Hull speed

Discussion in 'Boat Design' started by Mike D, Jan 7, 2003.

  1. gonzo
    Joined: Aug 2002
    Posts: 13,786
    Likes: 436, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The tunnels also cause loss of lift and more turbulence. I think that the only real advantage is less draft.
     
  2. Perm Stress
    Joined: Sep 2009
    Posts: 554
    Likes: 23, Points: 0, Legacy Rep: 323
    Location: Lithuania

    Perm Stress Senior Member

    It is certainly two sided process: something you win, something you lose.
    Properly designed tunnels do not cause turbulence, by the way.


    The break point could be the required amount of lift -the deeper in pure planing area you are, the more important the lift becomes.
     
  3. PCVdominica
    Joined: Feb 2011
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Dominica

    PCVdominica New Member

    @ Perm Stress: The equation you posted ~10-13kW/t, does t=ton(s)? Does that equation have a name?

    Thanks for your response to my above questions =)
     
  4. Perm Stress
    Joined: Sep 2009
    Posts: 554
    Likes: 23, Points: 0, Legacy Rep: 323
    Location: Lithuania

    Perm Stress Senior Member

    Yes, t mean tons.
    The equation has no name really.
    A while ago I did statistical analysis of published data for various motor yachts; comparison between installed power and Froude number, based on quoted max speed was made.
    It was necessary to decide on ballpark figures for speed and power of large motor yacht design.
    At limit semi-planing/planing there was 10-13kW installed power per ton of quoted full displacement. That's all.
    P.S.
    all the data used for analysis as published:
    published max displacement
    nominal power of engines
     
    Last edited: Feb 27, 2011

  5. jwitzel
    Joined: Jun 2013
    Posts: 1
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Ft. Lauderdale, FL

    jwitzel New Member

    Spreadsheet question

    I have a question about the spreadsheet Mike D. submitted a few years ago; what function does the single/twin engine input provide? It seems as though the internal equations are for single engine applications only. Am I wrong?



     
    Last edited: Jun 29, 2013
Loading...
Similar Threads
  1. Doh
    Replies:
    59
    Views:
    2,956
  2. johnnythefish
    Replies:
    34
    Views:
    4,532
  3. Trixini
    Replies:
    9
    Views:
    1,698
  4. Phil Christieso
    Replies:
    36
    Views:
    3,793
  5. Jon E
    Replies:
    68
    Views:
    12,352
  6. devudegoa
    Replies:
    2
    Views:
    1,625
  7. Beachside485
    Replies:
    0
    Views:
    1,036
  8. nqb12179
    Replies:
    35
    Views:
    3,989
  9. William George
    Replies:
    29
    Views:
    9,889
  10. Dhutch
    Replies:
    24
    Views:
    12,619
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.