DSS 49er

Discussion in 'Sailboats' started by revintage, Jan 12, 2019.

  1. revintage
    Joined: Nov 2016
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    revintage Junior Member

    Looked at the old 49er that we(two grumpy old men) are frankenboating this winter to a Sportboat, with 50kg bulb, carbon fibre fore deck and hiking wings. Like a smaller version of VX-One.

    Today we got the idea to do a Stage 2 mod with DSS style foils like Monofoil Gonet. Except for adding the foils the T-foil rudder probably needs to be moved a bit more to the rear.

    Below is some guesswork of how it could be done.

    IMG_3435.JPG 49dssfront4.png 49dssfront5.png Gonet monofoiler 30 knots.jpg franken9er.png
     
    Last edited: Jan 12, 2019
  2. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    The first thing I thought is, and apologize if the question is not very intelligent, would it be possible, or good, to eliminate the bulb keel?
     
  3. revintage
    Joined: Nov 2016
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    revintage Junior Member

    If you check a 49er as is, it is sailed by two athletes in trapeze on 60cm wings.

    It will now be sailed by two retired guys that have passed their best-before-date since long, with their behinds hiking out from 80cm wings.

    So a bulb will for sure be needed, to compensate for the lost righting arm. Actually a heavier bulb will be needed to make the two equal.

    Another reason for adding a bulb is that we then are allowed to participate in our clubs handicap races, no dinghies allowed.
     
  4. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    You might consider a "real" Welbourn foil that would be simpler and lighter . I imagine you have-or will- do the calculations to make sure the foil area you choose will work. The Quant 23 system designed by Hugh Welbourn also has the advantage of really light air takeoff. His Quant 23 was the first foiling keelboat ever....
    Good Luck-sounds like fun.

    Quant 23 foil illustration.jpg
     
  5. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    revintage quote:
    "A foil like that is out of the question due to the costs involved. My solution will do the same job. How do you think I found out the take off speeds without doing the math?
    The lifting foil will be parallell to water surface at 16% heel.
    Will use my straight foil section described in my Trifoiler thread. "
    ----------------------------

    You think one "Gonet" type foil(foil+2 "legs") will cost less than one Welbourn foil? I seriously doubt it. Hope it works out.
    What is your projected takeoff windspeed?
     
    Last edited: Jan 12, 2019

  6. revintage
    Joined: Nov 2016
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    Location: Sweden

    revintage Junior Member

    TANSL, it might be worth a try to use the original daggerboard(if it is long enough) in foiling mode, as the leeward foil ads righting moment by the lengthened righting arm. Have to do the math on that option.

    Will still keep the bulb for club races without hydrofoils.
     
    Last edited: Jan 13, 2019
    TANSL likes this.
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