Fin boxes have been used on surfboards for years and are typically found on longboards, SUP’s and retro style boards. Fin boxes allow a single fin to be moved forward and back in the box, which essentially changes the way the board feels.

Traditional single fins use a screw and plate to secure the fin into the box.

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Inserting the Plate, Screw and Fin

You’ll notice a small square opening in the centre of the fin box, this allows the plate and fin to entre the box and lock into the horizontal channel.

First slide the plate into the opening and push it toward the front of the box, next slide the back of the fin into the box ensuring the pin is locked into the channel.

Next push the front of the fin down, but make sure you line up the hole at the front of the fin with the plate, and then, insert the screw.

How to insert a fin that has a tight fit

If the fin is really tight you can sand the base slightly with fine sandpaper, or apply a small amount to olive oil to make it slide in easier.

How to select the correct longboard fin placement

Before tightening, move the fin to the desired position. Moving it forward will allow the board to turn easier and in a tighter radius, moving it back will lengthen the turning arc and give more control, especially in bigger waves, this is also the preferred position for nose riding.

Next push the front of the fin down, but make sure you line up the hole at the front of the fin with the plate, and then, insert the screw.

To remove the centre fin from your longboard or SUP

To remove the fin un-tighten the screw until the front of the fin can be lifted from the box, then slide the back of the fin to the middle of the box until the pin exits freely.