Pointers about my 6.7m sailing boat design (total noob)

Discussion in 'Boat Design' started by ArchiSail, Mar 21, 2020.

  1. ArchiSail
    Joined: Nov 2019
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    ArchiSail Junior Member

    Hi, im a noob in sailboat design.

    Anyways heres a concept for a 6.7m (22ft) sailboat.

    Some things i have questions about:

    first off, the totally flar hull, how will it effect sailing? i know flatter hull boats usually are faster, but currently this is completley flat.

    Secondly, the general geometry, how is it? is there anything i should change?

    the boat looks a bith chunky, but thats intnetional, to create as much interior volume as possible.

    lastlty, this boat is designed in Inventor(autodesk) and i'd like to open it in delftship, however i cant fint a file format that defltship supports. can anybody help me with that? anotherviewidonthavetheenergytocomeupwithname.png
     

    Attached Files:

  2. gonzo
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    gonzo Senior Member

    To begin, a design starts with a statement of requirements (SOR). This is a list of what a boat needs to accomplish and what you wish it can have. For example, speed, accomodation size, aesthetics, etc. Then, add the constraints. These are crucial because they limit the design. They include maximum dimensions, materials, regulations, etc. Drawings will be a representation of the design. They are not necessary but make visualizing it easier.
     
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  3. bajansailor
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    bajansailor Marine Surveyor

    +1 re Gonzo's comments above.
    Archi, you appear to be trying to re-invent the wheel here.
    Is this boat the development of your ideas in your previous post back in November?
    6.5m planing hull sailboat. All tech info/tips appreciated. https://www.boatdesign.net/threads/6-5m-planing-hull-sailboat-all-tech-info-tips-appreciated.63118/

    Your best bet, if you really want a boat of this size / shape, is to look at the Mini-Transat boats for inspiration. They have done all the 'hard work' for you already.
    If your ideas (as shown in the sketches above) were practical / better, the Mini research would have gone that route.
     
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  4. gonzo
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    gonzo Senior Member

    The Minis are great boats. I prefer the older designs that were not as specialized for downwind sailing.
     
  5. ArchiSail
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    ArchiSail Junior Member

    Bajansailor, i think you misinterpreted my post. im not trying to reinvent anything. Its just a idea for a 6.7m sailingboat with alot of livingspace. Im not trying to make a raceboat. Furthermore, i dont really understand both Gonzo´s and your commetns. Not that they're wrong or anything, i just don't understand what you guys are saying. You need to keep in mind that im copletley oblivious in the world of boatdesign.

    Mostly want to know how the flat bottom will effect sailin
     
  6. bajansailor
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    bajansailor Marine Surveyor

    Well, everything in boat design is always a compromise - I think that with that hull shape you have drawn will have to try to sail her as upright as possible. Because when she heels even slightly the shape of the heeled waterline will be very 'unbalanced' fore and aft which will probably play havoc with her handling (especially so if she only has a single rudder, instead of twin rudders).
    And then she will be much more inclined to 'spin out' or 'round up'.
    And in anything more than a sea state with small waves she will probably pound terribly when she 'falls off' a wave when going to windward.
    This is one reason why it is nice to have some 'vee' shape in the hull.

    You mention that you want a lot (relatively) of living space - is this mainly down below, or in the cockpit as well? How many people will you be taking sailing on her on day sails, and also on overnight trips?
    If the cockpit does not absolutely need to be so large you could reduce the beam at the stern without really affecting the amount of accommodation down below, and your waterlines would also then be better balanced (?) .
     
  7. clmanges
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    clmanges Senior Member

    Won't that flat transom suck the thing backwards?
     
  8. ArchiSail
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    ArchiSail Junior Member

    Thanks mate, that's exactly what I wanted to hear.

    Will round off the bottom, don't want to capsize haha.
    I don't want storage under the cockpit accessible from the cabin, that will be reachable from the cockpit.

    I really like a big cockpit, but cabin space is priority, although I'm satisfied with both cabinspace and cockpit.

    Two people overnight, maybe four day sail. Overnight is priority over daysailing, hence the toiletroom.

    Anyways, great comment, really appreciated. Have a great weekend!
     
  9. ArchiSail
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    ArchiSail Junior Member

    I mean, most competition sailboats have flat transom?
     
  10. bajansailor
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    bajansailor Marine Surveyor

  11. ArchiSail
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    ArchiSail Junior Member

    Stretched in witch direction?

    She's already 3m wide so she'll be mighty fat if u stretch her more
     
  12. bajansailor
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    bajansailor Marine Surveyor

    Stretch the Red Fox by 0.5 m. length wise - and then she will be the same length as your design.
     
  13. ArchiSail
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    ArchiSail Junior Member

    Great reference!!
     
  14. ArchiSail
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    ArchiSail Junior Member

    Aha!
     

  15. gonzo
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    gonzo Senior Member

    What we are saying is that a drawing is not a design. A design is a creation that satisfies a set of parameters and requirements. You need to start by stating what those are. If you need to learn how flat bottom boats sail, do not draw a hull; read about boat performance. Flat bottom boats need to be narrow to sail moderately well. That is the opposite to your constraint of large interior volume.
     
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