12" or larger fin source for standard fin box

Put together a SUP…I thought it would collect dust, but it is a hoot.

I’m using a 10" big-daddy rainbow fin at this time…(largest one I had in the fin stash)

Searching for a 12" fin with a similar outline / template of the big-daddy rainbow. (wide base)

Does anyone know of a source?

I’m almost at the point of laying up some glass, and making one myself…

Thanks,

PBM

Bob Person, (Arrow surfboards)had a real big Rainbow fin made I think it was 12" check with Rainbow fins.

You built the board yourself, try making a fin as well…

That is where I’m going…I was held hostage by blanks until clark went away…EPS hot wired blanks, and eps foam billets straight from the source…PRICELESS

Now…I’m taking on building some fins…I have a lot of glass sheets available, and in the next week or two I’m laying up some fiberglass sheets…24" by 60"…Thickness? how many layers will be the correct amount “experiance is expensive” LOL

pbm

Chip knows the formula but I’m pretty sure he lays up around 36 layers of 6oz…

Good luck with your experiment…

try calling rainbow fins and see if theyll make one for you for a few extra dollars.

The number of layers depends on how wet you lay them up, and your technique. For a box you’ll likely need about 32-plus layers.

The real hassle of FU boxes is tooling them to the exact thickness, with parallel faces, so they don’t wobble. Unless you have a bright idea about a mold, or maybe a router table, I have not tried to make box fins in a long time.

Hey box fin makers, how do you tool the base to the exact thickness?

I’d look into SUP stores if any in your area, for large fins.

I’d also suggest you really may not need a 12-inch fin, but whatever floats your boat…

The reasoning behind the 12" fin was the board was tracking when I was 2 foot from the nose on some mushy (but long waves). I was looking for some more holding power to lock into the nose.

I’m looking into router techniques, and have talked to the shaping / glassing friends about it too. 32-36 was the amount that we were talking about. Ironically, I replaced some large windows at my house. When I was pulling them out I said…“This glass will be great for laying up some fins. Put them by the work shop” (That was two weeks ago)

The fins unlimited box is critical. Machining it consistantly is key…

pbm

made a number of larger templates for 12’ boards

rainbow guys fabricated six batches for me

I have probobly 30 in stock

point of diminishing returns on largggeeee

area fins…

fin box failure

or perhaps enginineering allows fin box rollover

area ?

aint all there is.

if you must learn area lessons first hand

I recomend highly that you reinforce finbox side wall support

------------------------l F l----------------------------- allow wood to surround box beneath

------------------------l I l----------------------------- <cross section stringers 1/4’’

------------------------l N l----------------------------- perpendicular to stringer

_l_l_l____wood engineering side support

____________________________________________ to prevent box sidewall blow out.

…ambrose…

Priceless…

That is one thing that I was not thinking about…Fin box blow out…I had one blow out on a 10’ 8" (customer)…WTF happened here…Physics!

Ambrose…Thank you for the info. That was very valuable!

PBM