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Why do Surfboards have fins?

The surfing that we see today was made possible by one mans curiosity to make the surfboard more stable and maneuverable but how did we get here and what does the surfboard fin actually do?

You want to know more about fins? You're in the right place. Everything you need to know, to get up to speed on the surfboard fin.

So, you are looking to buy your first set of surfboard fins.


mickey febuary thruster fins aquiva surf captain fin

You just bought your very first surfboard and are left wondering, where the fu*k are the fins?! 

Well before that, what exactly do fins on a surfboard do and what kind of fins do I need? 

The surfboard fin is extremely important when it comes to the surfboard's stability, performance and overall feel when riding a wave. Each surfboard requires a certain fin design or shape to compliment and adhere to the size, shape and contours of the surfboard.



  • Be honest about your ability and the waves you frequently ride
  • The latest or most expensive fin doesn't necessarily mean the right fit for you
  • Know what type of fin system or plugs are in your board (more info below)
  • Try heaps of fins! Borrow your mates fins and get a feel for different styles and sizes
  • Combo it up! Play around with different fin sets and unlock something spesh!

Surfboard fins can be extremely personal and that's why shapers and retailers don’t fix any one set to a board when it's sold. What works for one surfboard and surfer isn’t sure to work for another.

Surfers usually build up a solid fin catalogue. Picking and choosing between fins depending on the surf conditions or what board they choose to ride.

There are some basic guidelines to consider when purchasing fins but at the end of the day, talk to your local retailer or that guy on the beach. The right fin can really unlock a surfboard, so get out there and try them all.


surfboard fins aquiva surf

What sort of fin does my surfboard take?

The type of surfboard you buy will determine a particular style of fin. Its not rocket science and some exceptions to the rule can be applied but you'll be sweet by following a few simple steps.

Here are a few fin configurations found on most boards in your local surf shop today.

Common Surfboard Fin Setups Are:

  • Single Fin

  • Twin Fin

  • Thruster

  • Quad Fin


single fin aquvia surf twin fin aquvia surf

thruster fins aquiva surf quad fin aquiva surf


Not so Common Surfboard Fin Setups are:

  • Bonzer Fin ( 3 or 5 fin setup)

  • 2+1 Fins

  • Duo (developed further recently by Neal Purchase Jnr)


    bonzer aquvia surf two plus one surfboard fins aquiva surf

    duo fin aquvia surf

    Common Surfboard Fin Systems Are

    • FCS & FCSII

    • Future Fins

    • Glasson Fins

    • Single Fin Box (longboard & mid length fins)


    fcsi aquiva surf fcsii aquvia surf

    future fins aquiva surf surfboards glass on fins aquiva surf surfboards

    single fin box aquiva surf

    The History of the Surfboard Fin

    Before surfboard fins, the ancient Hawaiian royal class used to ride massive Olo boards. Long, solid or sometimes semi hollow wood surfboards. The Hawaiians would wait for large swells to roll into Waikiki, unable to turn or carve, their objective was to ride these crafts to the beach, occasionally dipping their toes or feet into the water to slightly manoeuvre the boards from obstacles in their path.

    early surfing aquiva surf

    In 1935 Tom Blake attached the very first fin to a surfboard. Blake, considered to be the founding father of surfing, not only discovered the stability of the surfboard fin but would also invent the hollow surfboard and water housings for surf cameras later on in his life.

    tom blake surfboard fin aquiva surf

    The large Olo surfboards were extremely heavy and unpredictable when riding these waves, so, Tom Blake asked a local speed boat skipper about the keel looking thing on his boat. The Skipper explained to Tom that it was a Skegg. Skeggs which are found on speedboats, are used for stability during a turn. So, when Tom found a washed up speedboat one day on a Hawaiian beach, he “borrowed” the skegg and attached it to his surfboard.

    At first he wasn’t all that impressed with the 4” by 1ft wide fin but as surfboard designs progressed over the next 10 years, the fin really came into its own and became an integral part of turning and surfboard design.

    aluminium keel fin surfing aquiva surf

    As surfers began to look at riding the ‘green part’ of a wave for longer, the surfboard fin got smaller with knife-like edges to pierce through the water. George Greenough would be credited for creating smaller, thinner surfboard fins with more flex. These fins allowed the surfer to pivot tighter in the pocket and get to places never seen before on a wave.

    greenough single fin aquiva surf

    Other shapers and creators would later take on variations of the fin like Bob Simmons in the 40’s. Bob's classic half circle fin designs made famous on his Simmons boards are still popular today. These were the first recorded twin fins in surf history.

    bob simmons keel fin aquiva surf

    A few decades on, Steven Lis’ fish design in the 70’s would be the next evolution of the surfboard fin. Originally kneeboards, Lis’ designed twin fin eventually made it to stand up surfboards and was later explored further by Mark Richards with world title success.

    steve lis fish aquvia surf

    Surfers were still riding single fins in the 70’s but Mark Richards changed that. Not only did he re-invent the twin fin but he was a fierce competitor and would win 4 consecutive world championships in 79, 80, 81 and 82, silitifing the twin fin design into the history books.

    mr twin fin aquvia surf

    In the late 70’s, Australian surfer Simon Anderson was surfing through the Australian titles and making a name for himself in Hawaii. Dubbed the proving grounds, Hawaii is the place surfers make any kind of name for themselves but it was hard back in the 70’s as the Hawaians dominated these lineups.

