Anatomy of GEARBOX

The interactive image allows exploration of the features of the box.

There are a lot of details that make up the GEARBOX Fin System, we will briefly introduce all of them, as they pertain to the system, in this section. By diving into all of these details we hope to provide a better understanding of the system.


GEARBOX is a strong, light, simple, easy to install, and customizable fin box. Designed to meet all of the key requirements for a fin system, while keeping things simple. Extensive testing and thinking has gone into the design in order to strip the system down to the bare essentials.

The GEARBOX 2 fin system consists of six (6) different boxes. Five (5) side boxes, featuring different cant angles, and a dedicated center box. Load beam collar cover. Designed for placement underneath the glass during the lamination process.

side & center boxes

A unique patented load beam collar with cover, turns the entire top surface of the cover into a bonding surface. Truss openings in the load beam collar lighten the weight without sacrificing strength. Outline shape of the beam improves roll strength of the system once installed. Features a wide mid-section providing largest possible footprint, without impeding close to rail installation.

The design of the collar does not restrict the cover material to any one material, anything providing a good bonding surface is fine. For example, in a balsa wood board the cover could be balsa so that the box blends in with the surrounding wood. The cover enables the application of various overlays, for example, carbon fiber, fiberglass, etc. Facilitating customization of the box appearance. Allowing the boxes to blend in with the rest of the surfboard!

Side box covers feature a recessed cant angle number centered at the outboard edge. This number indicates the cant angle of the associated box. Supported cant angles - 0º, 2º, 4º, 6º, and 8º. The cant angle is also marked in the slot, as well as on the bottom outside of the box. Making it easier to identify the cant angle.

The outer flange of the collar provides an aesthetic detail by forming a thin pin line around the perimeter of the cover.

Adjustment of 5mm (3/16") forward and backwards provided by the fin slot. Allows fin placement to be fine tuned. Designed to be compatible with all dual tab fins on the market. Each box ships with a card containing 3 pieces of die cut masking tape. These are used to cover the slot and screws during installation. Side boxes ship on trays containing 10 boxes, die cut masking tape, and 2 hex keys. Center boxes ship in packs containing 5 boxes.

box dimensions
load beam collar

A unique patented characteristic of the GEARBOX 2 design, is the load beam collar. Location of the cup shaped beam is below the upper surface of the box. A high density material placed within the load beam, increases the bonding area for the bottom laminate. This is called a cover.

Selection of cover material is based on good resin adhesion characteristics. Installation bonds the entire cover into the collar. Turning the load beam collar into a strong structural entity that is efficient at load dissipation. The design of the collar results in a cover that has the greatest amount of exposed surface area possible. Allowing for a superior bond with the bottom laminate of the board.

slot dam

A dam is a requirement for an under the glass system. It serves to provide a ramp over which the bottom laminate can be draped, allowing the dam to be exposed when the board is sanded. It also allows the grub screws to be protected during the laminating process.

Die cut masking tape is provided that fits the top of the dam to cover the slot and screws during lamination. The dam has high enough clearance above the bottom lamination to allow it to be sanded down to expose the slot and screws.

fin slot

The fin slot provides the housing for the base of the fin, and is designed to provide a snug fit for the base. The GEARBOX slot also provides an 5mm (3/16”) of adjustment for the fin, allowing the fin position to be tweaked!

The slot supports both GEARBOX and DUAL TAB bases.

fin slot

GEARBOX features a bridge at the center of the fin slot, on the bottom. This bridge serves to tie the two sides of the slot together for additional strength. Tying the sides together in this manner means the slot is less likely to spread apart under the loads applied to the base of the fin.

GEARBOX fin bases have a corresponding semi-circular notched cutout to fit over the bridge. Dual tab bases fit either side of the bridge.

grub screws

GEARBOX utilizes two grub screws to lock the fin into the slot. The screws are tightened down into a notch in the fin base that pushes the fin down, locking it into the slot.

For side boxes the two screws are placed on the stringer side of the box. While the the center box the screws are on opposing sides of the box.

fin base

The GEARBOX fin bases is a full length base in order to provide the strongest support in the slot. This minimizes the amount of flex in the base of the fin allowing it to flex as designed.

The base features vee notches onto which the grub screws land allowing for a compression fit into the box. These notches are designed to support adjustment of the fin position within the slot. The notch also minimizes the risk of the fin falling out of the box should the screws loosen.


