Bilge Keels

Discussion in 'Boat Design' started by joeysranger, Sep 9, 2008.

  1. joeysranger
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    joeysranger Junior Member

    Need help designing bilge keels for 70ft X 20ft ferro-cement motorsailor. Boat is curently 8ft draft, would like to eliminate some draft if possible. Would like to know how to size keels for a given boat (L-B-D). Also keels might help with rolling (first mate dosen't like rolling).:eek: THANK YOU.
     
  2. brian eiland
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    brian eiland Senior Member

  3. joeysranger
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    joeysranger Junior Member

    I dont want twin keels i want bilge Keels
     
  4. rwatson
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    rwatson Senior Member

    and the difference bewteen bilge keels and twin keels is .......... ??
     
  5. alan white
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    alan white Senior Member

    You can reduce rolling by cutting off the bottom of your existing keel, losing some stability. Adding bilge keels is the same thing as rebuilding the entire boat from scratch---- it would probably be cheaper to build a whole new ferro hull and install the parts from the original into it. In other words, probably cheaper to build new.
    Appendages like bilge keels would require a great deal of reinforcement without the benefit of a contiguous steel frame--- somehow the keels would have to sandwich the hull between matched bolt-together steel plates at the keel root inside and out, and also new, deeper floors welded across to secure the inside plates, which would weld to the floors.
    But maybe someone has another idea.
    Sounds drastic... how about hoisting an anchor up the rig?

    Alan
     
  6. Jack Daniels Eq
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    Jack Daniels Eq Shockwave

    Lose ya growler
    BR>Jack
     
  7. joeysranger
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    joeysranger Junior Member

    A twin keel boat only has two keels. A bilge keel boat has a shallow center keel with a long fin on each side. Boat is not built yet, still in planning stage. Bilge keels not included in plans.
     
  8. TeddyDiver
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    TeddyDiver Gollywobbler

    A bilge keeler is a twin keeled boat.
    A center keel with a foil each side is a wing keel.
    A shallow center keel with along fin on each side is _______ (fill your suggestion):D
     
  9. joeysranger
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    joeysranger Junior Member

  10. joeysranger
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    joeysranger Junior Member

    Great you've never heard of it , so I guess it doesn't exist. Must have all been a dream. Darn I had such high hopes.:confused: :confused:
     
  11. tom28571
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    tom28571 Senior Member

    It exists all right. The problem is that not everybody agrees on the name and it is useless to assume that all know these keel forms by the same name. I, probably along with Brian and others use different terms than you for these keel configurations. Who is to be the ultimate arbitrator? Just forget it and explain what you mean so that there is no ambiguity.
     
  12. rwatson
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    rwatson Senior Member

    Build a catamaram like everyone else - monohulls will always roll unless you get some expensive gear installed like the car ferries
     
  13. joeysranger
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    joeysranger Junior Member

  14. rwatson
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    rwatson Senior Member

    NO NEED TO SHOUT!!! :)

    A bilge keel is a fin (or keel) attached to the bilges, whether there is a central fin (or keel) or not.

    Logically - a twin keels have to be on the bilges, or they wouldnt be twins.

    Instead of getting hung up in definitions, perhaps you could explain why the heck you think the extra drag of two extra keels would enhance the function of a boat. Why dont you just make the one keel longer with more weight to dampen roll ?

    or like the previous clever poster suggested, -build a catamaran.
     

  15. Jack Daniels Eq
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    Jack Daniels Eq Shockwave

    With your attitude & ya growlers' propensity to whine, this boat aint goin nowhere
    Keep it on the drawing board & inhale deeply
     
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