What is the most universal finbox?

Just wondering what the most common finbox or boxes are for big singlefins, and what options are available these days, I suppose I should know this but I haven’t ridden a board with a box in the last 10 years so am kind of out of touch with it.

Any help will be much appreciated.


Probably the most universal fin box is the Fins Unlimited 10’’ box, developed by Bill Bahne.

Diddo. If it aint broke, don’t fix it.

No reason for me to worry about anything else out there for single fins, because the cheaper molded fins, and the fiberglass fins to fit those boxes are muy plentiful around here.

double that Ditto…

Careful. I’ve had both the Bahne’s correct me that the 10" ‘box’ is really a 10" channel. :wink:

I knew that… actual outside length, 10 1/2’'. Just won’t let me be lazy, will you?

Fins Unlimited 10" or “Multi fins” 10" in Australia. Chinook boxes are incredably strong or so i’ve heard…

Thanks !


I see that the fins unlimited site has the dimensions of the box in plan view but not from the side, I need to know (please) how far down from the top of the box the horizontal slot is, and what the pin, plate and bolt dimensions should be, or a side view of a fin made for the fins unlimited box (with dimensions) would be cool. The fins unlimited box looks just like the old 70’s boxes we used to get.


It is the same box, in basic form, since 1970.

Hmmmm, as I recall there was a slight problem with the screw head sticking up into the waterflow, do you guys countersink the screw heads these days to get them out of the way or does that take away too much strength from the fin tab ? I always wound up packing my fins with newspaper to stop them flapping around because the fins always seemed to be narrower than the box.



I never had any problem of any kind, with the Fins Unlimited box, here under discussion. My experience is limited to about three thousand units. Perhaps I just haven’t been in the trenches long enough. You think?

I never worried about the screw heads with all the empty area in the box, …er… channel, behind and in front of the fin. I have seen fins that are a little loose and guessed that was from the installer kicking the poly resin too hard.(?) You could always paint a coat of resin on the sides of the fin base to tighten it up

Only 3000 units Bill? Rookie! (Joking).

Hi Bill,

No problem with the box implied, just the fins being made too narrow, and packing with paper used to fix that. Might try countersinking the screw head.

What I am really after is a side view of the fin base, with dimensions.


Chinook strongbox for sure, especially if you use fins longer than 9", or occasional run aground.

Can be posted thru to deck, are one piece, twice as thick, and corrugated for better resin adhesion.

Tiny fins need not apply.

Hello Roy. The screw does stick up a bit. Doesn’t seem to screw it up, though. I remember sticking matchbooks, matches, any little thing I could find in the sand to snug up the fin in the boxes back in the seventies. Honesty, don’t know if they were Bahne’s or some other manufacture that used the same set-up. Maybe I should bug out of this. Of course, I defer to Mr. Thraikill. Mike

Bahne box’s tended to widen with use, till the fin fits loosely. Made from several pieces, unreinforced, and oftentimes surrounded only by the double stringers of the board.

Screw head sticking up don’t matter, you can ride with a fingertip dragging and not loose any distance.

i drew this a long time ago but never completed quality assurance review and data validation, so cannot promise the measurements are correct.

Thanks SOUP, here’s your drawing:

I can’t seem to find a 10" Chinook fin box anymore. I also like them because they are not only strong, but the way they are cut really holds up nicely.


Fins Unlimited 10" or “Multi fins” 10" in Australia. Chinook boxes are incredably strong or so i’ve heard…

No problem with screws for me - I don’t use 'em :slight_smile:

Go for the fins with a front scew tab - there are plenty - and just make sure it fits tight. If its too easy in & out, wrap the base with some masking tape or a piece of plastic sheeting. No problems at all with it coming loose while surfing. And if you hit a rock or something, the fin just pivots out on the (rear) roll pin. No finbox damage, rarely any fin damage. Easy to adjust in the water, too. When I find a fin I really like, if its too loose, I paint a bit of resin on the sides & then sand it down until it fits firmly again.

Never, never lost a fin that way.