Greenough 4a fin - can it be salvaged?

I made a fin from a Greenough 4a template using 50 layers of 4oz cloth. To skimp on cloth, I laid it up by “stepping” it. I’d done it before and made great fins.

Well It seems I went wrong somewhere this time. After foiling, the fin fits the box perfectly, but it’s really thin and the flex is ridiculous. Almost like rubber.

I don’t know if it was the 4oz. cloth or the way I stepped it, but can the fin be salvaged? I was thinking of just laying some layers of 6oz. on both sides to stiffen it up and give it a little more thickness.

Or is a 4a supposed to have a huge amount of flex? I remember the fin Greenough was using on his edge board seemed to have a lot of flex. wasn’t a 4a but im just sayin’.

Try it out in the water, you’ll never know, it could be a winner…

If not chuck some more cloth on it…

good answer!

I don’t think you want a huge amount of flex so it flexes “like rubber”. You want the type of flex that creates tension and snaps back like a bow. Does it have a good “twang”? I would probably try to stiffen it up with more cloth then re-foiling if it is too soft.

Jim

If the foiling is good, cut out the middle of the fin & fill it with hardwood like John Cherry does. Only takes a new 1 or 2 layers of glass over that to finish it. The leading & trailing edges are great guides for foiling the wood, and wood’s easier to foil than fiberglass anyway…

Hicksy has a got it. George is an very unique surfer and either made his fin with specific characteristics to suit himself or had a stab at it and just rode it.

Ride it… if too flexy get some uni-directional glass and add it to suit . There is no secret formula and you will be either happy or still looking for answers in a year from now.

You could try George, somewhere around Lennox Head Australia.

Quote:
Or is a 4a supposed to have a huge amount of flex? I remember the fin Greenough was using on his edge board seemed to have a lot of flex. wasn't a 4a but im just sayin'.

Yeah, I’d surf it.

Then add layers of glass and re-foil as necessary.

Flex makes a huge difference in performance of singles.

What kind of board are you going to use it in?

Recently put my Greenough 8" 4A into a 7’ pintail and found it lacked hold. The original fin which had less flex and more tip area felt positive all the way.

Yet the Greenough in a 6’4" roundtail has never even felt like spinning out even with the fin right forward in the box.

May be just the ticket for a hull shape.

i agree, go surf it—then either add a strip o f carbon tape on each side or just more layers of e glass and refoil-----i used to sit on the beach and sand the fin --go surf it and sand some more —surf it----etc–etc ----ruined several but ended up with some super foils too. i think its called ‘trial and error’?

try the Fibre Glas Fin Co. version of the greenough 4a template…it has a bit more of a spine on the leading edge…still flexes nicely at the tip, but doesn’t slide out so much like the greenough.