Summary

About a year ago I shaped a 12' SUP to use as a frame for a hovercraft. I decided to go with a different frame that doesnt tip so easily for my hovercraft and am now left with a 12' SUP. Being that I love SUP'ing and was already in the market to buy a second SUP for my wife, this worked out perfectly. We took it to a lake this weekend, and it performed great accept that it didn't have a fin. So I designed this fin to be attached to a board without a fin box. I am going to epoxy/screw 1-2 of these to my SUP and will report back how it works and how it looks.

I plan to run this through my acetone vapor chamber (for added strength), and sand it aggressively. I believe that the trailing edge should be sharper than it is in the model. Will have to see what it looks like after it prints.

I am not a fluid dynamics engineer, nor an excellent surfer/SUP'er however I think it should be decent which was my goal. I didn't want to take this to a glass shop and have a fin box installed, so if you need a fin and dont have a fin box this may be for you!

Some general fin basics:
There are lots of fin configurations. I do Surf my SUP's but I also have a SUP that is perfect for surfing so I probably won't be riding this board all that much in the waves but may occasionally. For that reason I am using 1 large fine with no cant. This fin is not really well suited for 2 fin or 3 fin (thruster) setups because the fin rides perpendicular to the board. Most thrusters use a different foil design, are toed in, and smaller than the center fin, which makes this a poor choice if you want a thruster.

If you want a stable fin that is fast, and good for large boards and beginner boards, this should be an okay design for you.