A Guide to FIN SETUP and TERMINOLOGY
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.
Terminology
- fin triangle or cluster
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This is the grouping of the fins, whether a thruster, quad or 2+1; it refers to the entire fin layout.
- fin setup
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This is the position of the entire fin cluster as a unit, either all forward, all back, spread apart, grouped, etc.
- cant
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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.
- toe-in
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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
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This is the position of the fin in the box forward or backward along the length of the board.
- spread fin cluster
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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
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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.
- thruster setup
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A thruster setup consists of side fins and a center fin, with the most common setup featuring fins all the same height.
- quad setup
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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
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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.
- twinzer setup
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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
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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
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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
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TRAIT
longer turning arc, more common on longer boards or guns
CONDITIONS
larger faster waves, situations where a gun would more likely be used.
- tight fin cluster
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TRAIT
shorter turning arc, the common setup for smaller thrusters
CONDITIONS
wide range, depending on skill and the shape of the board.
- fin cluster forward
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TRAIT
looser, shortest arc, less hold
CONDITIONS
pivotal surfing on small to medium waves.
- fin cluster normal
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TRAIT
loose with control, typically the position designed by the shaper
CONDITIONS
versatile, wide range of conditions.
- fin cluster back
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TRAIT
more control, more projection, bigger tube/pocket waves
CONDITIONS
once again typical for situations for a gun.
- more fin cant
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TRAIT
looser with less drive, requires more turning to generate speed
CONDITIONS
small to medium surf.
- less fin cant
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TRAIT
stiffer with more drive, bigger, faster hollow surf
CONDITIONS
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.
ILLUSTRATED TERMS
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.
