Formula to calc HP requirements of pontoon

Discussion in 'Propulsion' started by rduval, Sep 29, 2005.

  1. rduval
    Joined: Sep 2005
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    Location: Toronto, Ontario, Canada.

    rduval New Member

    Hi:

    I'm a layman and have been tearing my hair out with various formulas...

    Can someone either point me to some formulas or software or tell me the HP required to propel a vessel on a pair 40ft x 2ft diameter round pontoons (50% submerged) at hull speed, 10 knots, 15, knots, 20 & 25 (I know there's a lot of factors but just approximately)?

    I have a 40ft houseboat that does 5.5kn with a 120hp engine. I want to get more speed but I'm knot sure how much HP I will ahve to throw at it to achieve reasonable increases.

    Thanks much in advance for any help

    Rick
     
  2. Jango
    Joined: Aug 2005
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    Location: Mid Atlantic

    Jango Senior Enthusiast

    HP with respect to speed is exponential, if nothing else changes. Twice the Speed requires 4 times the power. A 50% increase requires 1.5 squared or 2 1/4 the power etc.
    Hope this helps, Jango
     
  3. george allard
    Joined: Jul 2005
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    Location: kentucky

    george allard Junior Member


  4. Ike
    Joined: Apr 2006
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    Location: Washington

    Ike Senior Member

    HP = volume of the pontoons in cubic feet X the pontoon length in feet / pontoon diameter in inches
     
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