OK so the answer to question (1) is, you measure the depth not the length. Right?

Nearly forgot: if you're going to use a pointer, try to stay away from slalom fins as they're too flat through the middle. When you angle them over to 40 odd degrees the flat surface area is increased, giving them no upwind ability and the dreaded spin out.
Weedies are best with minimal flex and a graduated profile, whatever problems you may encounter with a pointer will be increased when you tilt it over so iron out the problems first.

WELCOME WELCOME TO THE ITCH !!
THIS IS THE BEST THING I EVER GOT INTO U LEARN SO MUCH ABOUT FINS LIFT STABILITY ECT ECT .. AND MEET A **** LOAD OF GREAT!! TINKER-ES ALONG THE WAY...
MY ADVICE
(A) START BY GETTING AN OLD WEED FIN AND HAVE A GO AT MAKING IT BETTER
GENERAL CENSUSES IS THAT THEY HAVE NO LIFT AND THERE NOT STIFF ENOUGH
EASY FIX CARBON AND SOME EPOXI WITH A COUPLE OF LAYERS OF GASS... DEPENDING ON MATERIAL ALREADY ON IT.. THEN RESHAPE IT.. LOTS ON THIS SUBJECT TOO ..
IN THE MEAN TIME MAKE A MOULD OF A BOX PLENTY ON THIS TOO
AND HERE whitelionwindsurfing.blogspot.com/
ONCE YOU HAVE A GOOD IDEA OF WHAT U WANT U CAN START HACKING YOUR NICE G10 AND PLAYING AROUND

MY BEST FINS TO DATE SPWEEDY 21.. 45Deg HAS DONE 41.04KN AND THE OTHER ONE THE SPWEEDY 19.. 42Deg 40.98KN BOTH OLD FINS I FOUND IN THE BOTTOM OF THE SHED..
I USED TO HATE WEEDYS BUT NOW I'M GLAD, AND PROUD THAT I ONLY SAIL ON MY FINS EVEN IF ITS NOT WEEDY.
I'VE ONLY JUST STARTED TO MAKE BIGGER FINS MY NEW ONE A 26 I USE THIS FOR MY FALCON 110 WITH A 6.7 AND 7.5 RSR TOP SPEED SO FAR 36.6KN ITS GOT MORE
JUST IN THE PROCESS OF MAKING A 24 FOR THE CASP50 for the 6.7 and 7.5m

DECREPIT AND IAN ARE THE TECH BOYS GOOD TO LISTEN TOO FULL OF GOOD ADVICE ... ALSO KEEF IS GREAT WITH HIS LOTIONS AND POTIONS "even if the tips come a bit late"
THIS IS JUST TO NAME A FEW OF THE GREATS ! THERES PLENTY MORE.

I KNOW DECREPIT DOESNT LIKE THIS IDEA AS IT CAN DAMAGE YOUR BOARD... BUT TAKING THE FIN FORWARD IN THE BOX SHIFTS THE CENTRE OF EFFORT AND I LOVE THIS... AS THAT WAS ONE MAJOR REASON I DID'NT LIKE WEEDYS

GO OUT AND DO SOMETHING DIFFERENT EXPERIMENT !!

NEXT THING YOU'LL KNOW YOU'LL BE MAKING FULL MOULDS OF THE FINS AND LAYING THEM UP ... BUT TRUST ME YOU NEED A LOT OF TIME AND EXPERIMENTATION BE WARNED..
I HAD NO PRIOR KNOWLEDGE OF EPOXIS RESINS HARDENERS CARBON AND THEY CAN BE VERY FRUSTRATING... AND ITCHY !!ASK THE WIFE !!

TIP DONT LEAVE THE BACK DOOR OPEN WHILST SANDING WITH A GOOD SOUTHERLY BLOWING OR THE WASHING OUT

BUT ALL IN ALL VERY REWARDING GOOD LUCK WITH IT ALL.. LOOK FORWARD TO SOME GOOD RESULTS AND BEFOR YOU KNOW IT YOU'LL LOOK IN YA QUIVER AND THEY'LL ALL BE HACKED TO 45

disclaimer I know i cant spell and any advice given was learnt by experimentation.

no expert.... just good results and allot of fun

peace out ! sorry for shouting

lelos12345 said...


I KNOW DECREPIT DOESNT LIKE THIS IDEA AS IT CAN DAMAGE YOUR BOARD... BUT TAKING THE FIN FORWARD IN THE BOX SHIFTS THE CENTRE OF EFFORT AND I LOVE THIS... AS THAT WAS ONE MAJOR REASON I DID'NT LIKE WEEDYS

hey leo someones making oversized boxes to take your fins

leo said...

NEXT THING YOU'LL KNOW YOU'LL BE MAKING FULL MOULDS OF THE FINS AND LAYING THEM UP ... BUT TRUST ME YOU NEED A LOT OF TIME AND EXPERIMENTATION BE WARNED.

come on leo show us the mould and the goods

leo its a credit to to ya, it's not easy moulding a fin and keeping it all strait without twisting out of shape, not sure if i would try it

Just checked some fin prices online, and I have to say this DIY idea is starting to look VERY good...

Windxtasy said...

I need a weed fin for Safety Bay, Tuttle box, for my 85 Sonic with a 5m Koncept.
Any recommendations?

Anita try something in the 23-28cm range. Can't go wrong with a Flying objects weedster. See Paul at 2nd wind they stock them.

hey mate the reason i did a mould is because i got to something i loved and every time i headed down south another 3 mm would disappear so before i destroyed it i fixed it all up and made a mould ,... well two messed up the first one rushing and it twisted;-(
the second one i did worked a treat I've pulled three from it the third went in today with a few tweaks to compounds and lay up just to see the difference.
I'm going to make a mould of the 19 cm spweedy too as soon as i get time and money together it is a long process, but i am getting much better ;-)
look forward to results decrepit ... I'm just in the process of doing the 24 cm at 40 deg for the sp50 just need some wind for testing god NSW SUCKS !!

speak soon buddy

decrepit said...

Looks good Leo, I've been tossing up whether to try a mould or not, but I keep changing my ideas on shape.

Currently I'm trying fins with a curved leading edge, less rake at the base (30-35deg) and more at the tip (40-50de4g).
Mainly because our worst weed problem grows up from the bottom in shallow water.
The weed on the surface gathers together and forms dense "weed island" even a 45deg fin comes to a dead stop when hitting them. So the idea is to avoid the weed islands, and use a fin more upright on average.

lelos12345 said...

hey mate the reason i did a mould is because i got to something i loved and every time i headed down south another 3 mm would disappear >>>>>>>

That's the biggest problem with carbon, it wears away very fast. especially on our bottom growing weed, it seems to hold grit in it or something.
Even if you don't hit the bottom, the fin disappears around the tip.

I've tried a stainless steel insert on the leading edge, a couple of fins worked very well, but most of them have delamn problems where the epoxy joins the stainless.

G10 seems like a reasonable compromise, no trouble with bonding and it wears much better than carbon. So I've been cutting the tips off old fins and using them in my new timber carbon creations.

Bit hard to do with a mould though, I've also been experimenting with additives in the epoxy, but no real results yet.

decrepit said...

I'm going with keef on the next lay up 9oz satin see if it works ...

Richiefish said...

do you guys sail in swamps or something ????

Not quite richie, but the water in the shallows is nice and flat, I think the weed growing up from the bottom helps as well. There's plenty of deep weed free estuary to sail in, but if there's a reasonable wind it gets choppy. The shallow stuff gives at least another 2 knots with a suitable fin, otherwise the weed slows you down.