What are a Surfboard Fins?
Surfboard Fins are made of either hard rubber, plastic, fiberglass or carbon fiber. In shape they look like the dorsal fin of a dolphin. The fins are attached to the underside of the surfboard at the tail.
What are Surfboard Fins good for?
If your surfboard did not have surfboard fins, your surfboard would spin uncontrollably. Surfboard fins give you control and grip in the water. They also allow you to turn your board.
In the advanced part of surfing, this can also be done through the rails. But especially for take-off and surfing bigger boards, where the rails are not as engaged, surfboard fins are crucial.
History of Surfboard Fins
The emergence and use of fins was a long time coming. Since the – historically not proven – beginning of surfing, people surfed for centuries without fins. Control over the board was achieved by dragging a foot in the water or holding the rail on one side.
However, this very demanding and complicated technique often ended in wipeouts. It took until 1935 until Tom Blake first attach a fin to a surfboard. After his first surf with the newly developed fin, Blake said: “When I first paddled out the board felt like it was much easier to keep in a straight line, although I thought I might be imagining it. My first wave revealed the truth. Never before had I experienced such control and stability. There was much to work out, but the seed had been sown.”
Blake’s invention fundamentally changed surfing and the style of surfing. In the decades that followed, more experimentation and fins were added. First it was the Twin Fin setup, followed by the Three Fin setup: The so-called Thruster.
Even if in later years the Quad setup was invented, the Thruster is the most used surfboard fins setup in the world. Nowadays all different setups are used by surfers depending on their preference and style of surfing.
Different Surfboard Fin Setups
Single Fin
As already mentioned, the Single Fin is the earliest setup and therefore represents the traditionality of surfing. The Single Fin setup is mainly used in longboards and mid-lengths. I personally recommend everyone surfing a Single Fin at some point, as I find it very important for development in terms of technique and style.
Tip: The fin should be roughly proportional to the size of the surfboard (feet in inches). For example 6’8 (feet) mid-length surfboard should have an approximately 7″ (inch) single fin.
+ speed (less drag)
+ smooth surfing
+ wide, slow turns
– wide, slow turns
– less hold (than more fins)
2 + 1
In the 2+1 setup, the middle single fin is supported by 2 smaller side bites. Mostly used for Mid-lengths.
+ more hold and stability (than single fin)
Twin Fin
Invented by Bob Simmons and made famous by Mark Richards, the twin fin setup is often used in short, wide and flat surfboards. In small waves it is easier to catch waves, generate speed and make it to the next section.
+ more speed (than a thruster)
+ more hold (than a Single Fin)
+ more agility (than a Single Fin)
– less hold (in bottom turns or bigger waves)
– wider turns (than a thruster)
Thruster
The Thruster (three fins) setup is the high performance for surfboard fins. In shortboard competitive surfing I estimate that over 90% of surfers use this setup. It allows a lot of grip and stability even in bigger waves and has the smallest turning arc for aggressive maneuvers.
+ tight, faster turns (high maneuverability)
+ good hold (in bigger waves)
+ all-round setup
+ high performance setup
– slower (more drag)
Quad
Why use a quad (four fins) setup when there are twin fins or thrusters? Because a quad setup combines the advantages of both systems and eliminates the weak points.
+ more hold (than thruster)
+ more speed (than thruster)
+ good for hollow and punchy waves
– less release (board can feel stuck during turns)
– bit more expensive
Different Surfboard Fin Boxes
While there are different setups for surfboard fins, there are also different ways to attach them to the surfboard. We are talking about the different surfboard fin boxes. A fin box is a plug system on your surfboard that allows you to easily insert or remove fins.
Glassed Fins
To be precise, glassed fins are not a type of surfboard fin box. Here the fins are attached to the board in the process of glassing, i.e. during the production of the surfboard, and cannot be removed afterwards. While this used to be the usual way, it is now rare due to heavier transportation and in case of damage.
