Surfboard Fins

There are many kinds of surfboard fins and many types of surfboard fin systems available today. Most surfboards today come with the removable, as opposed to glassed-in, fins. They are not all cross compatible. Most have boxes that are specific to that brand.

• Depth - This is the fin's maximum height as measured from the bottom surface of the board. This ishow far the fin goes in the water. The board's hold increases with more depth but generally makes it harder to turn as well. 3-4 inch depth is standard on tri-fins and longboard single fins typically have a depth of nine inches.
  
  
• Template - The fins outline.
  
  
• Base - The length of the fin where it joins the surfboard. Increasing length adds forward drive, but makes it harder to turn. Shortboard tri-fins usually have a 3.5-4.5 inch base, longboard single fins are about 6 inches.
  
  
• Foil - The horizontal curve of the fin, measured from the front edge to trailing edge.
  
  
• Rake - The distance betweent thetrailing edge of the fin base and the fin tip. This is the swept back characteristic of the fin. Increasing rake increases traction.
  
  
• Tip - The top third of the fin. More tip means more hold.
  
  
• Flex - Stiff fins are faster but flexible fins are easier to turn.

Board performance is greatly affected by the fin setup, which is the number, size, and placement of fins:

• Single Fins - The way it all started. This setup is very common on modern longboards. Single fin shortboards have also become more common as an "alternative" board. The single fin is a large fin to provide the necessary hold. The placement of the fin is further towards the back than most fin setups to allow more control.
• Twin Fins - Very popular in the 70's, but still common among modern fishboards. Losing the center fin makes the board losser and easier to turn and increases speed by reducing friction.
• Thrusters - The vast majority of modern shortboards have this three fin setup. The fins are almost the same size. The two toe-in side fins provide the responsiveness while the center fin adds stability. This setups likes to be turned constantly to generate speed and is more challenging the most fin setups. This setup is also common on hybrid surfboards and funboards.
• Quads and Twinzers - These are both four fin setups the are most popular on fishboards. Twinzers have two signficantly smaller fins set foward. Quads have almost all the same size fins, but the forward fins are slightly larger than the rears. Both are known for having fast down the line speed with better hold than twin fins. They provide for a more "skatey" type surf style. These fins don't break loose like a thruster so the turns on these aren't as radical, but for many, including me, they feel more natural.
• 2+1 Fins - Large middle fin with two small side fins. Very popular on many longboards. The side fins add some responsiveness as compared to just the single fin.