Surfboard Fin Details
Fins are the bits that poke out from underneath the surfboard. The purpose of the fin is to help steer your surfboard. They all have a similar curved appearance but come in a variety of shapes, sizes, and types of flexibility depending on a surfer's needs. There are two general types of fins: glassed-on and removable. The only difference between the two is that you can take out your removable fins when you like; all other performance properties are based on their measurements. Let's take a look at the fin in detail.
The depth is the measurement from the tip of the fin to the base of the surfboard (not the end of the fin plug), and it is essentially how far the fin goes into the water. The fin depth effects how the board "holds" in turns. The deeper the fin goes, the better the control is in the turn.
Remember: depth = how far the fin goes into the water!
The fin's base length is measured at the widest point of the fin, where the fin meets the bottom of the board. The base length determines the board's speed and drive. Fins contribute more speed and greater drive with longer base lengths. Want to go fast? Think long base!
Remember: base length = how much speed and drive the fin provides!
Fin Plug (Removable Fins Only)
Fin plugs slot into the fin box on the base of the surfboard. The fin can then be secured in place for surfing. Fin plugs come 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. (The fin screw is used to tighten the fin into place once it has been slotted into the fin box.)
Remember: fin plug = the plug used to attach a removable fin!
Removable Fin and Fin Box
This has 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's 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 is (i.e. the greater the offset), the better the drive but less maneuverable the board will be. The larger the rake angle is (i.e. the less the offset), the tighter the board will be able to turn.
Remember: rake = fin offset, not gardening implement!