Understanding the different surf fin setups can ensure you maximize your performance when you’re surfing. Surfboard fins are mounted at the tail of the board and enable you to steer the board using your foot. They also help improve its directional stability.
Fins work by influencing two basic forces – drag and lift. Lift refers to the horizontal forces that keep the board in motion. Lift helps the rider
maintain the board’s movement in a particular direction or to turn by using the fins to push against the water.
On the other hand, drag acts like a brake to hold movement back. How much drag is created depends on the fins’ combined surface area.
Before we go into the different setups, it would help if you understand the different characteristics of the fin. The basic ones are:
Size. The size of the fin determines its hold. When the fin is bigger, it has more surface area and thus has more hold and greater control when in bigger surf conditions. On the other hand, a smaller fin gives the board a looser and more forgiving feel but you sacrifice control.
Base. This is the part of the fin that is attached to the board. Longer bases give surfers more drive. Pressure is put against them when the surfer turns, which creates acceleration. On the other hand, a fin with a smaller base creates less drive, but allows the surfer to make short and quick turns.
Depth and Height. Depth measures how far the fin will stick into the water. It is measured from the fin’s tip to the bottom of the board. Since it influences how the board will grip the water as it turns, it also controls how stable it remains. Taller fins have more hold when in the water, giving more control to the surfer.
Fin Sweep or Rake. The rake refers to how far back the fin goes relative to its base. You can estimate the rake by imagining a straight line from the back of the fin’s base to its tip.
Estimate the size of the angle it forms with the line of the base. The smaller the rake, the farther back the tip reaches and the larger the offset from the base.
With a small rake, the fins will keep the board fairly stable while propelling it faster. However, you will have to sacrifice the board’s turnability. On the other hand, a large rake means the fin will not offer as much stability but will provide a tighter turning radius to the board.
Foil. This refers to the shape of the fin. Fins are designed to be aerodynamic from front to back. They are typically thicker in the middle and thinner at the outer edges.
The different shapes determine how water will flow over the surface of the fin. This directly impacts the performance of the board as well as the fin.
There are several types of foil, and their shape determines where they should be placed. Fins that are foiled on one side and flat on the other are usually placed on the sides of the board. Those that are foiled on either side are known as inside fins and are usually placed in the center or used in single fin setups.
50/50 foils are convex and symmetrical on both sides, and are intended to be the central fin in a set up. This foil provides stability and even distribution.
Flex. The flexibility or stiffness of the fin affects the way the board reacts. If the fin is more flexible then it is more responsive to the surfer when they are making a turn. Stiffer fins provide more stability and are more forgiving.
However, fins that are stiff make it more difficult to make sharp turns, and you will end up making sweeping and wide turns. Thus, beginners should avoid boards with stiff fins since they are harder to control.
Where you place the fins on the surfboard is important because they affect how the board will turn and respond. On older surfboards, the fin was permanently fixed through fiberglass or “glassed on.” These days, most surfboards have removable fin systems that allow you to change the fins and move them around to a desired setup.
Here are some of the basic surf fin setups:
This is the classic set up using just one fin. Single fins are usually found in longboards as well as boards intended for beginners.
This set up provides the board with control and stability. The fin used is typically wider and longer so that you can control the board with only the one fin. The single fin is best used in small-medium to small surf conditions, or in medium-big weak, fat waves.
Unfortunately, there is a tradeoff in performance since the movements the board makes are limited to charges in a straight line and sweeping turns. While the single fin is good for slow, smooth turns, it is more difficult to do sharp, quick turns.
A surfer used to modern set ups may feel that the single fin is unstable. This can affect their performance since in this set up, there is less support from the board and control and balance relies more on the surfer.
Also known as Twin Fin, this set up was popularized by Mark Richards. Richards won four consecutive World Championships by using boards with twin fins. It consists of two fins that are mounted near the “rail” or ‘edge’ of the board.
This set up is notable for giving the board extra speed and maneuverability. It consists of two smaller fins that are placed close to the rail.
The Double Fin is best used when surfing in small to small-medium surf conditions. When used in bigger waves, the tail could slide, making it more difficult to bottom turn on bigger waves.
This is the most popular set up used today, and makes use of three fins. Two of the fins are mounted near the rails in a semi-parallel position. The third is placed in the middle of the two, closer to the rear or “tail” of the board.
The two outside fins increase drive by being flat on the inside, while the middle fin is normally foiled. The outer fins are also toed-in to allow the board to turn more easily while speeding it up.
Simon Anderson developed this set up in 1980 after becoming frustrated to the hold he experienced when surfing in big waves. Hence, he decided to add a central fin, which gave the board greater maneuverability and stability than the single or twin fin setups. The Thruster has been credited for spurring the popularity of high-performance surfing.
Two Plus One. This set up also involves three fins in a similar configuration as the Thruster. However, the center fin is larger while the two fins are smaller and are known as “sidebites”. This set up is typically used on longboards since they offer greater stability, lift, and control.
It is best used when surfing in medium size to small waves and in choppy or clear surf conditions. However, this set up creates more drag than a single fin or Thruster.
This set up involves four fins that are placed on the board in a configuration similar to that of the Thruster, but with two on each side. The front fins are usually, but not always, larger than those on the rear. But the rear fins are almost always on the aft and inboard of the front ones.
The surfer has the flexibility to choose the configuration and exact measurements of the set up based on the surf conditions. However, they are best used in medium-sized to small surf since they are effective in generating speed. This set up also allows for sharp and quick turns.
The downside of the Quad is that it may take some time to get used to it if you have been typically been using different set ups. Beginners, in particular, may find it that they will experience a bit of a learning curve when they are first trying the Quad out.
To ensure that you have the maximum flexibility in choosing your fin setups, we recommend you get a surfboard that has a five-fin box. This type of board has five slots allowing you to easily place the fins in the desired setup.
Of course, you can also use all five boxes at once. This setup is known as the Bonzer Five and is similar to the single fin configuration. However, it has the added advantage of providing increased stability when surfing in bigger conditions.
This setup uses a combination of small and large fins. While it has a more inflexible feel than a single fin, you can ride steeper waves more easily.
To sum it all up, which surf fin setups, you should be determined by your skill level and the type of surf conditions you are facing. If you are starting out, the safest choice is to use the standard three fin or thruster setup.
As you become more skilled, you can experiment with the different setups so you can determine for yourself which ones are the best to use in particular surf conditions.