Quad fin predicament...

Going short and stubby for knee to chest high. Thinking of going with a quad set up with futures boxes. I already have two twin fins that I was thinking about using as front quads, and am about to order rear quad fins. Am I going too big with a 5.37" tall and 5.25 base for the front? Was recommended to put them at 11"’ up from rear. With such large fins for the front, what do you recommend placement for the rears (if any)? Should I order smaller rear fins than 3.9" height and 3.85 base?

Also, any recommendations for cant degree?

Hope that all made sense.


For “on the rail” quads, search for Probox Larry’s placements otherwise search for the McKee placement…

I tend to put the big fins in the back and the smaller fins in front like a twinzer.  I always start out with big fins in front, but I switch them at some point.   I guess I just don’t like the skatey feel and want more drive…

The disclaimer is that I like single fins and Bonzers more than tri/quad fin setups.

Imo, for a wider tailed board like that, you’re gonna want a rail finned setup.

Larry’s placement numbers are great.

Regarding Da5id’s comment about skate vs drive… generally speaking, big in front small in rear will give you skate. Big in rear will give you drive. Close to same size will be somewhat in the middle. And you can get every shade in between. Obviously, there is the option of moving the whole cluster forward or back also.

This is one of the reasons why I don’t like futures.

You cannot move your fins at all and you are limited by what is available for the different depth boxes.

Hey Chrisp;  I didn’t know Larry had some reccomended placements for on the rail.  I haven’t been following his blog.  Can one of you guys link that info or direct me to it.  There was an old thread on here about placement that Robin contributed to a couple of years back.  I’ve always used on the rail placement and a particular placement, but looking to change things up lately.  Lowel 

Hey Lowel, iirc, Robin’s placements are similar to Larry’s…

I don’t follow Larry’s blog either. He had posted his fin placement numbers here on Sways.

I’ll see if I can find 'em…

Here are some threads that discuss Robin and Larry’s placement numbers.

I liked my rail finned quads MUCH more than the McKee setups that I tried.

One board started with a McKee and I switched to a rail finned quad and it was amazing how much better the board went. From what I’ve read, rail finned quads require single foiled fins. Griffin puts his quads on the rail too… There is just something about 2 fins on the rail that just feels SO good in a turn. Especially trying to project down the line.

All of that said, the Griffin 5 setup blows doors on quads imo.





Thanks--  I’ll be checking those out.  I remember in one thread Robin and I were on the same page placement wise.

I don’t always make wide tailed quads.

But when I do…

Mahalo Huck…

Those numbers look kinda far off the rail Matt…

Have you tried them closer to the rail?

Not being a smart ass…

Or too hippocratic 

Yeah, I move them 'round a little

It would be hard to suggest fin template and size without knowing what placement and toe in

you figure on. A perk for FCS is that custom fins can be made with fin tabs anywhere on the fin base.

For my part I favor the front tab right under the leading fin edge. However this isn’t a standard FCS

placement. As far as choosing a set up there are several ways to go.

A) twin keels with them set well back and close to the rail this arrangement works well in small

surf and does a quite adequate job of propelling the board for speed. It’s also nice and loose if the

fins are canted properly.

B) Twinzer set-up is very possitive and drivey if placed properly. It can be loosened up quite a lot

for mushy conditions just by removing the canard. Breaking the tail out more easily as a result.

C)  A middle of the roard Quad is IMHO a set-up the shines in larger steeper conditions. Lead fins do best a little larger than standard thruster rail fins with greater cant  of 2 to 3 degrees. Trailers work best smaller than the lead fins by an inch or so an should run with about 5 degrees less cant than the lead fins. Foil on the trailers has proved excellent at 70/30 though I don’t think such foils are available off the shelf.

D) a little spade in the center can prove a valuable addition as waves get bigger and more demanding

with any of the three above set-ups.

I have photos of some set-ups once you make a fina decision on what you’re going with.


Stay Stoked, Rich

Thanks for the advice chrisp, I will definitley do rail finned. Sounds sick! I’ll have to play around with fin placement, you got me thinking large fin back on toeside for a drawn out bottom turn and large fin forward for the heel side for a quick snap at the top. hmmm

Chrisp has me sold on a rail finned quad set up to coincide with the wide tail.

From what I have gathered up to this point, I am currently planning to have rear fin 6" forward from the tail, and the front fin 11" forward from the tail. (I am leaning towards having the large fin forward, however I also want to test out the large fin in the rear before I come to a conclusion.)

Both front and rear fins at 1.25" from rail.

Toe at 1/8" for both front and rear. (After reading Larry’s probox blog, I agree that the fins should be parrelel with eachother regarding toe.)

What do you recomend for cant for both fins?

This is all a rough draft at the moment, and I am not opposed to any recomendations/ changes

I have made several similar boards and if it were me on a 5’6" I’d spread out your cluster a bit more, and move the whole cluster back a little also. Front and rears are too close together IMO and you will have a very pivoty board but not alot of drive, which you will need on a 5’6". Also on a board so short, I’d have the fronts a bit further back than 11".

If this were my board I’d do:

Fronts at 10.75"; 1.25" from rail with 1/4" toe in.

Rears: 5"; 1.5" from rail with 3/16" toe in.

Your choice of fins will also obviously make just as big a difference as the placement. These Green FCS guys were made for your kinda boards—short with wide tails.




Fins are called FCS Compressors. Not highly promoted by FCS, but great if you can find them. Tons of surface area for drive to match wide tails/short rails, but very upright for looseness. They are old two-tab fins, not FCS II. I have them screwed into the FCS II boxes.



I like Jamie’s numbers for distances from the tail.

But, I’d put all of them 1/4"ish closer to the rails.

So, fronts at 1 1/8" off and rears 1" or even slightly less off the rail.


As far as cant numbers… 8* for both or 8* front and 6* rear would be good.

Rail fins are ankle chewers, I move my rears in a tad for that reason. Everything is a compromise. Can’t recall which board that pic is from Matty posted but pretty sure it’s one of mine.  

I’ve been running 6 and 4 on my cants, but with probox its adjustable. I did try 6 degrees cant all around on one of my quads, but it felt a bit tracky on faster waves, going to 6 & 4 seemed to loosen it up just right.

I recently made something very similar to your board and just got some ride reports, so becasue the board rides extremely well, here are the numbers I used:

Front fins

  • 10.3" from tail,

  • 1/4 toe, cant at 6.5°

  • 1" from the rails.

Rear fins

  • 4.5" from tail

  • 1/8 toe, cant at 3.5°

  • 2" from the rails


I agree with Huck about fins too close to the rail being “ankle chewers”. Seems like 1" from rail is really close, especially with high cant angles. Those blades will be sticking out and you will be surprised how easy it is to nail your ankle bones when you spin to paddle for a wave.

Meh… I’ve been surfing rail finned quads and Griffin 5’s for several years. With SHARP G10 fins at that. I can count on 1 hand the number of times I’ve cut my ankles with them.

The performance far outweighs any perceived dangers.

You guys should see the fins sticking out the side on my twinzer.


Huck, I had the opposite experience changing cant around. More cant felt looser. Less cant was stiffer and drivier.