The Boardshop Guide To Surfboard Fins

Surfboard Fin Guide

After finding the perfect shape surfboard and nailing the volume and the length, it is important to ensure you choose the right fins to match as these can really affect how your board feels and surfs.

Why are there so many different types of surfboard fins available?

Fin Base, Shape, Size and Configuration all affect how your board will surf. Some boards have different fin box set ups which allow you to experiment with different fin configurations to give your board a different feel.

Read on to learn more about fins and find the perfect fins for every board in your quiver.

Fin Boxes

First things first, you need to determine what style of fins your board takes to ensure that they fit the fins you buy fit in the fin boxes on your new surfboard. People very often pick the best-looking set of fins they can find and unfortunately overlook the base – the fins are no good if they don’t fit!

Currently, there are 2 main fin base types on the market – Single Tab also known as Futures Fins and Twin Tab also known as FCS II Fins.

The predecessors to FCS II fins are FCS I Fins. You can now get infill kits for FCS II fin boxes so you can still use your favourite FCS I Fins in your new board.

If you are unsure what fin boxes your surfboard has please see the images below:

 

Watch Our Futures Installation Video!

 

Watch Our FCS II Fin Installation Video!

 

 

 

Watch Our Single Fin Installation Video!

Set Up Types

You can usually purchase fins in sets depending on what set up you require e.g. twin fins would usually be a matching pair of fins. Check out the images below to determine what set you require for your board.

Single Fins

This is the oldest fin type, most often found on traditional surfboards and longboards and more recently on Mid Length Boards. These large fins allow you to surf quickly but these fins can make boards difficult for inexperienced surfers to control. We recommend moving your single fin towards the back of your board if you find the board feels too loose.

How to size single fins?

It is best to size your single / longboard fin relative to your board size. A generally accepted rule of thumb is to use the same size fin (in inches) as the length of your board (In feet) so for a 9ft board you would use a 9ft single fin. Many surfers recommend going an inch bigger if you are riding your board as a single fin only set up for added control, so if you have a 6ft Mid Length you could insert a True Ames Greenough 4A 7.0 Longboard Fin for example.

2 + 1 Fins

These set ups consist of two smaller fins either side, known as side bites, and one large (single) fin in the centre of your board.

The 2+1 is a very common fin set up, found on an array of boards including eggs, funboards, mini mal surfboards and longboards. The two side bites help to stabilise the board giving you more control, making this set up better for beginner and intermediate surfers.

Twin Fins

Twin fins, also known as keel fins, which rose in popularity during the late 70s, are a matching pair of fins, often found on fish shape boards. These fins are great in large waves, giving your board extra speed and offer more stability and control in turns than single fins. Twin fin boards are renowned for being fun to surf and encourage surfers to use their rails and take lines on a wave that they wouldn’t otherwise if it wasn’t for these fins. 

How to size twin fins?

All twin fins are usually either large or extra-large. We recommend using large fins if you are lighter or extra-large fins if you are heavier (read on to see our fin to weight size chart) but ultimately it comes down to personal preference whether you prefer the feel of a board with large or extra-large twin fins.

Thruster Fins

These 3-fin thruster set ups are probably the most common fin configuration and can be found on most boards from foamies to shortboards. This set up consists of 3 of the same size fins, with two placed further towards the nose of the board and one further back to nearer the tail.

Having 3 fins instead of 2 fins in a twin set up makes the board more stable and easier to manoeuvre as the back fin creates a bit more drag. Simon Anderson came up this popular set up in the 80’s as he wanted to create a better fin set up for high performance surfing in big waves.

How to size thruster fins?

These fins need to be sized according to the surfer’s weight. Please read on and check what size fins are best for you. Of course, some people prefer to go slightly smaller or slightly bigger in certain conditions, so we recommend experimenting to find out what works best for you. It is ultimately personal preference but the weight to fin size chart is a good starting point.

Quad Fins

Quad fin setups offer a little bit of what the twin and thruster. The fact that this setup doesn’t include a centre fin gives your board some added speed and allows you to turn quickly, with a little bit more control than the twin fin set up. This fin configuration is great for generating speed in small waves as the fins increase the hold which also makes the board more stable.

