resistance of a vessel

Discussion in 'Hydrodynamics and Aerodynamics' started by naupigos_gr, May 4, 2012.

  1. naupigos_gr
    Joined: Feb 2009
    Posts: 45
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    naupigos_gr Junior Member

    Generally speaking lets say a pnmx with bulbous bow does it have less resistance than the same pnmx without bulbous bow design. As a result needs less effective power to move a the same service speed?

    thanks and best regards

    John
     
  2. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Bulbs are very sensitive to speed and displacement, so at ONE speed above a Fn UNIQUE to the hull form, and ONE draft for the hull form, yes, a bulb would need less effective Hp to move at THAT speed. This is why route ships and things like cruise liners use them and other ships do not. See the following threads.

    http://www.boatdesign.net/forums/boat-design/bulbous-bow-design-18043.html
    http://www.boatdesign.net/forums/boat-design/bulb-quest-again-12004.html
    http://www.boatdesign.net/forums/boat-design/forward-torpedo-tube-ships-34004.html
     
    1 person likes this.
  3. naupigos_gr
    Joined: Feb 2009
    Posts: 45
    Likes: 1, Points: 0, Legacy Rep: 9
    Location: N/A

    naupigos_gr Junior Member

    Hi jehardiman,

    thanks for your reply.
    you know I'm just evaluating some results from hullform and I got confused !
     
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