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  1. #1
    Senior Member chrispavlo's Avatar
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    No toe-in and centre fins !!!! OMG no wonder it has no drive

    finally a thread about toe-in and profiles of sidefins!!

    **************************************************
    this thread is solely about front/sidefins!!!
    in surf terms centre fin = symmetrical fin
    all surfboard/SUP sidefins are in fact asymmetrical.
    other as the title may suggest it both covers boards with
    center backfins (trifin/thruster) and with twin backfins (quad)

    most importantly it is a non-marketing/non-sales thread!!!
    it can be somewhat technical and difficult to read for some
    critique is allowed and will (hopefully) be openly discussed
    facts, experiences and physics behind the marketing curtain
    also ideas, analogies and birds eye perspectives are welcome!
    **************************************************




    there seem to be some 2010 trifins on the market, featuring
    symmetrical sidefins with no or just very slight toe-in angle,
    and i wonder if they perform at the level a trifin should?

    secondly, most of the 2010 quadfins / twinzers also have
    symmetrical sidefins with appearently no or almost no toe-in either..

    surfboards work very well with asymmetrical sidefins
    (inside flat, concave pocket or 80/20 profile)
    even in big waves and at high speeds!

    -----------------------------------------------------------------------------
    why is it so different in the current multifin windsurf boards???
    -----------------------------------------------------------------------------


    here a little example of a homemade surfboard, where the 'shaper'
    forgot the toe-in and wanted to cheat by using bigger sym fins:

    "Super floaty but its lacking drive...any ideas on how to gain drive?"
    ....
    "the fins have no toe, or cant. they are just flat. look like all three are center fins"
    "No toe in or cant and 3 centre fins !!!! OMG no wonder it has no drive..."

    -> http://www.surfing-waves.com/forum/v...p?f=14&t=15298



    just curious... any ideas, experiences???

    ;-) chris
    Last edited by chrispavlo; 26th August 2010 at 11:05 PM. Reason: comment

  2. #2
    Re-Fresh
    Guest
    Looks like a 10' longboard in which case i probably won't like a quad set up.

    Use the 2+1, big long boards need bigger centre fins!

  3. #3
    Senior Member chrispavlo's Avatar
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    Quote Originally Posted by Re-Fresh View Post
    Looks like a 10' longboard in which case i probably won't like a quad set up.
    that pic was just an example what is 'state-of-the-art'
    with SUPs in our days!

    there are both 2+1 and quad setups and the common part
    are the toed-in sidefins that seem to work well with them..
    -> http://blog.surfingsports.com
    Last edited by chrispavlo; 23rd July 2010 at 06:06 PM. Reason: typo

  4. #4
    Re-Fresh
    Guest
    OK, then the answer is simple (not that I'm sure wot the Q was)

    DON'T TAKE UP SUP!!

  5. #5
    Senior Member Jeroensurf's Avatar
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    I do SUP (had an few awesome sessions on it today) and another state of the art board
    Coreban9.6, wich is pretty much a shortboardstyle SUP and has a trifin setup. The 10.0 shown on the picture is a longboardstyle SUP but turns like a shortboard when pushed hard.
    My best friend:


    It got plenty of toe in but i can see a few reasons why a windsurfboard needs less to none:
    1: no matter how fast you paddle or surf on a wave, a windsurfer is entering a wave a lot faster and riding too. Having more momentum you need less lift to keep drive as a Surfer/SUP
    2) surfers/ sups have no straps; I don,t know how you guys bottomturn but in big waves i,m really hanging in my straps to turn the board with my backfoot in the strap almost without any presure on it. So i presume a sUP/Surfboard needs more help to turn the board = toe in.
    3) altough windsurfers also ride waves we are often further away from the wave as you can on any surfboard/sup. This makes surfboards/sups riding under a whole different ange as a windsurfboard. I don,t know but it might have some influence too. (only few persons who doesnt count this for are the guys alike Kauli, Josh etc)

  6. #6
    Senior Member Witchcraft's Avatar
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    Sidefins on a trifin or quad definately need toe-in. Ideally any new shape and fin set up should be tested with the 4wfs first to determine the best toe-in angle before being put into production. When you start with more extreme angles (0 and 3 angle) you can even clearly see a trail through the water behind the board, caused by excessive drag, from either the up wind or down wind fin and from there you start narrowing down which angles work best. We have been doing this since 2005 and (as regular followers of the various fin threads will know) these findings were published in 2007 in various magazines.....
    Bouke
    Witchcraft Windsurfing Fuerteventura

  7. #7
    Senior Member chrispavlo's Avatar
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    my own experiments with toe-in on different boards (v and concave bottoms)
    showed that on my boards i 'need' a lot of toe-in, even with sym fins.

    last session i played with a 6.6cm wake-style slim 60/40 frontfin
    and it was fast with an angle up to 2.0 degrees, while at 1.5 i had
    this white lines behind!

    my 9.7cm 90/10 profiled sidefins work best with exactly 2.0
    and my 12.5cm inside flat / outside s-curve fins performed best
    with an angle of 2.5 degrees (on the v bottom proof board)

    a flatter angle of just 1.1 degrees also worked well in jibes
    with smaller sym fins on my drops 4-traxx fsw board,
    although i didn't have enough wind to verify downwind highspeeds.

    so, there seems to be a range and multiple factors involved, not easy..

    this 4wfs would be a great help to find the right angles.
    at the moment i just sand my mt fin base and add 5-min epoxy material
    to adjust the angle between several micro sessions


    windy weekend is coming..
    Last edited by chrispavlo; 23rd July 2010 at 11:47 PM. Reason: typo

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