angle of the fin has a name, Sweep, Toe, Base Length, Foil, Flex, Height, and Cant are important measurements of every surfboard fin, and should be considered when choosing your next surf fins.
Sweep (Rake)
The sweep, or rake, is how far the front edge of a fin arcs backwards. Rake or sweep angle is a measurement that determines how far back the fin curves in relation to its base. Fins with a small rake (large offset) 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 and a small offset will allow your board to have a tighter turning radius, but are more “squirrelly” and loose.
Toe/Splay
The toe or splay of a surf fin is defined as the angle of the side fins in relation to the board’s central stringer. Side fins are typically referred to as “toed-in,” with the front of the fin angled towards the middle of the board. This causes water to pressure the outside of the fins, for increased responsiveness.
Base/Length
The base length of the fin is the widest point of the fin, and sits flush with the board once installed. This length can affect how the board will respond to turns. Longer fin bases create trajectories for water to go past – so your surfboard will move faster. If you want to make sharp turns, however, go for a shorter fin base length.
Foil
Foil refers to the shape of the outside and inside faces of your fin, thinnest near the tip and thicker near the base. Foil alters the flow of water over the fin surface and has a direct impact on the performance of your fins and board. Middle fins are always symmetrical and convex on both sides (sometimes called 50/50) for even distribution and stability, while outside fins are usually convex on the outside face and flat or curved on the inside. A flat inside face creates a solid balance of control, speed, and playfulness, while a curved or concave inside face maximizes lift with minimal drag, ideal for speed generation and fluidity.
Flex
The flexibility of a fin, or lack thereof, can significantly affect the way a surfboard rides. In general, a flexier fin will provide a skatier feel on more playful waves, but a stiff fin is ideal in faster more hollow waves.
It is important to note that high end fins can be both soft and stiff – they have flex patterns. Many fins now have a stiffer base for tracking and stability, with a softer tip that make it easier to break your board loose while turning.
As a rule of thumb, stiffer fins work well for all ability levels; they are forgiving, stable and predictable, creating a solid platform for progression and big wave riding alike. Soft and flexible fins are great for making fast, sharp turns and will give freesurfers a lively feel to their board, but are more difficult to control compared to stiff fins.
Height/Depth
The height (often referred to as the depth) is measured from the base of the fin to the tallest point of the fin. This measurement can change your board’s stability and ‘grip’ through turns. For surfers who desire a board that is easy to control, a taller fin will be more forgiving and handle turns in a relaxing manner. Shorter fins do not grip the water as well, but rather allow the board to be more “buttery” when turning, ideal for spin-like maneuverers on the water, for example.
Cant
Cant is the tilt of the fin in degrees, in relation to the base of your surfboard. For example, a fin that is straight up down and in the fin box has no cant (90°) and will likely make your ride faster, while anything more than 90° will increase responsiveness. In order to enhance rider-to-board connectivity and responsiveness, especially through turns, you will benefit from canted fins. The less cant a fin has the more drive and acceleration your board will have but will also be less playful. In turn, the more cant a fin has the looser and more maneuverable your surfboard will feel.
Conclusion
So what kind of fin is best for you? The best way know what fin is best for you and the waves you surf is to try different sets. Just like test driving a car, you should test drive fins in a variety of configurations and types.
Here Are a Few Additional Observations That Will Help Inform Your Decision:
- Stiff surfboards paired with small, flexible fins with a little sweep will add playfulness.
- Soft or looser surfboards will go faster and have better drive when paired with stiff, large fins with ample sweep.
- The cluster or placement of the fin refers to how spread out or how close together the fins will be when attached to your surfboard.
- A spread out cluster results in more control and wider, drawn out turns. A cluster that is closer together results in faster, more responsive turning.
- Fin location in relation to the tail will affect your board's feel. Set forward creates a looser feel. Set further back provides more hold and control.
- Surfboards with a lot of rocker may benefit from larger fins. Ideally, your board’s rocker matches the curve of the wave, which is why a more “rockered” board matches up well with a more curved, “hollow” wave. Larger fins will help you hold onto the steeper face of the wave.
- Surfboards with wide tails operate better with larger fins.
- Shortboarders riding large waves will want a larger, more raked fin.
Glassed-In vs Swappable (Removable) Fins
Glassed-in fins are laminated into the surfboard. As you might imagine, a glassed-in fin might be smoother and sounder than a removable fin. However, glassed-in fins are difficult to repair and do not offer you the versatility of removable fins.
Surfboards with removable fins have “boxes” that fins are screwed into. Removable fins can be added or removed using a fin key and adjusting the small (typically stainless steel) inset screws. Don’t force your fins into the box as that may damage your board or the fin; instead, make sure the screws are loose enough and that your fin is facing in the right direction. Center and outside fins have different shapes, so make sure you are using the right fin for the right box. Once your fins are in place, tighten your screws with the key, making sure the fins are secure but not TOO tight.