Fin placement can have a dramatic effect on the performance of a surfboard. This primer is geared towards providing our customers with a better understanding of how the forward and backward adjustment of the fin setup, and placement of the fins, can affect the performance.
At best this is more art than science, but 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 the overall performance of a board.
This primer will use some terminology that is best explained up front so that we are all speaking the same language.
When experimenting with your fin placement always start with the fins centered in the GEARBOX, then start making adjustments from there, typically this is the position the fins will be in when on the shaper’s marks. Although the range of adjustment in a GEARBOX is limited even this small amount can make a difference. Because the system does not support cant adjustment it is important to consider the cant selection before the board is constructed.
It is also worth mentioning that while fin adjustment can have a dramatic impact on performance, the templates of the selected fins are even more critical. Selecting the wrong fin shape for the intend use can easily override any changes that are made in the adjustment of the setup.
So it is worth paying close attention to the selection of the fin templates and their intend use!
Above 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.
Our system was designed to provide some adjustability, making it easier to experiment hands on with fin adjustment.
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 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.
Another critical measurement is the toe-in of the boxes 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.
We have two primary office locations for GEARBOX and Hanalei Fins, Australia and the USA. Contact info is provided below but the preferred contact method is through the CONTACT form on this site.