Fins for River SUP

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.

My guess from where I sit today is that this post will be obsolete within three to five years because some sort of norm (a new type of fin, way to attach a fin, paddling with no fins) will have taken over for river SUP.  That said here are some techniques and types of fins that Badfish SUP recommends for paddling our stand up paddle boards in whitewater river environments.

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.

Fins for Epoxy Boards

You can check out a general video talking about fins on our You Tube page here. Our epoxy boards come equipped in three different ways. The 9′ and 7’6 MVP’s are equipped as 2+1. This means a long board style center fin box with two side bight boxes.  All of our epoxy boards are set up for FCS and FCS style fins. There are other fin systems, but FCS has a lot of fin choices and other fin manufacturers use their standard attachment system. The 10’6 & 12’6 MVP-X are single fin, meaning the board is only set up with a center fin box. The River Surfers come as thruster or tri-fin configured which means three of the 2 tab, side bight style, fin boxes.

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.  Hitting a rock with your fins can cause damage to your fin boxes even with soft flex fins, but fin boxes can be repaired, usually with readily available materials. There are tons of resources on the web for repairing fin boxes so I won’t go into details here.

MVP’s come standard with a 6″ Dolphin Soft Flex center fin and M5 soft flex side bights. The basic way we paddle downriver on our MVP’s is with a single fin only. We only use the side bights when we plan to surf a lot or in big water where we want more tracking ability. The reason is that side bights are easy to hit on rocks and most of the traction comes from the center fin anyway. On shallower rivers we use modified center fins that we cut down to 3″-4″ with a jig saw. Here is a short video that shows how we cut down center fins.

For most paddlers I recommend purchasing an additional 6″ Dolphin Soft Flex fin that you can cut down for paddling on shallower rivers.  FCS makes a an adaptor box that converts a M5 side bight fin into a fin you can use in a center fin box. I have never had good luck with these adaptors. I find that the tabs pull out of the box with even the smallest bump and you end up going though a lot of fins. FCS also makes a 9″ soft flex which is too long for almost any river scenario, but is a good choice if you are going to paddle a lake with a rocky shoreline where you have to be concerned with bumping rocks while paddling to and away from the shoreline. Both 6″ dolphin fins and M5 side bights are available on our webstore.

6" dolphin soft flex fin comes standard with Badfish boards

6″ dolphin soft flex fin comes standard with Badfish boards

A dolphin soft flex fin cut down to 4" for paddling on the river

A dolphin soft flex fin cut down to 4″ for paddling on the river

OCTOBER 2014 EDIT: We recently added a new type of river fin to our accessories store that is going to be the standard river running center fin on all our boards in 2015. It comes in 4.5″ and 3″, is made of the same soft flex material the FCS dolphin above is made of and has a great, raked, shape for river running. This is all we have been using since we discovered it. You can buy them right now to retrofit your board’s standard center box at on our accessories store.

river fin fins whitewater stand up paddle paddling river running

These soft flex river fins will come with Badfish boards in 2015.

River Surfers are set up with a tri-fin or thruster fin configuration because the boards are meant primarily 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/Boardworks 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.

Fins for Inflatable Boards

Our inflatable paddle boards, like the MCIT and Badfisher, come with what has become a fairly standard fin configuration on inflatable stand up paddle boards. The glue on fin boxes are set up as a 2+1 configuration with a removable plastic center fin and two, small, rubber 2″ side bights that are glued to the board. In whitewater environments or shallow water fishing scenarios like flats fishing, leaving the center fin out allows you to effectively paddle finless while still maintaining some traction on the water. The boards come standard with 9″ center fins for flatwater and the ocean. We used to cut down these 9″ center fins for whitewater, but NRS makes a great 5″ and 2″ version of the center fin which you can order from our webstore here. We recommend that you purchase at least one of each size so you have options when you are out paddling. If you are going fishing or stand up paddling somewhere remote (flats fishing in the Yucatan or a multiday river trip down the Green River) make sure you have back up fins. These fins are meant to fail at the base and avoid damage to your board and the fins are cheap so buy some back ups and pack back up fins.

2" and 5" NRS Center Fins for inflatable SUP's

2″ and 5″ NRS Center Fins for inflatable SUP’s

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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Badfisher stand up paddleboard SUP fishing inflatable fish travelMike Harvey casting off the Badfisher inflatable fishing paddleboard.