About inclined underwater hull form

Discussion in 'Hydrodynamics and Aerodynamics' started by fredschmidt, Feb 18, 2012.

  1. Mikko Brummer
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    Mikko Brummer Senior Member

    I quote myself in post 30...
     
  2. fredschmidt
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    fredschmidt Naval Architect

    Mikko,

    Certainly.

    Arriving at the conclusion that there is an interrelationship hull / keel in the production of lift, where the hull contributes effectively to the lift, my first thought upon discovering that chine cut heeled waterlines, turning them into asymmetrical foils, was the improvement seeking to make the waterlines so that, when heeled they have a shape of a foil somewhat better.
    Would like to know your opinion about how best to do the waterlines?
     
  3. fredschmidt
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    fredschmidt Naval Architect

    " When heeled, a well designed chine gives a sharp trailing edge to the canoe body foil making it, for the reasons just discussed, into a much more efficient lifting device producing greater circulation and thus lift and also, less drag. "

    Well, another people talking about canoe body foil and saying that chine heeled, turn the canoe body foil in a much better lifting device.

    Well, and some people do not see foils in water lines of the hull.

    Unfortunately the aero/hidrodynamic problem is a few complicated, and I understand that if the physical phenomenon is already quite complicated, imagine thinking in 3D.

    I hope that this thread it does not end by here.

    I hope new people will bring their thoughts because an idea brings another, as well as brain storm.

    A great difference of Einstein was that his lab was his head. He needed only logical, right, of course.

    So, before leaving for laboratory confirmation is necessary to make a theory.

    As truths are almost never entirely truths, you need to open your mind, assume new things. And I think it would be great if we could evolve in this direction.
     
  4. petethai
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    petethai Junior Member

  5. rowboat70
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    rowboat70 Junior Member

    The scow is a double-ended boat in profile, rather than in plan view,
    When the scow heels over, the waterlines develop well-balanced asymmetry.
    The scow's waterlines are so well balanced that it develops no weather helm when it heels over.
    The tiller is in the center of the boat until the mast hits the water.
    The efficiency of the scow is best demonstrated by comparing a 20-foot C scow to a 20-foot Flying Dutchman ("the world's fastest monohull"). The Portsmouth Yardstick shows nearly identical ratings for both boats. The 650-Lbs C scow is a catboat with a rotating mast and no head sails at all. The 375-Lbs Flying Dutchman is a sophisticated sloop with a genoa jib and a spinnaker. Currently-available scows leave lots of room for improvement in design, which would make scows even faster than they already are. The pram bow that smashes into the oncoming waves, the large-radius round bilge that offers minimum lateral resistance, and the topsides that curve in plan view, are all factors that can be improved upon.
     
  6. fredschmidt
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    fredschmidt Naval Architect

    Scow

    It would be interesting see the heeled water lines from Scow,
     
  7. CT 249
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    CT 249 Senior Member

    In the most popular International development class, the Moth, scow types were the subject of about 60 years of experimentation in at least five countries. Among the designers who drew Moths in this era were Bruce Farr, John Westell (of 505 fame), Frank Bethwaite IIRC, Finot, Claridge, Shelley (creator of the first successful chine Int 14), Randell (creator of the first successful Aussie 14), and many other top names.

    And none of them could create a scow Moth that would keep up with the conventionally-shaped boats after 1987. By the time Moths moved onto hydrofoils they had evolved into very skinny almost double-ended shapes with no chines and at just 11 feet long and with about 80 ft of sail, they could beat Dutchmen and would have beaten a C Scow.

    The scow Moths were enormously fun, as scows are. But they were about 15% slower than the skinny 'skiffs' that Moths evolved into. Scows have also been tried in other development classes and failed. Great boats, because of their feel and the combination of speed and stability. The fastest monos? Nope.
     
  8. rowboat70
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    rowboat70 Junior Member

    "none of them could create a scow that would keep up with the conventionally-shaped boats" proves that they did not understand the concept of the scow and how the scow works. They failed because they did not understand what they were trying to do. They were just going through the motions and hoping for the best. They put a pram bow on a conventional boat and called it a scow.
     

  9. rowboat70
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    rowboat70 Junior Member

    The Portsmouth Yardstick rating for a Moth is 107.
    The Portsmouth Yardstick rating for a C-Scow is 79.
    They're not even on the same planet.
     
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