A few days ago, I was cleaning my SUP after a nice paddle in the river when my neighbor walked by and asked if I really needed that big fin on my SUP. I told him that I wasn’t quite sure, but I thought so. And that was the conversation. But it got me thinking, and I had to go out and try to SUP without my fin. This is what I found out.
You do need a fin on a paddleboard to make it maneuver properly. Without a fin, you would spin around in a tight circle. The paddleboard fin also adds stability to the board.
My little experiment was fun, and I learned something new. I had a pretty good idea of what would happen but was surprised by how much not having a fin affected the board’s performance. Read on if you want to learn more.
Three other factors affect how the fins work. They are:
1. Fin Size
The bigger the fin is, the more force it can exert on the water. So, the bigger your fin is, the more stable your board will be, and the straighter it will travel.
SUP fins come in several different sizes. Most single-fin boards will have a fin between 8 and 10 inches. This has been precisely my experience because every single-fin board I have purchased has come with a nine-inch fin standard.
A SUP can have multiple fins, as you will read below, and these fins can be placed in a variety of configurations. Generally, the middle fin in most construction will be larger and range in size from 6-10 inches.
There can be side fins, and those will generally be smaller than the center fin; in the neighborhood of 3-6 inches. With a three-fin setup, your stand-up paddleboard will be more stable than a SUP with a single fin.
2. Fin Placement
I had to thank my neighbor because I learned something that really helped me out while I was looking into this. Fin placement affects how maneuverable a SUP is.
I found out that on boards with removable fins, the fins can be placed in different places. I always slid my all the way forward because I just thought that was how it needed to be.
It turns out that sliding the fin all the way forward in the fin box will make the SUP more maneuverable. If you slide the fin to the rear of the fin box, the board will track straighter, which is better for touring. Having the fin forward will give SUP surfers added maneuverability.
3. Number of Fins
As I mentioned above, a SUP can have multiple fins. They can be configured with 1,2,3, or even 4 fins.
The single fin configuration has just one large fin placed in the middle of the board.
A 2-fin board usually has equal-sized fins left and right of the centerline.
The 3-fin SUP has a single large fin and two smaller fins on each side. Some boards will use three equal-sized fins in the same configuration.
Finally, the 4-fin setup has either two fins of equal size on each side of the centerline. Or, have one larger fin followed by a smaller fin on each side of the centerline.
The more fins you have, the more surface area, and therefore, the more stable a board will be. The added surface area diminishes the maneuverability, so turning will take longer, but tracking will be better.
With all of that being said, for a beginner, there isn’t really a bad choice. SUPs will generally come standard with 1 or 3 fins, and their effects, while measurable, are minimal.
Findings of My “Tests” Summarized
Just for fun, I decided to do a little test. I would take ten big strokes with the fin on. Then I would come back to the beach and take the fin off. With the fin off, I would go back into the water and take the same ten big strokes.
Then, with a little more research back at home, I found that a fin acts like a keel on a sailboat. It helps stabilize the board and allows it to travel in a relatively straight line. Basically, the fin pushes against the water to help keep the tail from sliding to one side.
I’m glad my buddy asked about fins. It was fun to test my board out, and I was shocked at how nearly impossible it was to make any forward progress.
I’m also happy that my touring setup is now a bit better because when I’m out on flat water, I move my fin all the way to the rear, which keeps my SUP going straighter.
Hope y’all learned something too.
Are SUP fins interchangeable? A lot of SUP companies have gone to interchangeable fins for THEIR boards. So, if you bought a Brand A board, you should be able to get different replacement fins from Brand A, but not necessarily from Brand B.