Thinking about tiny fins near the tail

I remember Bill Thrailkill mentioning to me that he had experimented with putting tiny fins at the tail of his board near the edges. He claimed that it worked great.

I really love a single fin, and I’m building a board that I hope will go well at Rincon. Other single fin boards that I have tried only worked there if I went all the way down and did a full bottom turn. I have missed the section on a single too many times, and I want something that will get me going down the line right away.

Check out the fin configuration in the image below (ignore the sanding burn-through :joy:). Let me know if you think glassing those little fins on the back will work as I am hoping.

Note: I’m planning on riding the board before glassing on the tail fins. If they seem to help, then I’ll leave them. If not, I’ll grind them off.

Couldn’t hurt to try. Have you tried adding widow maker fins?

Or try a more vertical low aspect ratio fin with a pintail - allows easier turning midface. But still a single is a single, IMO they ride the pocket but don’t pump for speed like a thruster. Rincon tho, should be makeable on a single. Let us know how it goes!

The link should take you to the thread

Having grown up on single fins, it was a big part to take the drop and crank a hard bottom turn where the g forces would buckle your knees.
Perhaps you could embrace that?

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Also not to belabor the obvious, but I think this is pretty much the definition for why side bites are used.

The tiny fins are probably gonna be more nuanced than dramatic

I think those are too big, and maybe could be more eliptical. Kai Lenny uses several very small fins on the tail, very small, tiny things, but they are on his smallest boards.
With that tail shape and size of fin, I would just leave it as a single. If I wanted to add fins, I’d put them in line with the large fin, or just ahead of the single. like having the front of the single inline with the rear edge of the small side bites.
I prefer single fins in boards over 7’. If that board is over 8’, I’d leave it alone, and just mess with fins and fin placement. I’ prefer the Greenough 4a in 7.5", 8" and 9" lengths, and a 9" Greenough 4c or Skip Frye fin.

Kookamunga_surfshop from Instagram sent me this. Relevant.

https://www.instagram.com/p/Cs2XxSUrWA_/?igshid=MzRlODBiNWFlZA==

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Thanks for reminding me about Kai Lenny’s fin set up. Here’s what they look like on his big wave toe board. I think that since I will be going a lot slower than him I should have something a little bigger. I do think that I should probably cut mine down a little, though.

Goddang if I didn’t mention @HerbSpitzer’s Superchargers…here’s one:

@Swied doe Kai Lenny say anything about those finlets?

You’ll go so fast you center fin will fall off.

I had a chance to be in the water during a small swell with Kai. He’s a really nice guy and amazing. He was riding one of those short boards with the tiny fins along the tail. He was probably one of the fastest guys out. I dropped in on him on one wave because he was so far back I didn’t see him. Caught up to me in a flash, and when I said I was sorry about taking off on him, he just blew it off and said no worries.
Only a handful of pros surf that fast and thankfully, they rarely surf where I do. Must be those little fins.

Kai didn’t mention the tiny tail fins in the video that I watched. I remember seeing another video where he talked about them, but I can’t find it.

I’m still making progress on the board. It’s just going slow with work and all. Here is where I’m at so far.


Kai keeps his cards pretty close to his chest. He has a reputation for swimming after his board whenever he loses it, and he admits its because he really doesn’t like other people seeing whats going on with his boards. I saw a video some time back where he talked about the little fins when he first started using them, its been a few years. If he’s still using them, he obviously thinks they’re valid, but not sure exactly what for. May or may not be the same effect as Swied is after.

Herb sent my brother some of the super chargers years ago. They are bigger than what Kai uses, but almost the size of what Swied shows.
I think they might be worth trying the way Herb used them. They were in front of the standard fin.