    Simon demanded a lot of respect for his surfing but he still wasn’t quite satisfied with the performance he was getting from his MR Twin Fins, especially when the surf got big the board would skip out. 

    A surfboard caught Simon's eye, who at the time was shaping his own boards. This particular surfboard was a twin fin but with a small half moon fin in the rear. Anderson would then create 3 fins all of the same size and position them on the tail of his Energy Surfboard. He would then coin the phrase “Thruster” and history was changed forever. In 1981 he showed the world for the first time the Thruster Fin, winning the world championship with monumental performances at HUGE Bells (The biggest it's ever been) and Pipeline.

    simon anderson thruster aquiva surf

    Even to this day, the Thruster fin is used in just about every surfboard at the beach and under the feet of every pro surfer in competition.

    So what makes a surfboard fin work?

    The first surfboard fin was designed for stability but as surfboards evolved, so did the fin. The modern thruster fins provide stability, lift and acceleration with the right combination of foil, cant, toe, rake and volume. All these elements work cohesively together to make a surfboard extremely responsive. We here surfers say “You just don’t have to think about it” meaning, the board and fins are not working against their decisions on a wave and in fact, enhance them.

    *If you’re after the more in-depth science behind fluid dynamics, check out the book Architecture of Planing Hulls by Lindsey Lord.

    So, let's break down these elements to get a much deeper understanding of what's going on under our feet when riding a wave.

    The Foil

    Foil relates to the larger surfaces on each side of the surfboard fin. Most fins with a foil are thicker on the leading edge and thin out towards the rear or tail of the fin. Think of an aeroplane wing with air travelling down the foil producing energy in lift and propulsion, water travels past the leading edge and down the foil of a fin as it accelerates towards the tail. Variations in the thickness and curve of a foil alternates a surfboard's performance.

    There are a few different types of foils including 50/50, 70/30, 80/20. These relate to the amount of volume each side of the fins centre with the longest side or the side with the convex curve is on the rail side of the fin. This directs the water to the outside of the board to eliminate any turbulence caused by this affected water channelling into one another and the centre fin.

    • 50/50 foil
    • Flat foil
    • Convex foil
    • 80/20 foil

    <H2> 50/50 foil relates to an even amount of volume and a mirror like image of foil either side of the centre point. This kind of fin is typically found on longboards and mid-lengths in the form of a centre Single Fin. The other common use for a 50/50 foil is the centre fin in a thruster or 3 fin set up. Other instances may be rear quad fins, Simmons type keel fins and early 70’s lis fish fins or the keel on a hydrofoil board.

    Flat foil, convex foil and 80/20 are typically used as side fins in your thruster, quad, twin fin, two plus one etc.. They provide stability and performance in and out of turns.


    The cant is a word used to describe the fins angle to the bottom of your board. 90 degrees or right angle would mean your fin is extremely straight in relation to the board. What would this mean? The straighter the fin, the faster it will go BUT the harder it will be, to put on rail. This would be fine if you just wanted to go straight but let’s face it, most of us want to turn back to the energy source and make the most out of a ride. 

    That's where fin cant come into play. The more cant the easier it is to turn but too much and you start to create drag. There is always a fine balance between these factors that makes up the perfect board. 

    Most high performance shortboards these days run with fin cant at around 9 degrees. Smaller angles of 5 and 3 degrees can be found on twin fins and the trailing fins of a quad set up. Bonzers and other experimental fin configurations have their own unique take on cant and how it performs.


    Toe is the surfboard fins angle in relation to the stringer. Usually only apparent with out side rail fins and does not apply to a centre thruster fin or a single fin on a longboard or mid-length. The ideal toe for a surfboard sets the base of the fin up on an angle pointing to the nose. Usually falling around an inch either side of the centre nose of the surfboard. This particular setting is decided upon and marked by the shaper in the shaping room. It is usually the last thing a shaper will do to a board, either sign it off or mark the fins. 

    The whole purpose of the toe angle is to alleviate drag while keeping the board responsive through turns and major manuouvors. You might start to get an understanding of how all these things can work cohesively to produce a super sensitive and responsive fin.


    Rake refers to the length of the fin from the base, up through to the tip. A long rake drawn out rake usually has a much thinner tip and is ideal for speed and control. A more upright, or vertical rake has a lot more release. The rake can also increase when you start to play around with the fin series size. For instance, the FCSII MF or Mick Fanning comes in 3 sizes. Small, Medium and Large. You might think, well that just correlates to the size or weight of the surfer, or perhaps the size of the surfboard. Not the case. 

