Small 2 seat speed boat

Discussion in 'Boat Design' started by loudandfast, Sep 6, 2023.

  1. loudandfast
    Joined: Sep 2023
    Posts: 3
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    Location: North West Montana

    loudandfast New Member

    Hey everyone, I'm pretty new to building boats. I built a small hydroplane when I was young and I also helped a friend build a minimax. Now I'm wanting to build another one this winter. I want a smallish boat (somewhere in the neighborhood of 14 feet) that can carry 2 adults and would be good for 60+ MPH. I would like to do some sort of an inboard engine ( probably a PWC engine between 80 and 150HP) and a homebuilt surface drive. What models do you recommend? Should I be thinking hydroplane or vee? The river I'll be using it on is smooth except for the occasional wake boat coming by, so it'll need to be able to handle that. I like the idea of the clarkcraft 14ft tunnel but it wouldn't work with an inboard. I like the looks of the clarkcraft airborne 11 but of course it's not big enough. Maybe it's possible to scale it up? Thanks!
     
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    The so called "surface drives" are really only one way to run a ventilated propeller. You can do the same with an outboard at less cost, weight and complication. Your target speed makes the design critical. Small mistakes in design and construction that would be irrelevant at 20 mph will be deadly at 60+. I recommend you find an existing design and preferably get help from an experienced boat builder. If speed and two occupants are constraints, then the type of hull, engine and drive will be determined by them.
     
  3. loudandfast
    Joined: Sep 2023
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    Location: North West Montana

    loudandfast New Member

    Thanks for your reply! I agree with everything you said except the weight thing. I fully believe I could do a PWC engine and a home built surface drive way lighter than an outboard motor. At least if we're talking in the 150HP range. Now if we're talking 80HP I'm not sure. Not familiar with the weight of that size outboard. And cost wise I already own a collection of PWC engines to chose from so that's one reason I want to go that route. I agree with you on going with an existing design, I was hoping someone could point me to one I hadn't found yet because I haven't found one that's ideal.
     
  4. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Why are you set on a surface drive when you have factory designed and built jet drives?
     
  5. loudandfast
    Joined: Sep 2023
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    Location: North West Montana

    loudandfast New Member

    Mainly because of efficiency... I'd probably have a top speed of 45-50 and drink 10 gallons of fuel every hour or two if I were to use one of the jet drives.
     
  6. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

  7. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    A 150HP engine will use about 13 gallons/hr.
     
  8. DogCavalry
    Joined: Sep 2019
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    Location: Vancouver bc

    DogCavalry Senior Member

    A boat like that isn't really something you worry too much about fuel consumption in. But an outboard run in surface piercing mode is a great compromise. Definitely massive improvement in mileage over a jet drive.

    @sandhammaren05 is an expert in this field, and has posted many highly informative posts over the years.
     

  9. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . _ _ _ . . . _ _ _

    For the sexy rooster tail of course! :)
     
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