Stand up paddleboard fins are an essential part of your paddleboard rig. Without fins your board would start to turn radically with every stroke, making the whole paddling experience pointless. Fins allows you to move forward in a relatively straight line, or “track”. They prevent the tail of the board from slipping sideways as you put pressure on either side of the board as you go through your stroke. The design of the fin also affects speed, stability and how easily you can turn your board.
A fin can be broken down into the following sections:
▪ Base and Tip: The base is the top section of the fin, closest to the board when installed. It is usually the widest part of the fin and it helps to stabilize the board and affects tracking. The Tip is the other end of the fin that extends down into the water. The tip also affects tracking and speed.
▪ Trailing Edge: The trailing edge is the back of the fin and it also affects how easily, or not, a board turns and pivots. Trailing edges aid in releasing water to greater or lesser extent, which affects speed.
Fins can be set up in a number of ways, here are the most common ways that they are set up.
Large Single Fin: This is placed in a finbox and secured with a nut and screw. The finbox has a channel for the fin to slide back and forth. When the fin is pushed toward the tail, the board will track better, which is best for racing, touring or flatwater paddling. If you push the fin forward toward the nose, the board will turn easier, which is better for surfing or whitewater.
3-Fin Setup: Also called a thruster, this setup was originally designed for surfing but also works with tracking on flatwater. If you remove the center fin of a 3-fin setup, the 2 side fins, also called “side bites,” will still work for tracking on flatwater or in surfing.
Race Fins: These come in a variety of styles. Some have a rigid shape versus a traditional surfboard flex fin. These straighter, stiffer fins are best for downwind runs because they help longer boards (up to 14’) track easier in large wind waves or rolling swell. Downside: If a rigid fin hits a rock, you will most likely face-plant. Other fins are more flexible and will give when in contact with a rock, log or the beach. While not as performance-oriented, they will bounce off obstructions so you can continue paddling.
Inflatable SUP Fins: These feature either flexible rubber fins attached to the board or detachable semi-rigid fins that can be removed.
Fins are usually made out of plastic, fiberglass, or at the top of the spectrum carbon fiber.
If you are looking to get more performance out of your board, then experimenting with different fins is good place to start. You can have several fins that you use for different applications, or you can find one that does a couple of things well, but may not be the best for any one situation. Either way, there are plenty of options to choose from and it will never hurt to try something new.