Take your surfing to the next level with the GEARBOX Fin System!



A Collection of Useful Resources

This page contains a collection of resources, such as fin layout guides for different types of boards and fin setups. These guides can be freely downloaded to serve as a hardcopy reference.

We start with a Fin Setup Primer, which should help build a better understanding of fin layout and terminology. A downloadable version is also provided.

The layout guides provide information on fins' positioning for various fin setups. They are not specific to any given board length, as they are only intended to serve as a starting point. It is left to the builder to determine their preferred layout.

Various guides also detail the GEARBOX system fin base and layout options. All are available as downloadable PDF files.

Finally, a new TIPS & TRICKS section provides ideas for improving an installation's strength or quality or gaining a better understanding of the process. As new ideas arise, they will be added to this section.

Most of the sections on this page are initially collapsed to reduce scrolling. Then, click on the associated section icon or image to expand the content.



At best, this is more art than science, but well worth experimenting with!

The beauty of an adjustable fin system is that you can go out and experiment for yourself to verify what effect a change in fin placement can have on a board's overall performance.

This primer will use some terminology best explained upfront so that we all speak the same language.



fin triangle or cluster

This is the grouping of the fins, whether a thruster, quad or 2+1; it refers to the entire fin layout.

fin setup

This is the position of the entire fin cluster as a unit, either all forward, all back, spread apart, grouped, etc.


Also referred to as fin angle, it is the amount by which the side fins are leaning out from the centerline of the surfboard, bottom up.


This is the amount that the front of the fin boxes are pointed in (toed in) from the centerline of the box towards the stringer.

fore ’n’ aft

This is the position of the fin in the box forward or backward along the length of the board.

spread fin CLUSTER

This is where all the fins in the cluster are spread as far apart as possible, and side fins all the way forward and center fin back. This generally makes the board stiffer. The fins are spread as far apart as the box adjustment will allow for quads.

tight fin CLUSTER

The opposite of the spread fin cluster, typically side fins back and center fin all the way forward, makes the board looser and more pivotal. For quads, the fins are pushed as close together as the box adjustments allow, with front fins back and back fins all the way forward.


A thruster setup consists of side fins and a center fin, with the most common setup featuring fins all the same height.

QUAD setup

A quad setup consists of two sets of side fins, with the most common setup featuring a larger set of fins in front of a smaller set. The placement of these two sets relative to each other can vary widely, but our preference is for them to be close together.

reverse QUAD setup

A reverse quad setup consists of two sets of side fins, with smaller fins in front of a larger set. The placement of these two sets relative to each other can vary widely, but our preference is for them to be close together. This is a term we coined to describe this setup arrangement.


A twinzer setup consists of two sets of side fins, with small canard-style fins in front of a much larger set. The placement of these two sets relative to each other is typically very tight to allow the canard fin to serve as a transition fin to the larger fin. In addition, the canard fins typically have additional cant built into the base to have more cant than the boxes usually provide.

5FIN setup

A 5FIN setup is simply a quad setup with the addition of a center box, and this allows the board to be ridden as either a quad or a thruster or with all five fins.

2PLUS1 setup

A 2+1 setup consists of side fins and a much larger center fin, most commonly placed in a regular longboard center box. The side fins are commonly very small in relationship to the size of the center fin, but the heights can vary.

Fin Setup Traits


spread fin CLUSTER

longer turning arc, more common on longer boards or guns

larger faster waves, situations where a gun would more likely be used.

tight fin CLUSTER

shorter turning arc, the common setup for smaller thrusters

wide range, depending on skill and the shape of the board.

fin CLUSTER forward

looser, shortest arc, less hold

pivotal surfing on small to medium waves.

fin CLUSTER normal

loose with control, typically the position designed by the shaper

versatile wide range of conditions.

fin CLUSTER back

more control, more projection, bigger tube/pocket waves

once again typical for situations for a gun.

more fin cant

looser with less drive, requires more turning to generate speed

small to medium surf.

less fin cant

stiffer with more drive, bigger, faster hollow surf

commonly used in twin fins, guns or tow-in boards.

The above is just a tiny sampling of the more apparent combinations. There are many more in between or with subtle variations. The intent has been to provide a little insight into the more general characteristics of fin placement.

The position and cant of the fins are critical and significantly affect the performance of a surfboard. The slightest change can sometimes dramatically affect the board, but it is not a magic bullet. Sometimes, the opposite effect can occur. Fin setup is just one piece in a complex dynamic system of shapes and curves that make up a surfboard.

Each board is different, as is each surfer so any changes could have different results depending on the board and the surfer!

The information provided above applies to a 2+1 fin setup, except, in that type of setup, the size of the center fin has a more heavily weighted effect on the cluster. The smaller the center fin, the more it will perform like a thruster. Therefore, the placement of the center fin will be the more controlling aspect of the performance of a 2+1 setup.

Of course, other factors can affect fin setup, the size and shape of the fin, and even the foiling of the fin, whether all of the fins in the cluster are the same size. However, we believe the beauty of an adjustable system is that it allows the surfer to experiment for themselves to determine what works for them and to help them learn the significance of being able to adjust the fin setup on a surfboard.

Our system was designed to provide some adjustability, making experimenting hands-on with fin adjustment easier.


