The fins you put in your favourite surfboard can play a huge role in your performance on that board. Some people even claim that your choice in Surfboard Fins can impact up to 40% of your performance. With so many different boards and different conditions, it’s important to think about different fins and fin setups that work the way the shaper intended the board to be ridden.
The best thing is, just like surfboards, fin design, templates and experimentation is almost endless.
Before you dive head first into testing, it’s great to know a little bit about how each characteristic can impact your surfing performance. Let’s start with the basics.
Craig Anderson showing some extreme release on his signature Futures template in Blackstix construction. That is perfectly tailored to the way he surfs.
The size of the fin is going to impact your performance. A larger fin generally will have more hold and also provide plenty of control in bigger surf. A smaller fin, on the other hand, is going to be more forgiving and loose but you’re going to sacrifice a lot of drive and control in bigger surf.
Difference between the FCS IIFilipe Toledo Large template and the Filipe Toledo Medium. Same size base different fin area (mm²).
The part of the fin that is actually attached to the board is called the base of the fin or the fin base. A longer (or wider) fin base is going to help with your drive. This translates into drawn out turns. Compare this with a narrow, or short fin base that is going to let you turn a little easier and sharper but without as much of that drive.
The fin depth or fin height refers to just how far the fin extends away for the bottom of the board. A deeper fin in the water is going to have more hold and stability than a shallow fin. The more shallow a fin, you are going to get more release when you throw that tail around through turns.
When you’re looking at the arc of the fin and how far back it tilts or sweeps, you’re looking at the fin rake. The larger the degree of rake, the more drawn out your turns will be. This is great for those bigger days with a nice long wall to work with. Less fin rake and a more upright fin template, means that you’re going to get some more pivot out of them – great on junkier, weaker days.
The more 'Rake' the less 'Pivot' a fin will have.
The degree of surfboard rake or surfboard sweep determines whether you have a looser feeling in your fins or you get more pivot out of them.
The fin foil is an aerodynamic shape from front to back of the fin. Much like the wings on a plane, this foil generates lift under the board. A fin is usually going to get thicker through the center of the fin and taper smaller out towards the edges.
There are a couple of types of fin foils with many variations on each. Side fins (on twins, thrusters and quads) are generally flat, sometimes curved inward on the inside and with a foil on the outside. Center fins will mostly have equal foil or double foil on each side. These center fins are found on the back of thrusters, single fins and sometimes the rear fins on quads. Double foil can also be found on some more traditional twin fin fish models.
Fin foil determines the volume of a fin as well as how the water moves past your fins' sides.
Fin Cant is the degree of outward angle a fin has in relation to the bottom of your surfboard. If a fin has zero cant it’s position straight up and down at a right angle to your board. This is going to be fast in a straight line, but it won’t give you as much responsiveness through turns. If the cant of your fin is larger, your going to gain a little more of that responsiveness through your turns. It means you can maintain some more drive when your board is tilted on the rail.
More Fin Cant means your fins are angled outward in relation to the bottom of your surfboard.
The toe of your fins set up is relating to the angle that your fins are pointing at towards the stringer. This occurs a lot in side fins with the front of the fins pointing towards the center of your board. This can help create pressure on the outside foil of the fin. This in turn, allows you to have a little more responsiveness on your board.
The Toe of a surfboard fin above shows the side fins angled towards the stringer.
Check out some of Mick Fanning’s thoughts on thruster vs quad setups as well as why he chooses to change up his FCS II fin sizes.
Mick Fanning explains how he uses his FCS II fins in different conditions.
Now that you’ve got the basics and all the lingo for fins, you need to understand a little more complicated aspects about how fin shape can contribute to the overall surfing performance.
Your fin’s shape impacts directly on how your surfboard is going to perform. One way to comprehend this is to use a Single Fin for our descriptions.
When you get down to it, thrusters, quads, side fins are more or less variations of these characteristics just in a smaller version.
Flex is one of these characteristics that can directly relate to fin performance.
Flex will contribute to your projection out of turns, which in turn will produce your speed and effect control. More details on flex will follow, but for the purpose of this article, lets look at how flex and shape of fins go hand in hand.
Lets go back to our longboard and check out how it’s going to perform using 4 different fin shapes:
The Flex Fin, the Rake Fin, the Pivot Fin and the D Fin
Different shapes of Single Fins from left to right Flex Fin, Rake fin, Pivot Fin, D Fin.