    Remember Foil, well on a large MF fin you have more foil and rake so therefore the fins have more of an impact on the boards performance. If the surfer is heavy footed or what we call a power surfer, then a larger fin can compensate for that extra power in the surfers turns. A smaller fin might not be able to hold and will skip out or slide when the surfer doesn't want it to.

    I noticed this a lot with surfers on the tour. Surfers like Tyler Wright, Owen Wright, Connor O’leary and many others were all riding Mick Fanning's large fins.


    The base of the fin is the surface under the fin that is in contact with the board. A longer base means a larger foil and therefore more water passes over the fin creating more speed and energy. Too long and the board might be much harder to turn. There is such a fine line between all these factors in surfboard fin design, that's why we only see very small shifts between surfers pro model fins. Stepping too far out of this zone and there are drastic effects, not all good ones either!

    The base of the fin that is flush with the bottom of your board is the same for most if not all fins but the way that a fin is fixed to the surfboard varies. 

    FCS uses a twin tab set up with grub screws. These fins can be used in a variety of different FCS fin plugs including FCSII.

    The FCSII fins are again a twin tab system with a locking mechanism on the rear tab and can only be used with FCSII fin plugs.

    Future Fin has a single tab that is nearly the length of the fins base and slots into their patented designed fin plug. There are no variants to the Future Fin tab systems so switching between fins is easy.

    As far as pure strength you cannot beat a glasson fin. Glasson fins have a much more solid connection with the board and are as the title says glassed onto the board with fiberglass. The base of the fin is placed onto the boards fiberglass before the filla coat, so there is a much stronger bond between the two elements. We can go further into the construction though a little later in the piece.

    Fin Tip

    As the name states, the tip of the fin is the last contact water has as it rushes past. The tip can have a big effect on your boards performance through flex. A thinner tip will have more flex in it than say a tip that is quite thick and stiff. Flex is good in and out of tuns. It's how fast the fin can rebound back to its natural state giving you spring out of a turn. Most notable in longboard single fins. A performance longboard will instantly feel a sense of acceleration out of his or her turns on a wave.

    *Hot Tip*

    Look after your tips. Don’t leave your board wax up on the bitumen in the carpark. Chipped tips can hum or vibrate and that means a loss of energy, acceleration and performance.


    Volume is the calculation of all the above. This volume is distributed through the fins foil, rake and base all while working in harmony. It's a good idea to pay attention to the sizes when purchasing a new set of fins. The different sizes and the volume in each size increases or decreases. 

    At the end of the day, try new fins, go up a size, go down a size. It's good to have multiple fins in your arsenal when the conditions change. There is a fin for any kind of wave or condition so get out there and try them all.

    Fin Construction

    Awesome! You’ve made it this far. Let’s get into the latest construction methods used by the top fin manufacturers. The surfboard fin really took on a new direction when the Fin Control System or FCS came onto the scene. I remember it well because I was fiberglassing fins, permanently on to every board that came through the factory. FCS was a game changer! It changed the way we thought about surfboard fins forever. 

    Travelling became easier as you could fit more boards into a board bag without the worry of airlines bustin your fins out! Surfers were now given the option to choose their fins in a retail store and the ability to discover more designs and aesthetics became larger and larger. It seemed like these gimmicky marketing strategies were everywhere. They were all over the pages of our favourite magazines but this weird detachable surfboard fin was here to stay.

    There are many different types of fin construction


    The OG fin composite. Fiberglass fins have been around from the beginning and are still being produced with good results. The way a fiberglass fin is produced is when multiple layers of typically 6oz cloth are fused together using resin. 

    A squeegee is used to drive the air from each layer as it is placed on top till the desired thickness. Once the panel has dried you simply cut out your fin template and begin the foiling process using a variable speed sander and a coarse grit paper.

    Colour can be added in the form of pigments and powder to the resin as it is applied to the panel. Fin companies like Captain Fin started in fiberglass fins but have made a real name for themselves with the quality of workmanship that goes into each and every fin. 


    Honeycomb core fins were a massive leap in fin material tech. Its sole purpose was to reduce the amount of resin used in the build process, making them lighter and more responsive. Resin can be brittle on its own but when used in conjunction with fiberglass and this new hexagonal foam core (that just happens to look like honeycomb) you have the winning formula of strength and flex.

    Aesthetically, honeycomb core exposed fins look pretty sick but at least the tech is backed up with weight and performance stats. More often than not these days, pro and shaper series fins by the likes of FCS, Future, Shapers and other smaller fin brands use this particular core, however it is usually covered with designs…. (NEEDS WORK!!!!)

    Carbon Fibre

    Carbon Fibre construction fins are stronger, lighter and more responsive than standard fiberglass. This particular construction has been proven the world over in many different categories like F1, Aerospace and the like but isn’t really seen on day to day surfboards. Why? We are not sure. Cost could be a large factor but carbon these days is so readily available. Another reason, too stiff. Fins need to have flex and memory to twang (technical terms)  back into shape and propel the surfboard in the intended direction.

    Other constructions on the market include the FCSII Neo Glass Eco.

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