planning hull running surface

Discussion in 'Powerboats' started by gtflash, Sep 22, 2013.

  1. gtflash
    Joined: Jun 2006
    Posts: 128
    Likes: 0, Points: 16, Legacy Rep: 10
    Location: uk

    gtflash Senior Member

    How much wetted area does a planning boat hull run on when at speed?

    Bit of an open ended question, but i have spent ages looking at youtube videos, of racing boats and im still undecided. Id guess at less than 1/3
     
  2. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,386
    Likes: 1,042, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    1/3 of what, the below chine area ? The below static waterline area ? Depends on a number of things, principally the speed, weight of boat, hull shape, trim angle etc. Why do you want to quantify this ?
     
  3. Olav
    Joined: Dec 2003
    Posts: 334
    Likes: 50, Points: 38, Legacy Rep: 460
    Location: Filia pulchra Lubecæ

    Olav naval architect

    gtflash,

    you might want to get familiar with Savitsky's 1964 method for estimating the running attitude (trim, rise) and resistance of a prismatic planing hull. There are also several approaches to include non-prismatic (warped) hulls as well.

    A member of this forum (Dingo) did a superb job and made an Excel spreadsheet which you can download here.
     

  4. gtflash
    Joined: Jun 2006
    Posts: 128
    Likes: 0, Points: 16, Legacy Rep: 10
    Location: uk

    gtflash Senior Member

    Thanks Olav, I will research more on that.

    Mr efficiency, I was thinking high speed craft, +70mph. I kind of decided in my head that at lesser speeds, hull sizes and weight would create different resolutions, however over a certain speed all hulls would be balancing on an equally small surface as a % of running surface. Yet watching videos it didnt appear i was right
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.