making beaver tail fins for my fish ( ( i love beaver ))

General Discussion
1

Ive been runing a 10" beaver tail fin on my 9’4" longboard for a year its a midget Farley design and gives the board great drive through turns compared to any other single fin set up ive used cant find any negative about it.

So ive started to make some for the fish a freind made for me ( thats right i bought one instead of making one for a change ) its not exactly what id do for my self.

In saying that its just small stuff that can be tweeked with a cup of resin and a sanding block, the rail edge in the tail needs sharpening and the d fins have no flex at all so they had to go.

Im expecting with these small alterations it will go faster than a fish normaly dose 

 

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3

Looks good, let us know how they go. Toe-in and cant? Glass ons or fin plugs? Foiled both sides?  Also curious to know how much difference that hard edge makes, let us know on that, I’m skeptical.

4

2 layers of 200gm carbion kevlar 1 / 5.5 s glass with 10mm glass roving leading edge for extra spring

The core of the fins is a type of ply wood used in racing yachts Gaboon ply you should be able to get some off cuts from your local boat builder its about the weight as balsa wood but alot stronger 

5

Glass on ,

8 degrees cant

Tow in is a secret(close to streight fin space 6" off center tow will be 5" off nose

6

How’s foliling that Kevlar?

7

The ply is foiled the kevlar is laminated over

8

I thought they looked like wood.

Wondering how much stress all that tip puts on the fin base.

Glassed on or fin system?

They look cool.

Would like to try that design.

9

There will be heaps of stress but i do have a tried n tested plan that i will unveil over the next week of so

10

http://www.farrellysurfboards.com/12-farrelly-cutaway/item/12-cutaway

Link above will explain why im mimicking the concept

11

?

Leading edge is ground off to alow for continuose roving to add strength and give the kevlar / carbon a better structure to bond and pull against.

Also note the groove runing vertical from base of the fin,

Will hold roving that will run a cross the board to help hold the fin in place (?)

This will make more sence when we get to laming the fins on.

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12

Some type of reinforcing tab, maybe like a Popsicle stick, to strengthen the attachment to the foam?

13

Hi huck i edited the previous for your curiosity.

Picture shows the amount i cut off the leading edge and back of the fin for continuose roving

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Fin with lamination stretched so when i turn them over ti will alow a groove / void for the continuose roving edge .

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Fin with lamination stretched so when i turn them over ti will alow a groove / void for the continuose roving edge .

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Fins turned over with continuous roving edge layed in the groove

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Single lam over

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18

Nice, keep the posts coming.

19

Dont be to concerned if the foil is a bit out of shape a good thick coat of filler resin before sanding will help humer out the imperfections .

Once your filer resin caot is dry ( if you don’t wait until its dry the surface will wreck your  texter / marking pen) take your time  using the fin temples draw a line around the fin.

Im waiting 4 days for the fins to cure properly because. 

The job will have a very  big chance of delamination between the glass and wood from sanding heat  

Waiting will also help when reshaping because it will minimize over sanding

I could sand them back to shape by hand to eliminate this problem but itd probably take 4 days

Fugure  6

 

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20

Fins are sanded to shape apart from th front edge needing a bit of a touch up. With the next stage ill link you to a new thed  ( how to make your own hydro skipper vacuum baging machine / start to finish and powered by a natural force non electric made from discarded ribish.)

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