How to Guides

What is a surf fin?

A surf fin is classified as a rudder-like accessory that attaches to the rear underside of a surfboard. Surf fins play a significant role in surfboard performance, and the surf fin finds its origins in America.

Tom Blake was a surfing pioneer who introduced the first fixed fin in 1935. Blake was surfing in Waikiki when he had the idea to attach a metal keel from an abandoned speedboat to his surfboard. The keel was 30 cm (12 in) long and 10 cm (4 in) deep. Blake immediately noticed an improvement in his surfing performance with the added stability and control that the keel provided. He continued experimenting with different fin designs and eventually became one of his generation's most respected surfboard makers.

Today, fixed fins are an essential part of every surfboard, and Tom Blake is credited with revolutionising the sport of surfing.

The modern surf fin is constructed from glass fibre, carbon fibre or plastic. Surfboard fins range from the famous classic 'raked' curved shape to triangular-shaped and stubby or even square fins. 

Your fin type, as well as your fin setup (one, two, three or more fins) and their position on the board, are instrumental in allowing you to regulate your speed and control direction. Selecting the appropriate surf fin is crucial to your performance in the water, making the understanding of the modern surf fin all the more important!


What does a surfboard fin actually do?

Surfboard fins help you to 'steer' your board and can generate drive and speed through turns. As the water moves down the underside of your surfboard, it gets funnelled past your fins before flowing off the tail and lower rails.

Your fin setup determines how stiff or loose your board is; how easily it can change direction. Your fins also determine how much drive (speed and power) you can generate, the types of arcs you can draw, and how much control you have through turns or tube rides. Just small changes in fin type can radically change how a surfboard performs.


What is the difference between glass-on surfboard fins and removable surfboard fins?

Glass-on surfboard fins

Glass-on fins are permanently secured to your surfboard using resin and fibreglass. These fins are slightly more robust and hydrodynamic than removable fins. They can damage your surfboard if ripped off by a reef or kelp and are not interchangeable. Glass fins can make packing a board bag with several surfboards bulkier; unfortunately, airline baggage handlers frequently break them.


Removable surfboard fins

A removable fin is an interchangeable fin system that allows you to replace and combine several fin types to suit different surfing conditions or styles. The two most common removable fins of today are FCS and Future Fins. Removable fins are less prone to breaking, cause less damage to surfboards if they are ripped out, and allow you to pack several boards more securely in your board bag - this has made them more popular than glass-on fins in recent times.


Surfboard fin terminology 

Understanding the various dimensional aspects of surfboard fins will help you to choose the right fin setup.

Fin Base

The length of the base fin that touches the board. The longer the base, the more power or 'drive' is created when you apply pressure to your fins, but it will be harder to turn. The shorter the base, the less drive there will be, but more manoeuvrability.

Fin Depth

Fin depth refers to a fin's height, meaning the distance from the base of the fin secured to the board to the tip of the fin. The deeper the fin, the more it will act like a stabilising rudder in the water, but it will be harder to turn. The less depth, the less stable it will be, but easier to manoeuvre.

Fin Rake

'Rake' or 'sweep' describes the distance the back of the fin protrudes in an arc (for example, dolphins have more fin rake than shark fins). A longer rake means more stability and the ability to do longer turns, and less rake means less stability but more ability to apply rapid direction changes.

Fin Foil

The convex curve on the side of a fin, 'fin foil,' is thickest through the centre and tapers towards the edges. Like an aeroplane wing, fin foil creates a 'lift' through your tail as your board accelerates and enables you to control your speed - the more foil in a fin, the greater this effect.

Fin Cant

Fin cant refers to the angle a fin is splayed out from the board past 90° (a perpendicular fin has zero cant). The less cant in a fin, the more speed it will generate, but the harder it will be to turn. Conversely, the more cant a fin has, the slower it will make the surfboard, but it will be far easier to manoeuvre.

Fin Flexibility

All fins have some flexibility, from thicker, rigid glass fins to carbon and composite fins to cheaper plastic removable fins. The more flexible a fin, the easier it will be to manoeuvre your board. However, watch out for fins that are too flexible, as these can create drag and make your board spin out of control during sharp turns.