A unique aspect of the GEARBOX system is the load beam collar and it’s associated cover. The load beam cover is a separate part from the box itself making it easier to optimize for bonding and appearance.

The cover provides the greatest possible bonding surface for the bottom laminate. Allowing for a stronger installation. The cover extends down through the trussing of the load beam, providing a better bond to the underlying foam shelf. Sandwiches the web of the load beam, locking it in place!

side & center covers

Hex covers are a new addition to the GEARBOX system, initially they can optionally be ordered in place of the standard covers. A hexagonal scoring pattern has been added to the upper surface of the cover. In addition, to the normal excellent bonding properties of the cover material, the scoring adds an improved mechanical bond! Hex covers will become the standard cover over the coming months.

The load beam cover provides the greatest possible bonding surface for the bottom laminate. Allowing for a stronger installation. The cover extends down through the trussing of the load beam, providing a better bond to the underlying foam shelf. Sandwiches the web of the load beam, locking it in place!

Because the cover is a separate part, from the box, its material can be optimized to provide the best possible bonding characteristics. All covers come pre-installed in a box, with a sanded upper surface! Loose covers can be purchased for customization purposes.

Besides the structural role that the cover plays within the load beam, it also has an aesthetic aspect. The large surface area, can be covered in different overlays to enhance the appearance of the installed box. Customization options are available for the cover. For example, the use of balsa veneer in a balsa wood board would compliment the appearance. This decorative covering is applied to the upper surface of the cover, can provide a wide range of other design options. These coverings can range from carbon fiber to wood veneers, or printed fabrics.

Installation strength is further improved through the extensive trussing in the load beam web. The cover extends through these truss openings, creating a bond between the cover and the surfboard foam.

Cover material selection is driven by bonding properties of the material to surfboard resin systems. Examples include high density foams, carbon fiber, wood veneer, fiberglass, or other structural materials. Provides greater creative flexibility with the box installation.

The standard covers feature a small recessed number at the outside edge, opposite the screws. This number provides an indication of the cant angle of the box. Because of its location it is visible after the box has been installed making cant identification easier when there are fins installed in the board. There are cant angle numbers for each of the available angles - 0º, 2º, 4º, 6º, and 8º. The center covers have no indicator!

color side covers
color covers

Optional color covers are available in seven different colors - BLACK, GRAY, YELLOW, MANGO, RED, BLUE, GREEN,and PURPLE! All these colors are also available for the center covers.

All color covers are HEX covers only! All of these colors are made from Expanded ABS.

NOTE: colors shown might not exactly match the finished product!

cant indicator

To simplify cant identification on finished surfboards, the cover features a recessed number on the outboard edge that indicates the cant angle. This serves as a permanent indicator that is visible when there is a fin installed.

Cover Cant Angle Range

The supported cant angles are - 0º, 2º, 4º, 6º, and 8º. Cant indicators are not present on color or custom covers. There are no indicators present on the center covers.

custom covers

One of the unique aspects of the GEARBOX system is the use of a cover in the load beam collar. Not only does this cover facilitate better bonding with the laminating system, it also provides a unique customization opportunity.

Covers can be optimized by overlaying the top surface with a wide variety of materials ranging from wood veneers to various exotic composite materials!

There a re two distinct types of customization that can be performed on the covers, depending on which cover is being used as the base.


Hex covers are used for most of the customization options. There are two different types of customization - inlay and overlay. The inlay process involves sanding down the cover by the thickness of the inlay material that will be added to the top surface. Normally, the inlay materials are selected based on the resin absorption of bonding characteristics. The most common materials are wood veneers as these are relatively thin a easy to apply to the surface, while still providing excellent resin absorption. Customization is most commonly built on top of an existing cover in order to better control the fit into the collar. But it is possible to completely replace the cover with one made of a different material.For the overlay process a material is added to the top of the cover that extends over the flange lip as well completely hiding the edges of the box. We provide a simple guide to cover customization here.


Hex covers can also be customized by filling the grooves in the covers with different color resin, allowing the hex pattern to be accentuated. This is easily performed with a syringe, then once the resin has cured the covers top surface is sanded down. A guide is close to being ready that will provided instructions on how to perform the customization and will be found here.


Routing System

GEARBOX 2 has a complete routing system that supports two distinct installation options - STANDARD and 1ROUT. The STANDARD system is the primary system used for general installation. The 1ROUT system is geared towards installs in low density EPS foams. Both of the routing systems will be explained in greater detail in this section.


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.


+61 417 243 592


+1 808 639 5303

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