When I got the Infinity Quad I was trying to figure out what fin setup to use and what the difference would be. Here’s a Q&A with Steve Boehne from Infinity Surf with those answers.
The Quad Cluster has five fin boxes. What are the suggested fin setups and what difference will it make in performance?
The first rule is that each guy is different and he should experiment with fin configurations to find his own preference. We normally don’t put 5 boxes in the quads, but we did this one so you could have fun experimenting. Traditionally, a quad has the two largest fins in the front boxes and the smaller twin fins in the rear boxes. You may notice that the front boxes are installed near the rail and towed in and the rear boxes are closer and parallel to the stringer. We found that unlike a short board, which is ok to be kind of “squirrelly”, an SUP feels better with positive directional control. This is achieved by moving the rear fins in and parallel. The center fin is not usually used unless you are riding it as a tri fin thruster or if you really want to make it positive.
Would you ever ride this with a 2-fin setup? If so, why?
As a twin fin, the tail is very “drifty”. It holds ok in a turn, but slides around a lot on the straight-aways. There are probably guys who would like that slidy feel.
What’s the difference in performance when riding the board as a 3-fin thruster vs. a quad setup?
The quad will give you more projection out of a bottom turn. With only three fins, the board will not have as much fin surface to push against. In addition, since the rear fin of a thruster is way back on the tail, it is a little bit stiffer. A quad is really just a thruster with two rear fins. The reason that a quad turns better is because the rear fins are moved about 4” closer to the front fins than a true thruster. The further the spread between the front fins and the rear fin(s) the stiffer any board will be. We learned this over twenty years ago with our innovative Cluster fin design.
Which fin setup (quad or 3-fin thruster) is better in larger waves?
Large waves may be the time to use the center 5-fin option. This will stabilize and stiffen the board to give you control, just as the increased speed is making the board feel looser and out of control.
I want the board to turn like as close to a shortboard as possible. What fin setup should I use and where do I place the fins?
You should experiment to see what you like, for example, try putting the smaller twin in the front boxes and put the larger twins in the rear boxes. I would say that the thruster or 5 fin option will be the stiffest.
Actually, the board shape has just as much to do with it. Since a stand up paddleboard must be so wide to stand on, it is really hard to bring up onto the rail in a bottom turn. My Quad shape has an exceptional amount of “V” bottom. This V helps bring the board up onto the rail and really speeds up the turn.
How does moving the front, middle and back fins forward or back affect the performance and turning?
Switching the position of the large and small quad fins will slow down the turn a little, but make the board feel more predictable or less radical.
Why did you choose to use the Lokbox fin boxes?
The EPS foam we use is softer than urethane foam. A twin fin box will fail when there is an impact from the side. The box is actually pushed down in to the board as the foam compresses. We can install the Lok boxes into the board stronger than other boxes because their edges are rounded underneath which allows the glass to flow under them better. We glass the bottom of the board, then press the glass down into the routed fin box hole and then lay the Lokbox on top of the glass and put another layer over the top. This installation method drives laminators crazy, but it is by far the strongest way to go. We also wrap the glass down into the routed box cavity on our center boxes to repel side impacts. One more thing, if you hit the reef straight on, the Lokbox fins are held in by a “fusible” tab that will bend and let the fin fall out before the box is ripped out.
The nose is fairly wide. Is this board a nose rider?
The wide nose is for more stability while paddling, why constantly struggle with your balance? But you know, these really short SUP’s are much easier to nose ride then the longer ones because you don’t have to walk so far to nose ride.
Would this board be considered a good noserider?
It will nose ride well because of the wide nose and short length. With over 18” of fin(s) on the tail, it will hold in just fine.
What makes this board stand out over the other models you make and over other models in the market?
There are many creative shapers making wonderful boards, we are all striving to make our product the best and to keep a smile on every surfers face. Each of my models usually optimizes a different goal; nose riding, turning, easy paddling or speed. The quad model has a wide nose and tail template for good stability. The bottom has a lot of “V” to help get it up on the rail. This design makes riding a super short SUP very easy.
Do you glass under and over all the fin boxes in all sup boards? Why?
Covered that earlier, but we have always done that with Lokbox. Now with the softer EPS foam I think it is absolutely essential.