The renderings in this section show illustrations for some of the terms used in the fin setup discussion. Hopefully, these will provide a visual guide to some of the terminologies.


Shows what is referred to as a fin cluster, which is the combination of all of the fins in the layout.


Another view of the fin cluster from the rear of the board shows the cant angles of the fins in the cluster. This is the most common view used to refer to the left and right fins when talking about fins.


It shows how the cant angle is measured. The cant angle is built into the box with the GEARBOX fin system. The correct cant angle needs to be selected before installation.


The toe-in of the boxes is another critical value, shown in this drawing. This is the distance the boxes are pointed towards the stringer from the box centerline. This can vary from the front to the back fins in quad setups.


A spread fin cluster is where the fins are spread as far apart as possible. For a thruster, the side fins are as far forward as possible, and the center fin is as far back as possible. For quads, the front fins are as far forward as possible, and the back fins are as far back as possible.


A tight fin cluster is where the fins are pushed as close together as possible. For a thruster, the side fins are as far back as possible and the center fin as far forward as possible. For quads, the front fins are as far back as possible, and the back fins are as far forward as possible.













2PLUS1 Layout











While the STANDARD and 1ROUT installs work perfectly there are still tricks, or slightly different approaches, that can be used to enhance an install.

We will share some of these thoughts here as they could be useful, either as an adjunct to the normal install or a revised approach.

Bear in mind, as with any install methodology, it really helps to run a few test installs before adopting any changes. This will provide a better feel for the process and help boost confidence that the right choice was made.

We will also go into more detail regarding the setting of the router bit depth to deal with deep concaves.

As always if there are any questions CONTACT us, we are here to help.


Section through center of 4ΒΊ GEARBOX and foam cavity

The illustration above shows how the box would sit in the cavity when performing a typical install using the STANDARD router depth setting. Optimally, it should be slightly below the bottom of the board. More on this later!

The motive for pre-gluing the boxes into the cavity is twofold. First, it is a lot less stressful and gives you the time to get everything set up perfectly (for those that prefer to have a fin in the box to check cant angle, it makes that more accessible). Second, it means a coat of resin can be applied over the top of the cover filling in the hex grooves and creating small curved ramps against the dam and outer edge of the cavity. See the detailed image below.

To pre-glue the boxes, the routed cavity is covered with resin, as is the underside of the box. Then insert the box into the cavity and allow any excess resin to squeeze out. Next, using a brush, spread the resin over the cover and the lower edge of the dam. Due to the nature of the resin, it will create a small fillet at the dam and the outer edge of the cavity. This makes it much easier for the cloth to drape over the box. This is one of the main reasons the box should sit slightly below the lip of the cavity.

Section showing resin coating over cover and fillets at dam and cavity edge

Section showing resin coating over cover and fillets at dam and cavity edge

Section showing resin coating over cover and fillets at dam and cavity edge

Section showing hot coat applied to board and box

Section showing box and dam sanded down after hot-coating

The illustrations above show step-by-step how this works.

Another reason for setting the box slightly below the cavity edge: This technique allows the bottom lamination and reinforcement layers to drape down over the box cover more easily.

This is important because if the box were flush with the bottom of the board, there would be a greater risk of sanding through the lamination or, at the very least, grinding away the second reinforcement layer. By lowering the box, the cloth ends up slightly below the bottom of the board, making it much harder to sand through the layers.

Once the boxes have been glued in, lamination can proceed, or if it is a post-lam install, the reinforcement layers can be applied. The gelled resin used during the gluing process makes pressing the cloth tight against the box very easy as the resin will still be tacking. This will help hold the fabric in place while laminating.

It is essential always to place the SECOND reinforcement layer ON TOP of the bottom (or first) layer. The reason is that sanding through the bottom layer is less risky, which would be very easy at the edges of the reinforcement layer if it was underneath the primary layer.

With the dam's new shape, you will find that this process makes for a very clean install with little to no air around the base.

Look at the image below; you can see just how tight this process allows the glass to be around the dam after it has been sanded down. This makes for a much stronger install.

This photo shows just how tight the glass can be made to fit around the dam. This is a box sanded down before glossing, showing the two layers of glass.


Base jig setup on a deep concave

When performing an install in a board with deep double concaves, there is an extra precaution that needs to be taken to ensure the boxes install cleanly.

End view shows how the base jig spans the concave

When the base jig is placed on a deep concave it can bridge the concave, as shown in the illustration above. When this happens and the STANDARD router depth is utilized the box will not sit flush.

After routing the box would end up sitting slightly above the lip of the cavity

Normal rout would leave the box sitting above the lip of the cavity

For this reason the depth gauge provides a CONCAVE depth that sets the cavity deeper. The aim here is to get the box to sit slightly below the lowest part of the concave. In some cases the depth gauge might not provide enough depth due to the severity of the concave. Always do a test run to check that there is enough depth.

Box positioned slightly below the lowest lip of the cavity, by doing a deeper rout

Using the CONCAVE depth on the gauge the box should end up slightly below the lowest lip of the concave. As shown in the above illustration.

Final routed cavity

GEARBOX - An advanced removable surfboard fin system.


Primary office locations for GEARBOX - Australia and Hawai'i (USA). Contact info is provided here, but the preferred contact method is through the contact form on this site.

+61 2 4339 9580

+1 808 639 5303