Help on Fin placement and type...

Huntington State · Post by **Huntington State** » Sun May 16, 2010 11:58 am

I'm in the process of making my 1st board.......5' 9" Rounded Pintail TriFin.....
Can anyone offer me some advise as to fin placement...and...Type of fins I should concider...

albert · Post by **albert** » Sun May 16, 2010 3:35 pm

what do you want the board to do?

do you want it to hold in on big days?
do you want it to bust loose at will?

horses for courses here... if you search through the archives Im sure you can get a good overview of this, this topic has been discussed at length many times.

Headwax. · Post by **Headwax.** » Mon May 17, 2010 4:57 am

hello HS, sorry I was just passing by and saw your question

fin position mainly determined by where you kneel

where you kneel will depend on your rocker mainly,
secondly it will be your foam crossection
thirdly the planshape

so if you can figure where you are going to kneel (kneel further back rather than further forward), stick the outside fins just in front of your ankles

for the back fin, use a box, that way you can tune the board

boxes are good at first cause you can put lots of diff fins in in different places

downside is weight and the fact that people will think poorly of you

in general, most people use bigger fins in the front of a tri

base gives you drive in the beginning of the turn, rake gives yyou d rive at the end,

less rake makes your turns pivotal, which is grande off the top but less grande off the bottom

try top get the trifimns close enough together so they act as one, don;t make the back fin act as a rudder cause that makes drag, get it to work as part of the fulcrum base -imagine your front fins as the centre of the fulcrum of your turn - the back fin has to work with them, not just go along for the ride

over and outr

sorry can't see what I am typing cauismy text box is made by fxcs er fcs sytems and is inflexabk

Huntington State · Post by **Huntington State** » Mon May 17, 2010 8:01 am

Albert,
What do I want the board to do?. I want the board to do what my old school fish (fins back, glassed in) doesn't do.. I want the board to to turn off the bottom without sideslipping ...I want the board to be able to drop in verticle,punch off the bottom with out losing speed....I'm getting bored taking off on a slight angle, "S"ing my way down the face at a 100 miles per hour,...I never actually expierienced a true hard bottom turns as I see you guys do....that is ...without spinning out.My fish works best when the waves have a long drawn face...point break type of waves....but most of the waves I surf are beach breaks...which are steep drops with workable bowls and then close outs....
Headwax,
I like your feedback on "fins in front of your ankles"...I'm a visual person so this at least gives me a idea of where to position the fins....you mention box in the back.....but not on the outside fins? is there a reason why...I would think you'd want to have as much freedom to postion the fins... to get it just right based on where you postion yourself .....and also you mention larger fins on the outside....is mainly due to the drag a larger fin may have if it is on the back?....
Also....Box type and fin type...so many manufacturers...Is there one thats more tailored to kneeboarders?...or my specific board....a Trifin
Hey Thanks to both you guys for the response...I know I ask stupid questions but ever since I found this site its made me dust off the old board....get back in the water...and get my stoke back...now I'm totally into my passion again...I know the board making process is trial and error but all the input you guys have is much appreciated!!!

crox · Post by **crox** » Mon May 17, 2010 8:34 am

Hi HS

You said - "What do I want the board to do?. I want the board to do what my old school fish (fins back, glassed in) doesn't do.. I want the board to to turn off the bottom without sideslipping ...I want the board to be able to drop in verticle,punch off the bottom with out losing speed"

This can easily be as much to do with body position....if you want to do the kind of turn that you are talking about you need to lean forward to engage more rail in the bottom turn & cutback....but you may need to kneel further back than you are now[maybe!]

Check the body position in the photos that you like.

If you sit back on your heels & upright the board might feel a bit squirrely.

Changing style takes time!

My tri fins are about 16 3/4" up for side fins [toe in is about 4" out from the stringer at the nose] & 8 1/2" up for the centre.

There is no kneeboard specific finbox.
They are not stupid questions.....ask away

Huntington State · Post by **Huntington State** » Mon May 17, 2010 9:26 am

Crox,
Tried all types of positioning..This of course is with my old school fish....drop in leaning forward full speed...lean back on tail ..once I hit bottom... tail slips out.....drop in with weight on tail...lose speed and squirrley as hell...
I figured the Trifin would give me the control I need with the 3rd fin...I never had a problem generating speed in all my years of kneeboarding ..its the side slippage off the bottom I have a problem with especially on my fish...I'm gonna layout your fin location and see how it looks...
Thanks Crox

crox · Post by **crox** » Mon May 17, 2010 10:07 am

I forgot to say...those measurements are to the back of the fin!

You need to lean forward right through the bottom turn. Try & look at the rail in front of your knees & make sure that is engaged.

analbirth · Post by **analbirth** » Mon May 17, 2010 1:08 pm

HS if you want your board to do all those things go for a quad.

Headwax. · Post by **Headwax.** » Mon May 17, 2010 1:31 pm

ha that's funny analbirth

HS, sure fin boxes for all three fins are great

10 inch, I think Dion in Oz still makes good ones/

I presently ride quads with boxes in the front fcs in the back, because in quads the position of the front fins makes all the difference

for me, with tris, the back fin was always the killer to tune.

But three boxes for your prototype is good. Box fins give better sturdiness than fcs I think. They also let you ride assymetrical set ups - which is how I like mine

You can also tilt them, just grind the tops off till they are flat with a belt sander (puts lots of tape around the boxes so you don't sand through the glass. The tape gives you a warning.)

cheers

headwax

PS what Crox said about style is spot on
PSS Chris hello, nice to hear you

Huntington State · Post by **Huntington State** » Mon May 17, 2010 1:36 pm

analbirth ...great name!
Quad will be my next project!

skansand · Post by **skansand** » Tue May 18, 2010 8:58 am

example: in my old 6'1 x 24" roundpin I like GAM side fins and a G3000 trailor for up to 6', or GYU for Bigger waves to like 10' faces...

my 6'1 x 23 pintail is happy in 10' waves with GAMsides and G3000 trailor.. if its small/mushy ive used a G1000 or even a tiny GX trailer to really get loose...

I have yet to ride a Full set and really be happy with it...(occys, GAMs, some future foils.)

Huntington State · Post by **Huntington State** » Tue May 18, 2010 10:00 am

Skansand,
This is exactly the info I'm looking for......Thanks for the reply

skansand · Post by **skansand** » Tue May 18, 2010 1:00 pm

no prob, forgot to mention those tri fins are set @ 17 1/2" from the tail...

my new board will be around 5'11 x 25" and the fins(quad) are going to be set @ 16 1/2"....Hope it works like ive dreamed....

Mike Fernandez · Post by **Mike Fernandez** » Wed May 19, 2010 6:12 pm

How do you keep a 25" board on the rails in a bottom turn?

analbirth · Post by **analbirth** » Wed May 19, 2010 11:38 pm

more boat than board,