Nacra 20 / Nacra F20 hull drawings or CAD

Discussion in 'Boat Design' started by rolfknudsen, Jan 23, 2013.

  1. rolfknudsen
    Joined: Jan 2013
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    rolfknudsen New Member


    I am new here as a member, but have been following the great depth of knowledge here for a while!

    I am interested in knowing a bit more about the design philosophy behind the hulls on the Nacra F20 Morelli and Melvin Catamaran Design.

    1. Do you know of any plans or maybe even CAD available for download somewhere so I can study this in more detail? I of course understand it might be asking for something that is a business secret so-to-speak, but have no intention of violating anyone's IP - all I want is to learn a bit more by having the real material at hand. I have a hard time following the theoretical side of boat design....

    If not - is there any other plans available possibly with a design statement accompanying these?

    2. In broad terms - is a hull scalable i.e could the 20' F20 hull be scaled directly to a F30 for example or are these two completely different beasts (weight/loads not proportionally scalable?).

    Thank you,

  2. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    I assume you have already asked M and M direct?

    usually people use a bigger boat in different sea states than a smaller one, which means the boats are totally different

    But if, for example, you want to race inshore on short courses round the buoys then yes you could probably scale up. The old F40 class was a Tornado doubled (in concept at least, the hull shapes were all very different)

    length varies by the scale factor, area by the factor squared and displacement by the factor cubed. So bigger boats are more stable than smaller ones. But crew weight is less of a factor on a bigger boat, and crew strength doesn't increase with length

    Richard Woods of Woods Designs
  3. rolfknudsen
    Joined: Jan 2013
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    rolfknudsen New Member

    Thank you very much for you quick response, Richard.

    No I haven't been in touch with M & M directly - this I will do. You quick guide to the basic maths for scaling up a hull is much helpful and greatly appreciated. Thank you for taking the time.
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