Editor’s Note: Last week, we ran part of one of The Definitive Guide to Surfboard Fins. Read that here.

What's in a fin? With so many options do they really make that much of a difference?

What’s in a fin? With so many options do they really make that much of a difference?

Part Two: Construction and Materials in Fin Design
The same way surfboard combinations and design is endless, so are surfboard fin combinations and choices. At we love hearing more about surfer’s experiments and recommendations for fin types for different boards and different waves.

It’s only through experimentation that the best performing fins are going to be found and with so many aspects like materials, construction, cores and design able to be adjusted, it’s no wonder great discoveries are still being made.

However, while experimentation and innovation are great, there are also some proven design aspects that have stood the test of time, and some things we’ve learned to look for when we’re matching our fins with our surfboards…



Australian Steph Gilmore showing the pressure that can be put on your fins and why it’s so important to use high-quality materials and design and construction to improve performance.

Recap of Part 1…
In part one, we talked about flex and fin shape and how they are key elements in making a fin act the way it does.


Fiberglass Fins
One of the traditional fin constructions is fiberglass. The construction of these fins involves laying up multiple layers of fiberglass cloth and resin and then cutting and foiling the fiberglass fin shape by hand. These fins are strong and can basically be made just as stiff or as flexible as you want them to be.

This type of construction is great for traditional surfboard styles like a mid-length or a longboard. You can make any style of fin for anything from a high performance shortboard template to a big heavy D-fin using this method. The attributes of these fins will be as good as your attention to detail when foiling the sides.

Due to their flex properties and lightweight nature, fiberglass fins are a great option for shortboards. However, the drawback is how long they can take to produce and just how much time, detail and attention needs to go into making these by hand.

This is one of the reasons why composite fins are generally more popular for short boards.

fcs fin material construction

Some of the FCS fin constructions shown above can influence everything from drive, flex, control and release.


Composite Fins
Composite fins are fins that use more than one material within the construction. Standard fins that come with most boards are generally made of a basic natural composite.


Once you have all the equipment, it becomes extremely easy to produce a large number of these fins. The technique for making these fins is called Resin Transfer Molding, or RTM. This process involves injecting resin with fiberglass into a mold that results in a plastic-like fin that’s both lightweight and strong.

While these are great to produce en masse, you definitely can’t quite get the right flex properties that you want in a fin.

G10 Materials
The next progression up from the basic Natural Composite fin would be a fin made using G10 material. The G10 method is widely used throughout several industries, and uses an epoxy and fiberglass laminate. Fins made this way are both flexible and extremely durable. G10 fins are generally a little more stiff and have controlled flex that results in plenty of drive and control.

So how could fins get more high-tech? This is where we start to play around with things like cores and high grade materials like carbon and kevlar.

Performance Core Fins
You can make the core of a surfboard fin out of almost any material you want. The most popular core at the moment is a honeycomb/hexagonal design thats made from lightweight and extremely strong materials. This type of design provides a unique stiffness and flex pattern through the fin in a super lightweight construction.

This process generally uses the standard RTM method mentioned above and has standard fiberglass and resin wrapped around the core. This performance core style of fin has changed fin development forever. However, it doesn’t end there.


It’s the exploration into ultra high tech materials that make this style of fin progress to the next level.

PC Materials and fin flex
Carbon, kevlar and texalium can be used either individually or in combination and provide very different flex patterns.

Different “skins” have different strength to weight ratios and need to be placed strategically on a fin. This results in a wide variety of fin flex patterns. Each different design, construction and type of material is going to store and release energy generated through your turns or when driving down the line in very different ways.

These kinds of constructions and crazy materials experimentation are generally found in ultra high performance fins and–like we’ve said all along–can be combined in as many different configurations as you can think of.

mick fanning an john john florence

Mick Fanning with his FCS II dual tabs and John John showing his single tab Futures Fins.


In Summary…
Choosing fins, like choosing surfboards, should be an ongoing thing as your surfing progresses and is nearly unlimited in the combinations you can try out.


The constructions and materials mentioned above only scratch the surface of what is possible in experimentation and fin design. There are an unlimited amount of combinations that can be used for the cores and skins of fins that all play around with flex patterns, weight and the strength of your fins.

With all of these various materials combined with foils, shapes, design and everything else, you can see why the experimentation of surfboard fins is going to continue on for some time!

So next time you grab your board and throw in your usual fins, try changing them up. Use something different… you may just find the combination that changes the way you surf forever.

For more information on fins and surfboard recommendations, check out the Board Engine on


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