My KAT Design

Discussion in 'Boat Design' started by thiago1979, Mar 29, 2016.

  1. thiago1979
    Joined: Mar 2016
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    thiago1979 Junior Member

    Catamaran Frame ideas. I need some help with Design and Stability of a Catamaran. This is going to be my Home and Travel Sailboat. I do not have experience with Design or Building a boat of any kind. All I have done so far is take a Sailing class. All I do have is Desire to be free from this so called modern world, so I decided to build a Catamaran for me to live in for as long as I possible can. I have been playing around with Autodesk 123D and came up with a basic design on what I would like to achieve. I still don't know how to post images here. I have been looking everywhere for an Attach button. Also I am completely alone in my search. I live in Miami, Fl and have no one to talk to about this project. If you were ever lost in something like this you know how frustrating this is. My basic idea is to create a design and build a small catamaran with two full size beds and two restrooms. I would like to place a Dinghy inside the middle part of the boat, so I don't have to toll things on the back of the boat. I did a little Welding(MIG) and know the principles. Other then that I don't really know anything. Thanks for your support!
     
  2. TANSL
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    TANSL Senior Member

    Welcome to the forum. I hope you can find here what you need.
    What does exactly mean for you "some help" ?. If we knew what your knowledge, knowing what it is to design a boat, we could know what you need. I mean, you should specify a little better what you already have and what you need to buy.
    Good luck.
     
  3. Rurudyne
    Joined: Mar 2014
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    Rurudyne Senior Member

    http://www.multihull.de/technik/catdimension.pdf

    ... the above may be useful to help you know what to expect and sketch out some of your ideas; however, multihull construction, you were asking about a frame, because of the bridge or wings (tri), is more complex than monohull. It wasn't too long ago a large plywood home design suffered catastrophic breakup which is hardly surprising because one could see the bridge deck bending/not-quite-buckling just floating in calm water. You may very well be able to do much better than that on your own than that guy did, but why risk not turning to a NA when you'll still be plunking down a hefty chunk of change on building?
     
  4. Manfred.pech
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    Manfred.pech Senior Member

    Live it to the full: http://www.boatdesign.net/forums/multihulls/how-dimension-sailing-catamaran-22274.html and http://www.boatdesign.net/forums/downloads.php?do=cat&id=1
     
  5. thiago1979
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    thiago1979 Junior Member

    My thoughts on the Kat is that it definitely needs to be metal, depending on the finance side of things if I can get away with the 500 aluminum series, great if not I could care less if I have to make it out of Galvanised metal. I really want to build this Kat!
     
  6. thiago1979
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    thiago1979 Junior Member

  7. TANSL
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    TANSL Senior Member

    I would not want to disappoint but this structure has serious shortcomings.
     
  8. thiago1979
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    thiago1979 Junior Member

    Tansl
    You are correct Sir. This is what happens when I don't know anybody who can help me. And get this if I keep on going alone I can do even worse. Indeed I am looking for a friend in this Forum to set me straight, unfortunately this days are not like the good old days. Its easy and hard at the same time to look and ask for help. I assumed to begin my journey here.
     
  9. TANSL
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    TANSL Senior Member

    Design a catamaran is not a simple task and, specifically, the structure requires studies than monohulls do not need. So, as I noted in my previous post, you should start thinking that, perhaps, you have to pay someone to get help.
    Sorry to be so abrupt and so materialistic, but that aid will need many hours and a lot of knowledge.
     
  10. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    Find a boat design that is close.
    Save your life and money.

    There is lots to a boat besides 2 beds and 2 restrooms, especially if you are going to live on it.
     
  11. Rurudyne
    Joined: Mar 2014
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    Rurudyne Senior Member

    Okay, some comments:

    Avoid sharp corners in your sheet metal as these will result in stress and cracking.

    The majority of your strength in a beam is not in the webbing, but in the extreme top/bottom and/or front/back depending on how you expect a structure to flex (or resist flexing) under load. Think girder design.

    Also, major structural elements in a bridge deck would benefit from box construction ... they are subject to torsion and not just up/down or back/forth stresses.

    As you're wanting to use metal you need to avoid construction like this:

    |
    [ ]
    |

    or

    |
    ( )
    |

    Where cross pieces intersect a weld or joint in a beam. This kind of joint has caused many failures, including the collapse of a walkway at a Hyatt that killed lots of folks. They fail because the attaching plates can pull through the weld. Rather, have cross members attach away from any seam.
     
  12. thiago1979
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    thiago1979 Junior Member

    Rurudyne

    Finally some great point of view to keep in mind. You don't really know how much your information is valued by me. I understand if the entire sheet would be a single frame to add to the line up. I assume the sheet cut to that dimension would cost a lot more. I will be modeling a sheet that you don't need to add parts to it. In my mind I was trying to make this effective and inexpensive. Unfortunately money like always play a major part on my ability to achieve this project. At this time I have around 20k saved up to buy the metal. Not even talking about a place to build the boat. As you can see Any knowledge pointing me on the right direction would be much appreciated just like you have done here. I will keep you posted with some images to show. Thanks again
     
  13. thiago1979
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    thiago1979 Junior Member

    You are right Upchurchmr! There's a lot to do and there's many steps. As Rurudyne has pointed me on the right direction. Some positive criticism and guidance is what I was looking for. I am but a baby in this vast space of experience individuals, however with your efforts and my devotion to achieve this project I believe an understanding and final design of the frame can be achieved. Again I am grateful for your support!
     
  14. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Welcome to the forum.

    Given the assumed size and scale of a project like this, also your engineering and design talents, plus your sailing experience level, you shouldn't even think about self designing and building, a yacht like this. This isn't meant as an insult, just an observation of your previous admissions.

    Simply put, would you ride in an elevator that was designed by someone with your design, engineering and operational experience, say up to the 20th floor of a building? Would you fly in an aircraft, designed and built by someone with your skill sets? Why not, are you chicken? You don't have to been chicken, to simply recognize the realities of those two situations. The exact same thing is true of self designing and building a yacht like this. How far from shore will you risk - far than you can swim back if necessary?

    It's one thing to ask for some help, but this isn't what you need. You need an education across several disciplines.

    Your best advised, to simply purchase a set of plans and make modest adjustments to suit your needs.
     

  15. thiago1979
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    thiago1979 Junior Member

    Given the situation I find myself in. I live in Miami and am surrounded by ocean from both sides. I have been here for 5 years .Do you know how many times I have seen or gone to the beach? Try about 10 times. Do you know how many times I have seen pictures and videos of clear blue water? Too many times. Now I have this yard (Plan) I planted some seeds in it. (Inspiring ideas, dreams, hopes). One way or another I will bear the fruits of my efforts. You could say in your experience level that I am kinda crazy. I would say you and I may not be so different if you ever considered a life sailing around the ocean freely so exciting and beautiful. This is to put into not so dramatic expressions. You are just like me, in fact all of you are like me. We all choose this life and and at one point you didn’t know much about it. Sure could be your Dad or some friend introduce you to this knowledge, but at one point you had to be thought and if you had to be thought you did not know. This is me I am the I don’t know it and I am seeking hope and knowledge in all of you who have grown up in both knowledge and experience. Actually I would fly an ultralight plane built by me first if I ever would let it out of my sight. I have ambition, hope and dreams and I have some ignorance and guts. The ignorance part is what I don’t know about, so you’ll find me here pleading for help, hungry for knowledge.
     
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