The bottom part of the fin which attach to the board with allen screws. With FCS the allen screws usually attaches from the side (there are newer FCS technology which you can simply pop the fins in without screws) and with Futures there attached on the bottom of the base. The longer and wider the base, the more smooth in the turn transition and the ability to follow through the turn smoothly. With a smaller slimmer and shorter base, there is more ability for sharper turns. Below you’ll see the differences between FCS and Future fins.
The Fin Rake is refered to as the angle/arc of the fin. Fins with more angle and less sharp stance are generally used to for those large waves and smooth transitions in riding the longer waves. Fins with more of sharp angle and more fin in the water will provide quicker turns and movements in smaller sections.
The movement of the water through the fin. I found a couple of different shapes listed below.
• Flat Foil – generally allows riders to pivot quickly through turns while giving them really good overall control. This is the most common foil pattern.
• Inside Foil – a more advance design built to reduce fin drag riders can manage and increase their speed in heavy sections.
• 80/20 Foil – This center fin is built for increase speed and smooth transitions in various conditions.
• 50/50 Foil – The most common center fin and provides built evenly to allow water to pass through evenly. Good hold and control.