looking for a well shaped catamaran hull

Discussion in 'Multihulls' started by smartcat, Mar 14, 2016.

  1. smartcat
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    smartcat Junior Member

    Hello, I am in progess with the Design for a trailable Catamaran with a length in waterline of 6,6 m and a displacemant of 1350 kg. I com near to the end with the hole design. It is generally built in plywood and multichine. But i am not satified with my own hullshape.
    So, here is my question and my hope. Do there exist some current linedrawings in CAD for that type of boat to compare them with mine?

    TX

    Michael
     
  2. gonzo
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    gonzo Senior Member

    Is the decimal point off? A HobieCat 18 weighs 182 kg, a NACRA slightly less. If the posted figure is correct, I assume it is a power cat.
     
  3. Richard Woods
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    Richard Woods Woods Designs

    That does indeed seem heavy for an empty boat. Maybe it is for fully loaded. Yes it would help to know if it was sail or power!

    I have several trailable plywood catamarans in that size. The Skoota 20 and 24 powercats. Janus, Wizard, Acorn, Eagle, Saylon are sailing catamarans.

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  4. smartcat
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    smartcat Junior Member

    It is a sailing/cruising cat and weight is fully loaded. Empty weight should be about 750 kg.
    Mr. Woods, i know your designs and I think, they are great. I also know your video about your trip at the baltic sea. something similar I want to do with my design and naturally coastal sailing.

    But i think, i dont need a boatdesign, but only a hullshape for my needs. And i have the idea, that the new designs get wider to the bow than in the past.

    I want to try it with one central board.

    Michael
     
  5. Richard Woods
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    Richard Woods Woods Designs

    Thats a bit like saying "I only want the fuselage, not the wings" when designing a plane, or telling an architect "I already have the foundations" when having him design a house. All aspects of a boat are interdependent and cannot be taken in isolation.

    You should check the history of the Shearwater and Stilletto 27 catamarans before going the central daggerboard route.

    I didn't understand your "bows are now wider" comment

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  6. TANSL
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    TANSL Senior Member

    Although I guess I understand what you mean, I would point out that it is impossible to have correct "hull shapes" if not taken into account all other aspects of a design.
    You can get a very nice "hull shapes" but totally wrong for your project. I guess you understand this. So asking for "hull shapes", nothing else, it makes no sense.
    If you want "hull shapes" for your needs, you need a design and if you do not itemize what your needs are, I do not think anyone can advise you about shapes.
     
  7. Alik
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    Alik Senior Member

    Hull shape is designed for the purpose, say speed, capacity, achievable displacement, stability, seakeeping, construction method, aesthetic considerations, etc. 'Give me a good hull shape' is just as useless as asking for a pair of shoes without checking size.

    I published a paper in IJSCT on catamaran design, there are hull types and their application...
     
  8. smartcat
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    smartcat Junior Member

    Thats a bit like saying "I only want the fuselage, not the wings" when designing a plane, or telling an architect "I already have the foundations" when having him design a house. All aspects of a boat are interdependent and cannot be taken in isolation.

    You should check the history of the Shearwater and Stilletto 27 catamarans before going the central daggerboard route.

    Hi Richard, no, it is something like i want to eat a steak and don't want to by a cow. Everything depends on the others and so my questions is more generally. It seems, that the catamaran hull shapes move from maybe for example on the first Shearwater designs a canoe hull to a surfboard hull in the underwatership area and that tey are becoming more flat at all.

    Could we say, ist should be similar to a NACA-Profil from Bow to stern in the top view and in the sideview from stern to bow for more lateral area?

    I had a look at Shearwater and Stiletto. But, of what I am thinking ist one central daggerboard underneath the platform.

    TX Michael
     
  9. smartcat
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    smartcat Junior Member

    Sorry, I have not understand yet how to make a "qoute":-(

    So this my answer to:
    Although I guess I understand what you mean, I would point out that it is impossible to have correct "hull shapes" if not taken into account all other aspects of a design.
    You can get a very nice "hull shapes" but totally wrong for your project. I guess you understand this. So asking for "hull shapes", nothing else, it makes no sense.
    If you want "hull shapes" for your needs, you need a design and if you do not itemize what your needs are, I do not think anyone can advise you about shapes.

    I am not looking for a 'correct' hullshape', but a few to compare to my design. I think, I itemized a a very few: it will be a short boat under sail wirth some load.
     
  10. smartcat
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    smartcat Junior Member

    Hello Alik@all
    Hull shape is designed for the purpose,
    say speed: yes, under sails
    capacity,
    achievable displacement; 1350 kg
    stability: yes
    seakeeping:yes
    construction method: plywood or plywood and wooden batten underwater
    aesthetic ?
     
  11. smartcat
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    smartcat Junior Member

    Thank you all for your answers. I think, it is a difficult theme. Becaus, if you have any knowledge, it is your capital. For me it is nearly the same. I spent a lot of time in designing my own boat and I dont want everbody to built it for free after all the time I spent on this design. And I'm sure, I will built it. But with a little help it would be a better boat. I will leave some pics of the designs model in a few days.

    Michael
     
  12. gonzo
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    gonzo Senior Member

    Probably you will get better feedback if you post the design you have now.
     
  13. smartcat
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    smartcat Junior Member

    Fotos of the designs model

    Here are some Fotos of the model of my design. Not everything is ready and some things will change. Especially the hull! But I think, that is the reason to make a model first and you can imagine, what I am talking about.

    Michael
     

    Attached Files:

  14. gonzo
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    gonzo Senior Member

    Are planning on a flat bottom or is it still not decided? Otherwise, the proportions look average, which is a good thing.
     

  15. Doug Lord
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    Doug Lord Flight Ready

    =======================
    Nice job on the model! Good luck......
     
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