Tell Me What These Fins Will Do On My Mandala

Discussion in 'Surfing' started by Killafornia, Jul 8, 2018.

  1. Chilly Willy

    Chilly Willy Well-Known Member

    Feb 15, 2004
    USA New Jersey
    I'm not a fin expert, but I'll take a crack at it. My guess is that the blue one (not the Turbo Tunnel) will slow down the cutbacks for you. Bigger base, not as loose, longer radius turns, more drive. Probably also that funky fin being that it has the bigger base and a lot of rake. (If you try it, post up your report! Reminds me of the hotels in Wildwood, NJ. If nothing else, it'll be a conversation starter.) Everything else looks like a narrower base, so looser turns.
    Killafornia likes this.
  2. Killafornia

    Killafornia Active Member

    Oct 1, 2009
    Wider base, ok I will give those two an honest trial.
    I rode the board again yesterday and fuck it's fun.
    I might have just found my two board quiver. I see some nice boards comming up on the chopping block soon.
  3. JBorbone

    JBorbone Well-Known Member

    Oct 18, 2017
    Belmar, NJ
    pretty tough to tell how the fin will react given the pictures.

    Just as important as the rake, height, and base width (mentioned previously in the thread) are the foil attributes like the leading edge, the spine height, the spine location, and the material used. blunt leading edge vs thin leading edge will have a dramatic change on drive vs turnability. spine being further forward will provide less torsion flex and more directional flex. if the spine ends lower on the fin then the tip will have much more flex. thicker foil throughout will provide more drag.
    Killafornia likes this.
  4. shadydave

    shadydave Well-Known Member

    Mar 10, 2014
    Ayer Ma USA
    This is why I prefer fins that are glassed in. :confused:
  5. Chilly Willy

    Chilly Willy Well-Known Member

    Feb 15, 2004
    USA New Jersey
    What's the spine? I don't think I've ever heard of that in relation to fins. As far as blunt vs. thin leading edge, which one does what?
    JBorbone likes this.
  6. JBorbone

    JBorbone Well-Known Member

    Oct 18, 2017
    Belmar, NJ
    the spine is the widest point of the fin, associated with the thickest foil point. the location of this thickest point will determine which part of the fin has the most flex because it'll usually be on the opposing side of the fin (because it'll be the thinner area). This also indirectly changes the LE (leading edge) characteristics because it's difficult to hand-foil a fin to have a very narrow leading edge that also has a spine thats very far forward.

    for LE reference, you can see the coefficients below. wider leading edge GENERALLY (not always) means more drag, predictability, and directional turn ability. whereas a narrower LE will mean more drive and down the line speed.

    fins can also have biaxial foil, where water is not only meant to change direction from front of fin to back of fin, but also from base of fin to tip of fin. Very few fins have biaxial foil, but they do exist.

    applekat and Chilly Willy like this.
  7. ekim

    ekim Active Member

    Oct 14, 2015
    You have too many fins. Keep The A flex, sell all the rest and buy a 9" 4A . What do I know though?
  8. Left Coast 46

    Left Coast 46 Active Member

    Apr 30, 2015
    So Cal
    I’m a firm believer of. The A flex!! They make bad boards good boards.
  9. Malibootay

    Malibootay Member

    Sep 13, 2017
    Newport/West Hills
    I have a similar board (in 9'3") and ride a 9.75 4a style fin and im about to put a CC tracker 8.5" in because the fin has just felt way to big and draggy. Wide base did help with speed as I pumped along I feel. I would just take everyones suggestion and get a 9" 4a or an A flex.

    I like my fin all the way forward on shapes like this. Too far back has less pivot point I feel, so maybe pushing your fin to the back of the box will help slow cutbacks, but will loose some drive.
  10. nedsurf

    nedsurf Well-Known Member

    Jan 22, 2005
    Looks like the fin is all the way forward. Before changing fins I'd just move it to the back of the box, see if that helps

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