Surfboard Fin Details

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Fins are the bits that poke out from underneath the surfboard. They all have a similar curved appearance but come in a variety of shapes, sizes and flexibility depending on a surfers needs. There are two general types of fins, glassed on and removable, The only difference is that you can take your removable fins out when you like - all other performance properties are based on their measurements,. The purpose of the fin is to help steer your surfboard. Let's take a look at the Fin in detail.

Fin Measurements

Depth
The Depth is the measurement from the tip of the fin to the base of the surfboard (not the end of the fin plug) or how far the fin goes into the water. The Fin Depth effects how the board 'holds' in turns. The deeper the fin the better the control in the turn.
Remember: Depth = how far fin sticks in water!

Base Length
The Fin Base Length is measured at the widest point of the fin, where the fin meets the bottom of the board. The Base Length determines its speed and drive. The longer the base length the more speed and the greater the drive the fin contributes. Want to go fast? think long base!
Remember: Base Length = Length of Base of Fin!

Fin Plug (Removable Fins Only)
The Fin Plug slots into the Fin Box on the base of the surfboard. The fin can then be secured in place for surfing. Fin Plugs com in different shapes and sizes depending on the type of removable fin system. Below is a close up image of an FCS™ Fin System showing the Fin Plug, Fin Box and Fin Screw (to tighten the Fin into place once it has been slotted into the Fin box).
Remember: Fin Plug = Plug to attach removable Fin!

Removable Fin and Fin Box

Glassed On Fin

Rake
Nothing to do with gardening I'm afraid. Rake, also know as Sweep, can be thought of as the amount of the fin outline that is curved backwards. Essentially it is the angle created between the back of the Fin Base and the offset of the tip of the fin. The Rake affects the turning ability of the board. The smaller the Rake angle (i.e. the greater the offset) the better the drive but less maneuverable the board will be. The larger the Rake angle (i.e. the less the offset) the tighter the board will be able to turn.
Remember: Rake = Fin Offset (not Gardening Implement)

Next we will go on and talk about Flex, Replacement Fins and Fin Positioning. >> More Fin Information
Don't forget to find out further information on the Underside of a Surfboard including the different bottom contours.