Any ideas how to improve resistance of such hull...

Discussion in 'Hydrodynamics and Aerodynamics' started by Alexanov, Feb 7, 2020.

  1. Alexanov
    Joined: Feb 2003
    Posts: 157
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    Location: Norway Sola

    Alexanov Senior Member

    Ship particulars
    Lpp 38.7 m
    Loa 39.9 m
    B 7.83 m
    D 2.6 m
    Load condition1
    T1 1.3 m
    m1 232.61302 t
    V1 8.1 kt
    Fr1 0.214
     
  2. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    It Seems an overloaded boat. Bow wave is big. May be a bulbos now?
     
  3. Alexanov
    Joined: Feb 2003
    Posts: 157
    Likes: 11, Points: 28, Legacy Rep: 10
    Location: Norway Sola

    Alexanov Senior Member

    Looks like parallel midbody is too long. There is a lot if negative pressure at bottom in foreship. That why it sink to foreship. It is a boat for lake. I am not sure about bulb... ideally it required as low as possible resistance, but I am afraid it is totally wrong shape for that...
     
  4. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    I take it for granted that the shapes of the ship cannot be changed neither the block coefficient or the prismatic, or the angle of entry at the bow and, since, imo, the bow wave is very large, I think a bulbous bow would reduce it, reducing resistance to wave formation.
     
  5. Ad Hoc
    Joined: Oct 2008
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    Location: Japan

    Ad Hoc Naval Architect

    The bow is too bluff.
    You need to reduce the angle of entry.
     
  6. Alexanov
    Joined: Feb 2003
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    Location: Norway Sola

    Alexanov Senior Member

    Thanks. I think you are right. Will try to change angle, if designer will agree.
     

  7. Alexanov
    Joined: Feb 2003
    Posts: 157
    Likes: 11, Points: 28, Legacy Rep: 10
    Location: Norway Sola

    Alexanov Senior Member

    Finally we remove knuckles and it helps a lot....
     
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