Fins for River SUP

 In Gear


The use of fins on standup paddle boards in rivers is an evolving aspect of our new sport. The use and types of fins available for stand up paddling in the ocean or flatwater is pretty well established so I am not going to spend a lot of time talking about fins in flatwater or the ocean for this post.

First some fin basics. Fins work to help the board glide on a straight line. You can think of a fin as allowing you to transfer the power you put into a paddle stroke, in the forward direction versus a turning direction. In general longer fins make a board track straighter than shorter fins and short fins allow a board to turn more easily than longer fins.

When surfing, your fins and fin configuration allow you to turn the board on an edge without slipping. It is possible to paddle and surf finless with a combination of advanced paddle strokes and foot position on the board, but paddling becomes more difficult without fins. I’ll talk more about paddling finless later in the post.

Another general note about fins. Fins are accessories to your board. We, like a lot of SUP companies, provide fins with your board when you buy a new board, but your fins will break, get lost, or you may want to have some options for different types of fins; so plan on buying some back up fins and putting together a fin quiver so you are ready for whatever type of paddling you might encounter. All the fins mentioned in this post can be purchased on our accessories page.

For whitewater river stand up paddling we only recommend using soft flex style rubber fins. These fins flex when they hit a rock, which increases your chances of not damaging your board and gives you at least a shot of staying on the board instead of launching superman style into the river.

Soft Flex Center Fins in 4.5″ and 3″

Rivershreds come standard with a 4.5″ Soft Flex center fin and 4.5″ click fin side bights. We do sell a 3″ version of the center fin if you want to have a shorter option for shallower rivers as well as 2″ Click-Fin side bights. Click-Fin side bights are a cool new way to change the fin configuration on your paddleboard.  Click-Fins slide in and click in place and can be secured with stainless steel grub screws (See video below). Click fins on your Rivershred give you a lot of options. You could paddle with just the center fin if the river is shallow or you don’t want to worry about hitting the side bights. Or you could add the side bights when you want additional tracking or if you know you are going to surf, but the important thing to remember is just because your board came with three fins doesn’t mean you have to put three fins everytime you paddle. Make fin choices based on conditions and what type of paddling you are doing that day.

The I-SK8 comes with three Click-Fin boxes and three 4.5″ Click-Fins. With a surfboard you make decisions based on surfing performance. Putting all three fins in will make your feel “stiffer”, in other words the board will not turn as quickly. This is a good thing when you are learning or when you are surfing a new wave as the board will not want to slip out on you and will feel more predictable under foot. When you want the board to feel “looser” or turn more quickly you can start by removing your center 4.5″ Click-Fin and replacing it with a 2″ Click-Fin in the center box. If you really want your board to be loose so you can surf like Miles Harvey you could pick up a couple sets of 2″ Click-Fins and surf only 2″ fins. The point with surfing is that fins radically change the way the board surfs so you can play around and find the set up you like for your weight, your style and your wave.

River Surfers and SK8’s are set up with a tri-fin or thruster fin configuration because the boards are meant for park and surf paddling and a thruster gives your board more speed and agility while surfing. Riding your River Surfer tri-fin will give you more bight and make your board feel “tighter”. Taking out the center fin reduces drag and gives your board a more “loose” feel allowing for tricks like 360’s and Shuv-Its.  Check out these two river surfing videos featuring Badfish Pro Mike T for basic and advanced river surfing technique tips as it relates to fins. We only recommend using soft flex fins with your River Surfer, but it should be noted that experienced river surfers do use glass flex or “hard” fins. Composite fins give you many more options for sizes and types of fins and are higher performance, but increase the risk of damaging your board when and if you hit a rock.

Paddling Finless
Many experienced river paddlers choose to paddle on the river finless. The benefits of paddling without fins are obvious…nothing to hit rocks. The downside is also pretty obvious….the board won’t paddle straight. Advanced paddle strokes allow you to compensate somewhat for this lack of steering and in more technical rivers you are never going straight anyway, so in some cases paddling finless is an excellent choice. I recommend practicing on river runs paddling finless by taking off your center fin (and side bights if you have them) at some point on a river run and try some basic river maneuvers finless. The more you practice, the more forgoing fins will be an option for you when the river dictates.

Fins are evolving for stand up paddling in a river so share your ideas and tricks with us too.
See you on the river. -Mike Harvey, Salida, CO



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