FCS & Futures
For surfboard fin boxes there are two systems, each named after the manufacturer brand: FCS and Futures. Fin boxes are made specifically for one of the two systems and are not compatible for the other system.
FCS
FCS now has two systems: FCS1 and FCS2. While with the old FCS1 the fins had to be fixed with screws on the side, FCS2 fins can be clicked into the FCS2 fin boxes. Old FCS1 fins can be attached to FCS2 fin boxes with screws and thus continue to be used.
Futures
With Futures, the fins are pushed into the box and then fixed in the back with a screw. If you are still deciding on a fin box system for your surfboard, I would recommend Futures.
Why? I myself have lost FCS2 fins in the past, despite the screws. A, due to the price of fins costly loss. In the video below, Mateus Herdy loses an FCS2 fin during a surf contest and then loses control during the next maneuver. Bummer.
Also, I heard from a shaper that he is reluctant to install FCS2 fin boxes in new boards. This is because he has many surfers and customers who complain that it partly blows out the fins or even the complete fin box during powerful maneuvers.
Tip
Once you have decided on a surfboard fin box system, I recommend you stick with it. This has the advantage that you can easily replace, swap and experiment with the fins between your surfboards.
Single Fin Box
Single Fin Boxes are, as the name suggests, designed for single fins. With this fin system, the fin, which has a small pin, is inserted into the box, slid in and then secured with a screw in the place where you would like to have it.
Surfboard Fin Size Guide
In the table below is listed a recommendation of surfboard fin size according to body weight.
However, these are only recommendations and may vary from surfer to surfer. Depending on the style of surfing, own feeling and the feeling of responsiveness of fins. Best example is for example the well-known pro surfer John John Florence (height: 1.85m , weight: 80kg ). In big and powerful waves he surfs small to medium-sized fins to get more release in his turns. In contrast, he surfs in small waves fins with a fin size large.
The Characteristics of a Surfboard Fin
Base
The fin base is the part of the fin that is actually attached to your surfboard. The fin’s base length is measured at the widest point of the fin, where the fin connects to the board.
The base length affects the speed and maneuverability of your surfboard. A longer fin has more speed and propulsion but less maneuverability. A short base length, on the other hand, is suitable for sharper, tighter turns due to its high maneuverability.
Rake / Sweep
The rake, or sweep, is how far the fin leans back. It is measured from the base to the upper curved end of the fin. The rake has the most influence on the turning radius of your surfboard. That is, less rake, upright fins allow you to do tighter turns. Flatter fins with more rake, on the other hand, have more pivot and create longer more drawn-out turns.
Foil
The foil is the surface of the inside and outside of a fin. The foil changes the water flow over the surface of the fin and therefore has a great influence on the way of surfing. There are a couple of types of fin foils with many variations on each. the most common are: flat foils, inner foils, 80/20, 50/50 (symmetrical).
The middle fin is always symmetrical to ensure stability, while the outer fins are usually convex on the outside and flat on the inside. A flat side provides balance and control while a convex side is ideal for generating speed.
Cant
The fin cant is the inward or outward lean of the fin. A fin that is perfectly straight has no cant. The lower the angle, the faster your bard will be in a straight line but less responsive in turns. In contrast, fins with a high cant will perform better and more responsive when taking a turn.
Flex
The flex of a surfboard fin is how a fin bends when the surfer executes a turn. The flex is strongly dependent on the material the fin is made of. While stiffer fins offer more stability, they also limit maneuverability. However, flexible fins can make it more difficult to control the surfboard.
Toe / Splay
The toe, or splay, is the angle of the fin in relation to the alignment of your surfboard/stringer. On most surfboards, the center fin is fully parallel to the stringer while the side fins are angled inward. This causes the water to push on the outside of the fins, which increases the responsiveness of your board.
Summary
As you can see, surfboard fins are a science in themselves. I encourage you to try different fins and setups. You’ll see how much fun it will be and how much it will improve your surfing.