How to size quad fins?

As with Thruster fin set ups, these fins need to be sized according to the surfer’s weight. Please read on and check what size fins are best for you. Of course, some people prefer to go slightly smaller or slightly bigger in certain conditions, so we recommend experimenting to find out what works best for you. It is ultimately personal preference but the weight to fin size chart is a good starting point.

Tri-Quad / 5 Fins

This 5 fin set, also known as tri-quad fins, allows you to experiment and play around with different fin set ups. With 5 fin boxes, you have the option to ride your board as either a quad or a thruster which is great if you want a more versatile board as you are going to be surfing in different conditions.

How to size tri-quad fins?

Please refer to the how to size sections for quad or thruster set ups to get the sizing right for you and your board.

Fin Size 

You will quite often find fins in different sizes Extra-Small, Small, Medium, Large, Extra Large and it can be confusing deciding what size you need.

The fin sizes that you choose should be relative to your weight.

Please see the handy weight vs. fin size charts below for FCS & Futures fins to help you pick the correct size fins.

 

FCS II Fin Size		Surfer Weight (Kg)	Surfer Weight (Lbs)
XS	Extra Small	Less than 55kg	Less than 120lbs
S	Small	55 to 65kg	120 to 143lbs
M	Small / Medium (S/M)	66 to 70kg	144 to 154lbs
	Medium	71 to 75kg	155 to 165lbs
	Medium / Large (M/L)	76 to 80kg	165 to 176lbs
L	Large	81 to 85kg	177 to 187lbs
	Large / Extra Large (L/XL)	86 to 90kg	188 to 198lbs
XL	Extra Large	More than 90kg	More than 198lbs

 

Futures Fin Size		Surfer Weight (Kg)	Surfer Weight (Lbs)
XS	Extra Small	34 to 53kg	75 to 115lbs
S	Small	48 to 70kg	105 to 155lbs
M	Medium	65 to 88kg	145 to 195lbs
L	Large	More than 80kg	More than 180lbs

 

Fin Base

The base of the fin is the bottom part that touches the board. The wider and longer the base, the more driven the board will be and the narrower and shorter the base is the board will have less drive but will be easier to turn.

Fin Depth

The depth of the fin is the height from top of the fin to the base of the fin that fits into your surfboard. This length is how deep the fin sticks into the water. The deeper the fin, the greater the hold and stability whereas the shallower the fin, the board will have less hold and will be easier to turn. 

Fin Rake

The fin rake is the tilt of the fin / how far back the tip of the fin is in relation to the base. The more the fin is tilted, the less pivot the fin will have, and the more upright the fin, the more pivot. If your fins are more upright, they will be better on weaker, messier days whereas more sweeping fins will be better in bigger waves.

Fin Foil

The foil is the shape of the side of your fin – how much it sticks out from the centre. This shape affects how the water moves past your fin and it helps to create a bit of lift underneath your board.

Flat foils: Flat foils are usually found on side fins. These are flat on the inside and have a curved outer edge. This gives the foil drive, pivot and hold and provides a consistent, reliable feel over a wide variety of conditions.

Inner foils: These foils consist of a curved outside foil and a slight concave inside foil. Inside foils provide more lift when the waves are slower and less powerful. We wouldn’t recommend these fins for faster waves though as they tend to produce more drag in faster waves.  

80/20: These 80/20 foils are more curved on one edge than the other, hence the name. The curved edges result in an increased speed, smooth transitions, and feel consistent in an array of conditions. You will most often find these fins used as trailers for Quad setups.

50/50 (symmetrical): These symmetrical foils are most often used on centre fins where both sides are convex / curved, this results in even water flow on both sides which creates stability and control.

Fin Cant

The Fin cant is the angle of the top of the fins in relation to the board – how far they are angled outwards. A fin with zero cant is straight up and down whereas a fin with more cant would be angled slightly outwards.

The more cant the fins have, the board will perform better and be more responsive when turning, whereas the less cant a fin has, the faster the board will be when surfing in a straight line.