Fin Size

Fin size refers to the fin's surface area. Your weight is used as a guideline to determine which fin size is best for you. Larger fins allow for more stability and offer more drive, but are stiffer. Smaller fins are looser and allow for more manoeuvrability, but are harder to control.


Which is better: FCS vs Futures Fins?

Like any competing products, FCS and Future Fins have pros and cons, most of which are primarily up to individual taste and personal requirements. Futures and FCS both have signature fin templates with various athletes and shapers and have a massive range of fins for all surfers. FCS are most known for their removable fin system (FCS II), which allows for fast and easy changing of fins on the go; without needing any tools, this makes travelling much more straightforward.

On the other hand, Futures fins feature a simple fin box held in place with one grub screw and is often favoured by surfers who have no interest in removing their fins consistently. There is no superior fin system, and many surfers have boards in both FCS and Futures.

Which should you pick? 

Here at our shop in Hayle, we have a great range of both FCS and Futures demo fins available for daily hire. Why not come and experiment to find the perfect fin for your needs? And if you don't have a board, don't worry. We have a massive range of demo boards available in both fin systems.


Different fin setups & shapes - pros and cons to each

Fin configurations typically range from one to five fins. Below, we take a look at the strengths and weaknesses of the main fin setups you are likely to encounter:

Single fin setup

Strengths - Single fins are always in the centre of the board. The single fin is foiled on both sides and larger than other fins. Single fins have increased stability, control and speed and are recommended for beginners.Single fins are popular on longboards and also commonly found onmid-lengths.

Weaknesses - Single-fin surfboards can be hard to manoeuvre, and larger fins can cause drag, slowing the board down. A single fin setup makes sharp direction changes challenging, and they also don't perform as well in tiny or messy surf.

Twin fin setup

Strengths - With no 'stabilising' centre fin, surfboards with twin fin setups are incredibly manoeuvrable. Twin fins have reduced friction across the overall fin surface area and can make a surfboard go exceptionally fast, especially in clean surf. Bonus - they're great for boosting airs! 

Weaknesses - Due to the lack of a stabilising centre fin, twin fins have a reputation as unstable and hard to control. Requiring a unique technique to surf well, they are challenging to ride, especially in bigger waves, and are better suited to intermediate to experienced surfers.

3 fin (Thruster) setup

Since the invention of the Tri-fin Thruster by Australian surfboard shaper Simon Anderson in the early 1990s, the three-fin setup has been the most popular in shortboards.

Strengths - With two leading side fins and one trailing fin in the centre, the thruster fin setup employs the best of the single and twin fin, matching stability and speed with manoeuvrability. A fin system can be customised with different fins for varied surf conditions.

Weaknesses - In some surf conditions, the trailing fin can create more drag than it can generate speed, slowing the board down. A three-fin setup is also not always the most ideal for certain surfers or surf conditions, such as a long soft point break.

Quad fin setup

Strengths - Quad fins are usually more stable than a twin fin but still fast and highly manoeuvrable. Used with mid-length boards with a lot of volume or fish shapes, quad fins are a lot of fun to surf. They can also be suitable for surfers progressing from the intermediate stage of their surfing wishing to explore new boards and surfing techniques.

Weaknesses - Quad fin surfboards require great skill to surf well. They are often so fast they are difficult to control through high-speed turns and can spin or slide out quite quickly. Though top professionals use them in large surf or big barrels, average surfers tend to use them only in smaller, fun beach break waves.

Twin+1 fin setup

Strengths - The Twin+1 fin setup sits between a thruster and a twin fin. This setup intends to tame the looseness often associated with twin fins by adding a smaller stabilising centre fin.

Weaknesses - Introducing a centre fin reduces the overall speed of the board, which is the defining characteristic of most twin fins. Some boards are designed to be thrusters and will not perform well with this setup.

2+1 fin setup

Strengths - An evolution of the classic single fin, a 2+1 fin setup complements the single fin with a set of side bites for additional grip and drive, allowing for more fin options and increasing the board's versatility.

Weaknesses - The amount of options available opens up the possibility of creating a fin setup unsuitable for the board's natural characteristics, either making the board too stiff or too loose.

Bonzer fin setup

Strengths - A bonzer is a hybrid type fin setup encompassing a single fin with two or four smaller side fins. This setup can accentuate the best attributes of singles, twins and thrusters.

