How to Choose the Right Fin Setup for the Right Surfing Conditions

The surf is on, you’re grabbing your favorite SEPTEMBER swimsuit, the mid-length waits for you in the trunk of the car but should I ride it as a single fin? Maybe a two plus one? Or what will it feel like as a quad? Does a mid-length twin fin sound crazy?

Too many questions. Not enough answers.

The answer might be a little clearer than we first thought.

First, let’s check the conditions and put them into four categories:

• Small (up to head high)
• Big (overhead +)
• Fast peeling
• Slow peeling

And our fin options:

• Single fin
  
• Twin fin
  
• Two plus one
  
• Thruster / Tri-fin
  
• Quad fin
  

Most of us regardless of our level can sit on the beach and roughly determine where the conditions fit into these parameters, and the boundaries between them can be relatively flexible. A big or fast wave for you might not be big or fast for someone with more experience; so be honest with yourself and take it personally.

So let’s relate fin selection to those categories.

Small or soft waves are low on the potential energy from Gravity. If we’re not as high up or the wave slope isn’t so steep, then we won’t have much of a hill to drop down and gain speed. This means we need to make the board as efficient as possible, so it can still function in low energy waves. Allowing water to flow underneath the board with as little disruption and turbulence as possible is our ticket to this. So less fin = more laminar and clean water flow producing more lift to reduce drag, and more forward thrust. In big or steep waves where we have a good hill to drop down, then we’re not so concerned about finding speed, but instead getting down the line and past fast-breaking sections might be the challenge.

 

Center fins and side fins have slightly different jobs; the center fin provides straight-line stability and stops the board from slipping and sliding side to side (like the keel of a boat), it also provides a rigid point to push on so we can direct and point the nose where we want to whilst maneuvering. Without it, you can imagine the tail sliding instead of directing.

The side fins also stop the board from slipping but it’s not their main function. You might have noticed side fins aren’t symmetrical, they have a flat side and a curved side. The design is deliberately like an airplane wing made to generate lift. In our case, that lift is directed towards the wave face; keeping you locked and gripped into the wave face aiding in generating speed down the line.

Single fins prevent slipping at the rear of the board during turns, allowing the rider to push off the tail and direct the nose in a predictable pivoting way. The center fin creates a bit of drag, and so we often need to compensate by having a larger board or a bigger steeper wave that will provide the speed. That's why longboards/ logs work well as single fins in small surf, but mid-length or smaller boards with single fins need more of a meaty wave.

 

 

 

In brief, twin-fins are fast as they allow water to flow underneath the center of the board with low turbulence (no center fin disrupting the flow). The clean water flows backward producing more thrust forwards. And since the twin fin fins are often fairly large, they produce a lot of lift towards the wave face, so surfing down the line they can lock the board into the wave face and generate strong speed and grip. Without the center fin though they are a little looser and slippy when we lean on the back foot to maneuver, as the missing center won’t hold and direct the nose. What that means is twin fins are well suited to small or soft waves where generating speed is the priority but expect a little less predictability when maneuvering.

The two-plus has the directional stability of a single fin, with a small portion of rail engagement from the side fins. Sometimes the overall size of the three fins is a bit smaller than a normal single fin, or normal side fins, and that’s so the overall drag created is less. Look for a bigger wave or faster wave for this setup to work best as we need to compensate for the drag.

 

The truster or tri-fin is a ‘best of both worlds’ sort of thing where the center fin gives directional stability without slipping, and the side fins generate speed and grip from the wave face. So when the waves are bigger or faster they give you more security and predictability to work with. That's basically why they’re almost exclusively used in contests as the riders are often on good waves trying to push the board to its maximum. If the conditions are going to push YOU to the maximum (i.e it’s big or fast) then use the thruster.

Quad fins as you probably can now predict give a super-strong rail engagement into the wave face since it’s all sideways lift into the wave. So on big waves or super fast waves (even small & fast) like tubing waves where you need to get down the line quickly, the quad can be the ticket to making it down the line and past breaking sections.

So, when you’re choosing between the Lola One Piece or the Rita and Lolita bikini top and bottoms why not also choose your fins. Throw all of them in the trunk and decide at the beach; just don’t forget the fin key.