The Flex Fin (with maximum flex) is a really versatile fin that can be used in just about anything from shorter stubbies to 10 foot nose riders. These flex fins are going to feature a wider base that really tapers down into a narrow tip and doesn’t offer too much drag. When coming off a bottom turn, your flex fin will give you a tonne of projection.
This reflects what we mention earlier where the more rake you have in your fin, the more you can draw out your turns compared with a rigid upright fin template for more pivot in tighter turns.
The Rake Fin (with medium flex) is the next most flexible and sits between the flex fin and the pivot fin along the spectrum. With a wide base like before but with a little more width in the tip of the fin you can see a fairly vertical base that sweeps back towards the end. This combines nicely the projection and maneuverability of the flex fin with some of the hold you get from a Pivot Fin.
The Pivot Fin (with very little flex) is your standard go-to fin-shape for nose riding. You can recognize this fin by it’s full, vertical outline with a wide base. It’s designed to slow you down a little and help keeps the tail further in the water while you’re up on the nose. You can also still step on the tail and pivot (swing) the board around in a relatively tight radius.
The D Fin (no flex) is original surfboard fin. Usually found on more classic, traditional logs, they work well for holding trim down the line, similar to the Pivot fin, the D Fins large surface area helps keep you locked on the nose. However they are much harder to turn in a tight radius.
With a super wide base combined with a super wide tip, these fins get their name from generally appearing in the shape of a D. Sometimes you can find them with a straighter, more vertical forward edge with a curved side aft, and sometimes they’re found with curved edge forward and vertical edge aft.
You would usually place these fins as far back of your board as possible for maximum down the line trim.
Believe it or not, this original photo of Robert August and friends in the 60’s depicts them holding the most modern surf craft of the time.
Surfboard Fins 101
So now you know a little more about fins. With literally an infinite number of surfboard and Surfboard Fins combinations, you’re going to have a good time testing them all out.
Check out Part Two of our Fins Guide below for a better understanding of materials and construction in surfboard fin design.
Part 2 - Construction and Materials in Surfboard Fin Design
Futures Fins giving us a look at the mold for their Alpha Fins. Alpha fins are made up of a carbon fiber compound that is strong and light.
The same way surfboard combinations and design are endless, so are surfboard fin combinations and choices. 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
Kolohe Andino demonstrating why high performance surfing needs high performance fins. Throwing his signature FCS II template to the beach.
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.
Flexible, raked back fins for sweeping turns and some projection can be used, or a more stiff and upright fins to give you sharper turns and a quick release. With a wide range of varying degrees in between both.
One of the traditional constructions found is the fiberglass fin. The construction of these fins involve laying up multiple layers of fiberglass cloth and resin and then cutting and foiling the fiberglass fin shape by hand. These fins are strong. Although the thinner you sand them back the more they will flex. For shortboards the size of the fins means they are usually quite stiff. A stiff fin is the go-to for powerful waves when you want control and stability.
This type of construction is also great for traditional surfboard styles in single fin, and twin fin templates where a more sturdy fin is required. They aren't the lightest fins on the market which is why progressive surfers who want to go above the lip with airs will often choose a different construction.
Connor Coffin demonstrating the right time to use his Futures fiberglass fins.
Grabbing rail for the power carve on a heavy wall of water.
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 on mass, you definitely can’t quite get the right flex properties that you want in a fin.
Dave Rastovich talking about how quad setups help his style of surfing; how material can affect both the flex and stiffness of a fin; and how his Futures Quad Fins incorporate bamboo into the base of the fin to promote strength and extra drive.
The next progression up from the basic Natural Composite fin would be a fin made using G10 material.
The G10 method is widely used through 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 hightech? 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 going around high performance fins at the moment is generally 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.
Now that larger fins can still be a light alternative, surfers such as Ozzy Wright have been utilizing a Twin + small stabilizer fin set up to increase drive down the line into air sections. Seen here in the Texas wave pool with the MR Twin in Performance Core construction.
PC Materials and fin flex
The use of carbon, kevlar, texalium, individually or all together can result in a variety of different 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.
Choosing fins, just like choosing surfboards, provide you with an almost unlimited amount of experimentation and potential.
The constructions and materials mentioned above only touch 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 and you may just find the combination that changes the way you surf forever.