Weaknesses - Like the twin and quad, the highly sensitive bonzer setup is arduous to surf; most newcomers to bonzers find them hard to ride at all. These fins are also most commonly glassed in, which is prone to breakages and cannot be interchanged.


Ability & Size: A Surf Fin Guide

What surfboard fin is best for me? What should I look for in choosing a fin setup? When deciding which fin setup to use, you need to factor in the following.

Your Size

Your height and weight determine your surfboard dimensions and fin configurations. The rule of thumb here is that the taller and heavier you are, the bigger fins you will need. 

Here are the recommended fin sizes based on your weight from FCS and Futures.

FCS Size Guide:

  • Extra Small: (Under 55Kg / 120 Lbs)
  • Small: (55Kg - 70Kg / 120 - 155 Lbs)
  • Medium: (65Kg - 80Kg / 145 - 175 Lbs)
  • Large: (75Kg - 90Kg / 165 - 200 Lbs)
  • Extra Large: (Over 85Kg / 190 Lbs)

Futures Size Guide:

  • Extra Small: (34-53kg) (75-115lbs)
  • Small: (48-70kg) (105-155lbs)
  • Medium: (65-88kg) (145-195lbs)
  • Large: (80kg+) (180lbs+)

FCS fins are categorized by their "fin family" range, each "family" of fins are designed to excel in a different range of surf conditions and suit different styles of surfing. Check out the video below for a detailed run-down of the FCS range of fins and different construction materials.

 

Futures Fins are categorized by their ride number, this gives you an idea of the performance characteristics of each fin template. In basic terms, the higher the ride number the faster the fin speed generation whereas a lower ride number offers more precise control speed control, balanced fins sit right in the middle making them great all rounders.


Your Ability

How well do you surf? How surfing fit are you? It would help if you were honest with yourself. Using the appropriate surfboard/fin setup at each stage of your surfing journey will mean you will master the basics of surfing and progress more quickly. 

Overestimating your ability will mean you are riding the wrong equipment and will slow your progress – and can even be permanently detrimental to your surfing.

Beginner surfer

A longer single fin, usually on a longboard, is the best for beginner surfers. But a standard solid thruster setup (big fins with more rake and less cant) on modern longboards and surf school pop-outs is also suitable, especially if you are learning to surf at gentle beach breaks.

Intermediate surfer

Unless you want to continue surfing on a longboard, you should advance to a standard thruster shortboard when ready. As you become more competent in different kinds of surf (big waves, barrelling reefs, or point breaks), you can also start experimenting with different fin setups.

Advanced surfer

An advanced surfer who understands how fins work can best use them and ride in all types of surfing conditions. Generally, advanced surfers will have a range of fins for their quiver of boards, which can be adapted as twins, thrusters and quads for a wide variety of surf.

Wave Types

The wave conditions you intend to surf also play a role. Do you generally surf onshore, messy waves – or clean, bowly peaks? Do you like to tackle big surf or head up the coast to your favourite down-the-line point break?

Like surfboards, surfboard fins are also designed with a specific wave type or range of conditions. Fins that are designed for fast, powerful surfing in bigger waves will have a much different design than fins designed for loose and responsive surfing in smaller waves. The wrong fin on the wrong wave could see you losing the tail on a big open face or struggling to turn on a small punchy beach break.

Remember, the beauty of a removable fin setup is that you can change your fins for different types of waves, expanding the scope of the kinds of conditions you can tackle.

5 Surfboard fin maintenance tips

  1. Sand down your fins. Fins often get nicks or scratches from the reef, rocks etc. Sanding down any rough edge with a high grit water paper will maintain their condition and performance and prolong their lifespan.
  2. Make sure your fin screws and screw holes do not have any sand in them when you are changing fins or fin screws by cleaning, blowing in, or on them. Granules of sand or dirt strip the thread, making them impossible to tighten or loosen.
  3. Keep your fins in a separate pouch away from your wax, sun cream and anything else that might dirty or damage them. Nothing is worse than trying to screw in a pair of fins full of dirt or wax.
  4. Use sandpaper to sharpen blunt fin keys. File down the end of your fin key on a piece of high grit water paper to sharpen it up if it has started to strip on end.
  5. Always carry more than one new-ish fin key and a spare set of fin screws. You never know when you – or a fellow surfer – might need them!
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