Fish Foil

Discussion in 'Surfboards and Surfboard Design' started by ClemsonSurf, Jul 8, 2014.

  1. ClemsonSurf

    ClemsonSurf Well-Known Member

    Dec 10, 2007
    Bo's and Doodbrahs,

    I've been thinking about the foils of a fish for a while, specifically the foil of the tail/cut away area. I get the outside rail foil idea and that the cut away is supposed to allow for more hold in the wave, so does the inside foil matter? I imagine it would be different if the board was concave vs. V'd.

    I can't quite wrap my head around it and have never surfed a true fish so I can't make a good judgement. Part of me is saying a hard turned down rail would work better the other is saying 50/50 might work better.

    *** I'm aware this is splitting hairs, I'm stuck in a hotel again without a rental and you'd be amazed how boring Mobile, Alabama is after dark.
     
  2. EmassSpicoli

    EmassSpicoli Well-Known Member

    Apr 16, 2013
    Looking forward to LBCrew and others to respond to this tread.

    btw, Clemmy, if you do get transport and have a night or two to get towards Floribama, let's talk.
     

  3. ClemsonSurf

    ClemsonSurf Well-Known Member

    Dec 10, 2007
    I'll let you know. Chances are slim.



    For everyone else. The title reads fish foil, not fish oil. I think we hashed out that conversation pretty well last year.
     
  4. EmassSpicoli

    EmassSpicoli Well-Known Member

    Apr 16, 2013
    Hahahaha didn't even think of that! That tread sucked bro. You just saved brewengineer 152 posts from clarifying. This one will be much better.
     
  5. Agabinet

    Agabinet Well-Known Member

    309
    May 3, 2012
    I have an asymmetric fish shaped by Rick Malwitz in Jersey, and the inside foil of the tail is definitely turned down hard. No 50-50. The frontside tail is a concave and the backside tail is a spiral vee, both outer rails are hard at the tail. The board does go and turns quick in soft RI surf.
     
  6. ClemsonSurf

    ClemsonSurf Well-Known Member

    Dec 10, 2007
    Bump for the non-nocturnal crowd.
     
  7. LBCrew

    LBCrew Well-Known Member

    Aug 12, 2009
    The theory is that the inside of the cutout of a true fish tail is all about the combination of hold and release. Seems like an impossibility, but think of it this way... when you put the board on a rail, you want the buried inside lobe of the fish tail to act like a fin, adding fin-like projection out of the turn. Following that concept of tail lobe-as-fin, you want the trailing edge of a fin to release water cleanly. The inside rail of the lobe of the tail becomes the trailing edge of the fin. In order for water to release cleanly, you want a thin, down rail, with a hard edge. You don't want any water wrapping around the inside rail of the fish tail, because that creates suction and drag (coanda effect). Also like a fin, the outside rail of the lobe of the tail is rounder and softer than the trailing edge. Between both rails, the lobe itself is slightly foiled, just like a fin. Below is a pic of the hard, down, inside rail.
     

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    Last edited: Jul 8, 2014
  8. LBCrew

    LBCrew Well-Known Member

    Aug 12, 2009
    compare that to an outside rail...
    IMG_3009.jpg
     
    Last edited: Jul 8, 2014
  9. ClemsonSurf

    ClemsonSurf Well-Known Member

    Dec 10, 2007
    It took a couple re-reads and the second picture pulled it together.


    "So much knowledge in the LBC"
    -Snoop Dogg