New design a 22m motor boat - first shape of hull

Discussion in 'Boat Design' started by micspoko, Jan 4, 2012.

  1. PAR
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    PAR Yacht Designer/Builder

    I was under the same impression Alik, which is why I jumped all over him too. It just goes to show how easily verbiage can justify or qualify a post. This poster has run into this issue previously, if my memory serves me.
     
  2. daiquiri
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    daiquiri Engineering and Design

    You have not corrected the main issue with this hull, which me and others have been pointing to - the curved buttocks:
    lines plan 2.jpg

    You need straight buttocks down there, or else you'll be creating a tremendous drag at high speeds. Your hull is roughly equivalent to a displacement hull with built-in planing tabs, conceptually similar to the ones seen in this thread: http://www.boatdesign.net/forums/boat-design/semi-displacement-33509-2.html#post378957 . It might even plane if sufficiently lightly built, but it will do it in an inefficient way - consuming a lots of fuel and pointing the bow upwards.

    So, this is the first modification that you need to do:
    lines plan 3.jpg
     
  3. PAR
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    PAR Yacht Designer/Builder

    I think the first thing that should be done is considerably more study into the basics of powerboat hydrodynamics, particularly planing hulls.
     
  4. micspoko
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    micspoko Senior Member

    I think I will stay with this hull but a lower a max speed for this boat to 20 kn
     
  5. Leo Lazauskas
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    Leo Lazauskas Senior Member

    And just to confuse the issue more, in ship hydrodynamics, the hull often points
    to the left: the hull is assumed to be stationary, and the fluid flows from left to
    right.
    Some hydronuts point the bow to the right, but we mock them.
     
  6. daiquiri
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    daiquiri Engineering and Design

    I couldn't agree more, PAR.
     
  7. PAR
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    PAR Yacht Designer/Builder

    You're dreaming at 20 Knots and if you don't know why, then my previous post (last) should sufficiently explain your next step. It's absolutely ridiculous, to explore a cave without a flashlight, don't you think? How about design a yacht without a clue on Hydrodynamics?
     
  8. micspoko
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    micspoko Senior Member

    New photo from work
     

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  9. FMS
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    FMS Senior Member

    From a 3D modeling standpoint, it looks good.

    The style is different. A 'displacement' hull under a 'faster looking' superstructure. I actually appreciate different. But it is perplexing too. What would be a chine of a planing boat is clear of the water in the render. Is it a styling line only to project the hull aft and out? And/or have you rendered it "sitting on a piece of glass" not representing the actual waterline?

    Disregarding the hull shape aft still, from a functional standpoint, you can't get to the bow. The narrow side decks and no access to them would make it difficult to get around in some situations. There is no exterior helm station option, and there isn't much outside deck space to enjoy - you are always looking through glass while boating.

    Is there a GA plan?
     
  10. micspoko
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    micspoko Senior Member

    Thank you for your opinion

    The actual look not respond to waterline. Draft will be larger then is on this pictures.

    I tired to design a superstructure so as not to spoil and this is the result

    On sides of superstructure is a 600mm deck to go around. I now it is small but enough to go to the bow

    I don`t have a GA

    Space on bow deck and rear deck - the style of this boat is like this
     
  11. daiquiri
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    daiquiri Engineering and Design

    Apart my previous critics about your hull shape, which are still valid because you did not change the critical issues, I do recognize that you have put a lots of efforts into this 3D model, and I praise you for that. While doing it, you have probably become pretty proficient with the software you've been using, which can always be useful for other future tasks... :)

    I would like to point one thing which might look ok on the computer screen but is not acceptable on a real boat - the double change of curvature (from concave to convex) of the front windows. Due to the refraction of light through transparent materials, it will create a weird and deformed view from the inside which, apart the aesthetics, will make the helmsman's job pretty difficult and eye-tiring. I would suggest to make a simply curved window panels, possibly flat or slightly convex, but definitely not concave.

    Cheers
     
  12. mydauphin
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    mydauphin Senior Member

    I would add a bathroom in salon. Many boats make you go downstairs to use them. Apart from that, I would add side walkways, a better transom and on a boat that big an upper exterior bridge.

    On windshields and glass in general, they can be made but they will cost a fortune.
     
  13. quequen
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    quequen Senior Member

    Nice renders micspoko, are you using Hypershot?
    I wish there was a thread about render tecnics, nautical materials etc. in this forum. Selling the boat is also part of the business, I think.
     
  14. micspoko
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    micspoko Senior Member

    A new month and a new pictures
     

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  15. daiquiri
    Joined: May 2004
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    daiquiri Engineering and Design

    What do you expect us to say, that hasn't already been said? I see all the previously mentioned flaws still there, so it is obvious that our words are not getting any of your attention. So, at this point, wish you a good luck.
     
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