Fin Toe

The fin toe is the angle of the fins towards the stringer / centre of the board. Often the front end of side fins will be pointed slightly towards the centre of the board to create pressure on the outside foil of the fin which makes the board feel more responsive.

 

Fin Shape

Once you have decided what size fin you need, your next decision will be what shape to go for. You will quickly realise that there are several different shapes available and each of these fins offer something slightly different depending on how you want your board to surf and feel.

Longboard single fins are a good example as there are several different shapes available that will each bring something different to your surfing.

Flex Fins

Flex fins are great for making your board easier to turn. These fins have a solid base and then thin out towards the end of the fin which helps to reduce drag. These are a very common fin for longboards, but they can be used on a variety of boards from eggs to mid lengths or 9ft plus logs.

The smaller surface area combined with the flex in these fins makes them much more sensitive in the water and allows the board to turn a lot easier with less effort, which can be useful as longboards aren’t the easiest boards to turn!

Your turns will be more drawn out the further back the tip of the fin is in relation to the base. If you want to make tighter turns on your board then we recommend choosing a more upright shaped fin.

All-Around / Rake Fins

As the name suggests, these fins are great all-rounders. They are popular as their versatility makes them a great choice if you want one go to fin for using in multiple boards and surfing in a variety of conditions.

These fins are wide at the base and they are typically less narrow at the tip than flex fins which makes them nice and stable whilst still offering performance and drive to your board.

These fins are great if you are starting out and aren’t quite sure what your surfing style is just yet. They will work in any longboard and will allow you to cruise, turn and will even give you enough hold on the wave to cross step or hang ten.

Pivot Fins

If cross stepping and nose riding is your style, you will probably want a pivot fin for your log. These fins are thicker than the flex and rake fins, as well as longer and wider with a rounded tip, which gives them an increased surface area. All of these factors result in a fin that sits further down in the water and has a strong hold in the wave. 

When cross stepping or hanging ten, it is important that you have a fin in your board that will keep it steady and stable as your weight moves up the board towards the nose. Pivot fins will give you a nice drawn-out ride, keeping the fin locked into the wave nicely when nose riding but still allow you to turn the board from the tail. 

D - Fins

If you are looking for max trim straight down the line then this is the fin for you. This unforgiving fin is a classic style that is normally found on old school heavy traditional logs. The larger the surface area, the longer it takes for water to move around the fin which makes it harder for the water to move it suddenly - this helps to provide control of the board and hold in the water needed for large, heavy longboards.

D - fins are not recommended if you want to nose ride as their short length means they don’t sit very low down in the water. This makes the board quite unstable as your weight transitions up the board, making them unsuitable for nose riding. 

This shape of fin is great if you just want to cruise down the line in an old school style.

Fin Construction

Now you have deciding what style and shape fins you need; you will notice that there are multiple different construction types on the market. Each construction type will offer something slightly different. Read on to learn more about fin construction and the benefits of each type.

Fibreglass Fins

Fibreglass fins are the most traditional types of construction you can expect to find. These fins are made out of layers of fibreglass cloth and resin. Glassed on fins are usually made this way attaching the fin to the board.

Many companies make fibreglass fins that are strong and light and are usually quite stiff which means they are great in large, powerful waves when you want a stable fin.

Performance Core / PC Fins

These high-performance fins are made from a lightweight honeycomb or hexagonal core which is then coated in fibreglass and coated with resin.

This construction makes it possible to make larger fins lighter. When in your board, these larger, lighter fins help increase, speed and drive down the line.

Carbon Fibre Fins

Carbon Fibre is super strong and lightweight compared to other materials. These fins provide increased strength whilst still remaining responsive and having a good amount of flex. Often Carbon Fibre is used in combination with the core constructions to create durable, lightweight, speed generating, high performance fins.

 

Soft Flex Fins

These fins, most commonly found on beginner foam surfboards are made using a flexible urethane material. They are softer and less likely to cause damage in an impact, making them perfect for beginners who are more likely to fall off their boards when learning.

We hope this guide was helpful and that you now know what fins you need for every surfboard in your quiver!

If you have any questions about anything in this blog or would like any advice on fins, we are always more than happy to help! You can email us at: info@boardshop.co.uk or give us a call on 01243 674250.