Tips for Choosing River SUP Fins
“What fins are you running today?”
This is a common question us whitewater stand up paddlers often ask each other before getting on the river. Some of us geek out on this topic more than others. But your fin choice can have a huge effect on your paddling experience. The anxiety around making the best choice is somewhat warranted. Fins are important! So, let’s get you well versed on the subject so next time someone asks you, “What fins are you running today?”
You can answer with something like, “Well, it’s more shallow than it is deep but can also be pushy in spots so I’m going to go with a 4.5″ gummy and 2″ side bites.”
Instead of, “I don’t know, what are you running today?”
What is a fin?
A fin is a hydrofoil that is attached to the underside of the tail of a board that helps with directional stability. Meaning, the fin is going to help your board stay pointed in the direction you want to go, as well as, offering up some resistance against lateral waves. Running with no fins might make it easy for your board to turn but when its time to go straight you’ll find it very challenging to stay on course. Unless you’re paddling extremely shallow rivers you’ll probably always be running some kind of fin set-up.
Types of fins and when to use them…
Fins come in all shapes and sizes. Choosing which fins to buy can be overwhelming, fortunately when it comes to paddling rivers it is pretty straight forward and simple. It’s when you get into flat water racing and surfing that fin selection and technology becomes understandably much more complicated.
We use to make and carry 6″ center fins, but we found that 4.5″ in almost every whitewater situation is enough center fin if you are able to include side fins in your configuration. Whitewater stand up paddle boards tend to have more volume and width (to make it more stable in rapids) than non-whitewater boards. Having a lot of fin can make it more challenging to maneuver the board and set-up your angles. You’ll notice we call this fin a soft flex fin. That’s because it is made of a flexible rubber to make it more forgiving when hitting rocks as well as more durable. We recommend sticking with flexible fins in river situations if you want them to last any reasonable amount of time.
This fin is a great choice for lower volume, shallow rivers. It’s important to remember, the shorter the fin the looser the board. The board will be easier to turn but you may have to work a little harder to keep your board paddling in the direction you want it to go. For lower-volume rivers this isn’t much of a problem. It’s the big pushy stuff where having that extra fin really comes in handy.
Now, let’s get into side fins, also known as, side bites. These side fins come in pairs and live on the right and left side of the center fin. The side bite fin boxes are fixed a few more inches toward the horizontal center line of the board. In most cases, if your whitewater board has ample tail-rocker (which it should), these fins will sit a little lower in the water than the center fin because they don’t have that rocker to give that little extra lift.
These fins are great to use in conjunction with your 4.5″ center fin in big water where directional stability is very important. Weight may also be a factor in deciding which fin set-up is best for you. A bigger paddler may have an easier time maneuvering a longer fin set-up versus a smaller paddler. It’s always good to experiment with different configurations and see what works best for your style and size.
These little guys here don’t seem like they would do much, but a little can go a long way when it comes to fins. When running a 3″ center fin these can be helpful in adding a little extra bite when paddling shallow rivers. Or, using these in configuration with your 4.5″ center fin when you don’t necessarily want to go as big as the 4.5″ side bites. If, for example, the river your paddling is pretty technical and you need to make a lot of quick moves in a rapid that could be a perfect set up.
Another option is using only the 2″ side bites and no center if you find yourself paddling a very shallow river, because something is usually better than nothing. Smaller paddlers paddling on 9’6″ whitewater boards may opt for these fins more often than 4.5″ side fins so less power is needed to lay into the rails of their board to make an eddy turn or change their angle.
Center Fin Screws
We recommend stocking yourself on some back up center fin screws because you will lose them.
Grub screws are used in your side fin boxes. Your side bite fin boxes are click fin boxes (if you’re paddling a Rivershred), meaning you can click your fin in without having to search for a fin key and secure them with the grub screws. In a pinch this is great when the frequent disappearing fin key is nowhere to be found. BUT, we recommend using the grub screws that come with the fins when you can. All it takes is a couple blows to some rocks to pop those fins right out.
Fin Keys! Fin Keys! And More Fin Keys!
The precious fin key! Get lots of these! Keep one on your key ring, in your lifejacket, in your shoe, under your car mat, around your neck, on your dogs collar. You never know when you’re going to need one and they are never where you thought you put them.
That should get you started! And remember if you have any questions about fins or gear you can message us directly on our website or e-mail us at firstname.lastname@example.org.