Would that catamaran ever sail?

Discussion in 'Boat Design' started by john5346, Apr 23, 2013.

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  1. DennisRB
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    DennisRB Senior Member

    [​IMG]
     
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  2. troy2000
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    troy2000 Senior Member

    I've been extremely pleased with the little blue canoe. My son wound up stationed in Korea, so I've had it to myself for a while. I haven't managed to catch many fish from it, but I've probably entertained a lot of them while trying....

    After a couple of earlier builds over the years, I finally hit a sweet spot with the shape of the hull. The older versions tended to veer right if I leaned the canoe left, and vice versa, but this one tracks as straight heeled as it does when flat on its bottom. And although I don't have any scientific measurements to prove it, it just generally seems to slide through the water with less fuss.

    I don't think there's much doubt John is young. Oh, to be a teenybopper again and know everything.:)
     
  3. john5346
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    john5346 Junior Member

    Yes. That is a NASA design.
    [​IMG]
     
  4. daiquiri
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    daiquiri Engineering and Design

  5. kerosene
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    kerosene Senior Member

    I seriously recommend that you (or anyone else) will NOT choose the advise they follow by how much they like to hear it.





    :rolleyes: seriously.
     
  6. kerosene
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    kerosene Senior Member

    I too think John is just trying to pull reactions. His posting style is such a caricature of today's ignorant stubbornness that its hard to take it being for real.

    however I was so bloody bored that I made this to prove a point. 1st one is juts vertical sides bent to a curve. As stated many times here bottom and top would be just scribed. Every piece (except top and bottom) are rectangles. Using a jigsaw, or whatever you call the powersaw with zig-zag blade, cutting curves is fast.

    With 2 more curved cuts you can have rocker - as in the 2nd one. Or you can also introduce flare like the 3rd one. All are way simpler to build than what is originally suggested. And one really has to be dense and of zero engineering mind to not see why flat stern (rear) and sharp angles don't flow well. Ever seen an airplane?

    anyway getting besides the point.

    see:
    http://www.youtube.com/watch?v=1xHmvLBmnPE


    apparently I am unable to embed a youtube video. Oh well.
     
  7. john5346
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    john5346 Junior Member

    That is a nice demonstration. I like how easy it looks but I still think it needs clamps, pressure, correctly applied epoxy and plywood cutting to put all parts together.

    I wanted to know if my shape would sail, since I had sincere doubts it could. It was possible that existed some hydrodynamic rules it would move the boat in strange directions or that sailing was impossible but everybody said it will sail.


    I prefer my boat with rectangle and triangle geometry, if you all like curved hulls, it is ok.


    We dont need to talk about it anymore. Bye.


    It will sail.
     
  8. daiquiri
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    daiquiri Engineering and Design

  9. kerosene
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    kerosene Senior Member

    indeed
     
  10. Edwardn
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    Edwardn Junior Member

    So he has been called and compared to everything under the sun down to a midnight thief of material but has the question of will it sail or not been answered?? There are mini pontoon boats similar to his design used with motors but thats a different story... This poor ******* comes on here asking if it will sail and the consensus is it will but poorly but then gets rips a new arse hole for not taking the professional advice so freely given to him... and so what to each his own, but you all gang up on him for what? To make your selves feel special?? You Troy said yourself it took a few try's to get your canoe design right and rightly so but were you chastised and downgraded during the process? Did you post your first attempts here? Wouldn’t it be better to let him build his damn boat the way he wants and report back the flaws , would flaws and confirmation satisfy your curiosity and boost your egos of I told you so? Ya’ll have to remember that being a open a free discussion will bring in everyone from all walks of life looking for answers and asking question that may seem trivial to you but is important to us and you do have the option of answering or not and when you degrade a person for asking a simple question it degrades the forum... and in this thread you all should be ashamed of yourselves for the personal attacks you made, you are not professionals but a bunch of hacks, think back to the first design you drew and the responses you got.
    Edd.
     
  11. FMS
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    FMS Senior Member

    It is difficult to respond only to the specific question asked when it's clear it is part of an illogical SOR. (the only stated requirement was to build in angles which are bad for efficiency, more difficult to construct from thin plywood, and a structural weakness.)

    [​IMG]
    Practically anything can be built. This has performance disadvantages. It is also very difficult to build well with all those stress points, joints which need to be sealed, and additional places for water to collect and rot on the interior.

    If there were real construction advantages to a hull shape such as this, it would merit analyzing how poorly it would perform in comparison with a conventional design. With no advantage, the purpose of the thread can't be understood. Still, I wouldn't stop someone from building it and observing, taking proper safety precautions. I said this on the last page. The advice to build models first is even better.
     
  12. FMS
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    FMS Senior Member

    Kerosene took the time to create an animation even to address the mistaken preconception that building with hard angle cuts and thin plywood is easier - it is not:

    Sometimes experience with wood and glue is necessary to understand why something is done a particular way.
     
  13. Edwardn
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    Edwardn Junior Member

    Welp, I thought the original question was will it sail? will it?
     
  14. FMS
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    FMS Senior Member

    One problem is the first post combines a very simple question and a statement together:
    Yes it would sail, although not well compared with a better designed hull.
    I don't find the statement "if you say it would sail, then I will build only that type of boat" logical. And going up to a 27 foot version, there is much more material and time involved. It isn't my money invested in materials, so I wouldn't stop anyone from building what they want, provided they do so taking adequate safety precautions. I also couldn't recommend investing that much material and time without exploring the reasoning behind it and suggesting other better options.
     

  15. messabout
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    messabout Senior Member

    Edwardn; You are correct in that we were a bit hard on the OP. He deserved it. He insulted an enormously generous and brilliant adviser early on. That did it for me. I did not attack the OP personally but I did berate his design and proposed building method and so did the others.

    We get a lot of "newbies" who come to the forum, asking questions or seeking advice. Most of them are grateful for such good counsel. A few of them are hard heads who do not know the pointy end from a hole in the ground, yet they argue that their way is as good or better than that of our acknowledged experts. That attitude becomes wearisome and we sometimes snipe at the offender.

    This whole forum is inhabited by good people who know a thing or two about the objects of their passion. They give freely of their knowledge and experience and they need not suffer fools lightly.
     
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