"Flatbottom" hull design efficiency

Discussion in 'Powerboats' started by Blackhawk30, Aug 24, 2011.

  1. Blackhawk30
    Joined: Aug 2011
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    Blackhawk30 New Member

    Concerning small (15'-20') recreational powerboats, I'm interested in feedback on the relative merits of the flatbottom hull design (e.g., the v-drive boats built by Sanger, Rayson-Craft, Cole, and a host of others during the 60's and 70's) vs. other hull types (deep-V, tri-hull, etc.).

    These v-drive flatbottom boats were typically powered by high-horsepower engines and driven to high speeds but I'm interested in the other end of the spectrum. How efficient, relative to other hull types, would you expect the flatbottom design to be in getting on-plane and maintaining moderate speeds with a low-horsepower engine?

    Any thoughts?
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The flat bottom hull form is the most efficient at getting up and staying on plane with the least amount of power. The discussion about different hull form types is quite extensive, so maybe it would be best to refine your questions a bit.
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    Depends on the waters it is to be used in, any kind of chop will see your kidneys being relocated nearer to your shoulder blades, or dental fillings loosened, in a flat bottomed planing hull.
     
  4. Blackhawk30
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    Blackhawk30 New Member

    "The flat bottom hull form is the most efficient at getting up and staying on plane with the least amount of power."

    Actually, that statement goes a long way toward answering my question. Thanks.

    I'm not sure this is refining the question, but just to view it from another angle in case there are more opinions out there ---

    --- If all you have available, for example, is a 50HP engine, and you want to get the most overall "performance" (best hole-shot, highest top speed, lowest fuel consumption at top speed, etc.) out of a 16' powerboat, what hull type would you choose: flatbottom? deep-V?; tri-hull?; tunnel-hull; other?

    Assume attributes such as ride quality, cabin configuration, cost, aesthetics, etc., do not matter. The concern is only efficiency in this exercise.

    Does this make sense? Any more thoughts?

    Thanks.
     
  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    . . .
     
  6. tunnels

    tunnels Previous Member

    If all things dont mater flat would be most peoples choice but Tunnels would be my choice !! They can and will fly so eliminating much contact with the surface of the water and skin friction keeping it to its minimum so in reality should go faster and give a ride on a cushion of air effect !!.
    In a chop here is no better than a tunnel boat and can be a really soft ride !!:p
     

  7. Yellowjacket
    Joined: May 2009
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    Yellowjacket Senior Member

    As Par noted, it depends on what you are trying to do and you probably need to more clearly define what the objective of the boat is.

    If the objective is to put a heavily laden hull on a plane, then a flat bottom is the best way to do that. If the objective is to take one person to near 100 mph on 50 hp, then a tunnel or a hydroplane or a design that rides mostly on air is what you need. If you want to carry two people at 60 mph and ride through some chop you might be better off with a padded V.

    There are so many different missions, that you have to define what you want to do with the boat before you can point to the best solution for that mission.
     
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