This primer will use some terminology that is best explained up front so that we are all speaking the same language.
|fin triangle or CLUSTER||this is the grouping of the fins, whether it be a thruster, quad, or 2+1, it refers to the entire fin layout.|
|fin setup||this is position of the entire fin cluster as a unit, either all forward all back, spread apart, grouped together, etc.|
|cant||also referred to as fin angle, is the amount by which the side fins are leaning out from the centerline of the surfboard, bottom up.|
|toe-in||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 backwards 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, side fins all the way forward, center fin all the way back, this generally makes the board stiffer. For quads the fins are spread as far apparent as the box adjustment will allow.|
|tight fin CLUSTER||the opposite of the spread fin cluster, typically side fins all the way 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 will allow, front fins all the way back, back fins all the way forward.|
|THRUSTER setup||a thruster setup consists of a set of side fins and a center fin, with the most common setup featuring fins that are all the same height.|
|QUAD setup||a quad setup consists of a 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 the smaller set of 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||a twinzer setup consists of a two sets of side fins, with a small set of 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. The canard fins typically have additional cant built into the base in order to have more cant than the boxes typically provide.|
|5FIN setup||a 5FIN setup is simply a quad setup with the addition of a center box, 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 a set 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.|
|SINGLE fin setup||single fins are either setup in a regular longboard center box, or glassed on to the bottom of the board. One fin setup on the board centerline.|
Below is just a small sampling of the more obvious 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.
Obviously, the position and cant of the fins are very important and greatly affect the performance of a surfboard. The smallest change can sometimes have a dramatic effect on 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 is applicable 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. Placement of the center fin is going to be by far the more controlling aspect of the performance of a 2+1 setup.
Of course there are other factors that can affect fin setup, the size and shape of the fin, even the foiling of the fin. Whether all of the fins in the cluster are the same size, or not. 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.
|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 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 terminology.
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, showing the cant angles of the fins in the cluster. When talking about fins this is the most common view used to refer to the left and right fins.
Shows how the cant angle is measured. With the GEARBOX fin system the cant angle is built into the box. The correct cant angle needs to be selected before installation.
Toe-in of the boxes, is another critical value, shown in this drawing.
This is the distance that the boxes are pointed in towards the stringer, from the box centerline. In quad setups this can vary from the front to the back fins.
A spread fin cluster is where the fins are spread as far apart from each other as possible. For a thruster this means the side fins are as far forward as possible and the center fin as far back as possible. For quads the front fins are as far forward as possible, and the back fins as far back as possible.
A tight fin cluster is where the fins are pushed as close together as possible. For a thruster this means 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 as far forward as possible.
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