As the original system and fin company, FCS remains at the forefront of innovation and performance through continuous analysis, feedback and development of our products. Fin performance remains our key focus, and with the advancement of Computational Fluid Dynamics (CFD) we’re able to refine our templates and foils ensuring the fins you’re riding meet the highest of standards for a variety of surfing situations.

CFD is a powerful tool that allows us to simulate water flow around fins using computer models. Using CFD eliminates the need for physical prototypes early in the early design process, allowing us to evaluate, compare, and refine fin designs before they ever touch the water.

“When you look at the data, FCS fin foils are superior and more efficient compared to other fins on the market. For the surfer this means faster acceleration from the take-off, more speed between turns, and better feeling of control, even in the most critical of situations”.

CFD & Digital Mission Engineer

“When you look at the data, FCS fin foils are superior and more efficient compared to other fins on the market. For the surfer this means faster acceleration from the take-off, more speed between turns, and better feeling of control, even in the most critical of situations”.

CFD & Digital Mission Engineer

“When you look at the data, FCS fin foils are superior and more efficient compared to other fins on the market. For the surfer this means faster acceleration from the take-off, more speed between turns, and better feeling of control, even in the most critical of situations”.

CFD & Digital Mission Engineer

“When you look at the data, FCS fin foils are superior and more efficient compared to other fins on the market. For the surfer this means faster acceleration from the take-off, more speed between turns, and better feeling of control, even in the most critical of situations”.

CFD & Digital Mission Engineer

While in-water testing with top athletes remains the ultimate benchmark, CFD enables us to combine data-driven insights with real-world performance, helping us to create the highest performing fins on the market. Simulated tank testing has also been used at various stages of the fin development process. By combining all of the resources available to us, FCS can attest to producing fins that perform exactly how they were intended, with the in-water experience for the user being one of total satisfaction and stoke.

Lift  is a force that acts perpendicular to the board.Surfboard fins produce horizontal lift that can be used to build speed, helping you make turns more effectively. If you don’t have enough lift, you’ll find yourself sliding in turns. Fins with different sizes, thicknesses and surface areas will produce different amounts of lift at different speeds. When you increase lift, you also increase drag. If you have no fin or a very small fin, you’ll have very little drag but also very little lift. Bigger fins add lift but also add drag.

Drag refers to the resistance of the fin as it moves in the direction of travel. Drag is inherent to any object as it moves through fluid, such as your surfboard and fins through the water. The most efficient fins are the ones that have the least amount of drag and produce more lift.

The way the water flows around the fin determines its performance. Using CFD, we’re able to view the water flow and measure qualities such as pressure, velocity and turbulence.
 
Surfboard fins experience multiple angles of attack (direction changes) as the surfer rides a wave. And as a result, the way in which water flows around the fins is continually changing. At low angles of attack, where the surfer rides with minimal direction changes, there is a very high level of water attachment around the fin. At higher and extreme angles of attack, where the surfer is making sharp direction changes and/or sliding and releasing the tail, the level of water attachment around the fin is disrupted, and in some cases, cavitation and turbulence occurs around the fin.
 
The various levels of water attachment around a fin play different roles in the overall performance of the fin and surfboard. In some situations, high level of water attachment is needed for grip and speed generation, and in other situations, turbulence and cavitation is needed for the surfer to perform radical turns.

We know the template, or the outline of the fin, has the biggest influence on how the fin will perform. And when we refer to different templates the main reference is to the sweep, sometimes referred to as rake. In layman's terms, sweep refers to how far the fin is ‘leaning’ back, and we measure this angle in degrees.
 
An upright fin with low sweep (Reactor) will turn easily, and in a tight arc. A fin with high sweep (Carver) will turn in a longer arc and provide more control. Using CFD mapping we can also analyse the differences in water pressure between different templates.

Independant CFD testing showed that FCS Fins outperformed competitor fins by providing more lift (hold), less drag and are more hydrodynamically efficient across many different surfing conditions and turning situations. Tests were carried out with the Essential Series templates (Reactor, Performer, Carver) and were compared to competitor equivalent tempaltes of the same shape and size.

The graph above shows the results of CFD testing using the FCS Carver template and our competitor’s equivalent template. You can clearly see the Carver fin has greater lift values and lower drag values during more critical angles of attack up until the point of stalling and cavitation (15 – 20 degrees, typically the release point of the turn).

From these results, and others, we can conclude that FCS fins have more efficient foils compared to our competitors. What that means for the surfer is more speed and better control when performing turns.