Simple idea, kinda.

Discussion in 'Multihulls' started by scoobert, Feb 23, 2013.

  1. scoobert
    Joined: Feb 2013
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    Location: medusa ny

    scoobert Junior Member

    So my brief idea was this.
    Take your typical fuel storage tank of large size,
    say 12-14' diameter about 60' long.
    cut it in half.
    add bracing across the tops, say 19# per foot I beam.
    put hydrodynamic ends on it. add propulsion, and close the top of the cabin,
    wala, a multi! you would have to finish it off, but i can't see the true need for stiffeners beyond welding some simple braces in key locations. also is there any real issues with a completely round bottom in a cat?
    i just do not see why this is not done on a small scale. would be VERY cheep.
     
  2. Submarine Tom

    Submarine Tom Previous Member

    Welcome to the forum there scoobert.

    Nothing wrong with a round bottom, my girlfriend has one!

    Question: How are you going to safely cut that fuel storage tank in half?
     
  3. scoobert
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    scoobert Junior Member

    assuming it was a diesel tank, easy.

    and thanks for the welcome.
     
  4. CutOnce

    CutOnce Previous Member

    Darn fine question. Had a local high school lad blow himself to Kingdom come cutting a barrel in half for a school shop project. Was intending to make a barbecue, not become one.

    Washing residue and venting isn't enough. Think about it - enclosed space, air/fuel mixture and ignition potential. There isn't enough savings in this to make me want to try.

    --
    CutOnce
     
  5. scoobert
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    scoobert Junior Member

    you do know diesel does not explode with a flame to it right?
     
  6. warwick
    Joined: Jan 2012
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    warwick Senior Member

    The problem may be knowing what was stored in it in the first place.

    I would think you would still need to exercise caution when cutting it any way.
     
  7. scoobert
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    scoobert Junior Member

    it would be obvious with careful inspection.
     
  8. Submarine Tom

    Submarine Tom Previous Member

    There are a number of ways to do it safely.

    If it were me, I'd do them all.

    Scoobert, you didn't answer my question...
     
  9. CutOnce

    CutOnce Previous Member

    They use tanks for many things - fuel oil, propane, natural gas, acetylene - could be anything. I worked at a brewery during University and one guy got killed cleaning a hops tank. Enclosed spaces and gases have since scared the crap out of me - because I would have jumped in there without hesitation if the foreman had told me to.

    Worse than worrying about the labelled contents, if I were getting a tank from a scrapyard I'd worry about the fifteen things it was used for that didn't get labelled - and the combinations of chemicals created over the years of service.

    You want nightmares - read the manufacturer's safety and data sheets that are available for anything liquid you work with.

    --
    CutOnce
     
  10. scoobert
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    scoobert Junior Member

    i didnt understand the question?
    do you mean the actual cutting?
    plasma torch. leaving a bit of material to hold it together, then finish while securing the upper half on a rig and the bottom half on a stand.

    or were you referencing the prior usage of the tank?
    if diesel, just cut it, if gasoline, there will be more precaution.
     
  11. scoobert
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    scoobert Junior Member

    i can contact the local hazmat team and have them bring an air-gas analyzer over to check it out.
     
  12. Submarine Tom

    Submarine Tom Previous Member

    Okay, this is starting to get a bit comical.

    First, thanks for answering the question (sort of).

    It concerns me a little that you don't understand the question.

    I'm not sure how to reword it any simplier.

    The key word in there is "safely".

    So, what "more precaution" did you have in mind?

    Sorry to be holding back your thread from blossoming into your boat project but if you don't survive the initial cutting then it's of little interest anyway.
     
  13. scoobert
    Joined: Feb 2013
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    scoobert Junior Member

    its far from being my boat project. i will either be getting a commander, or building a bruce roberts. but i wanted to find out why NOT to do it this way.
     
  14. scoobert
    Joined: Feb 2013
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    scoobert Junior Member

    the more precautions is the air-gas analyzer i mentioned.
    gasoline evaporates, and can be dryed out.
    lets assume the tank is diesel.
     

  15. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    Besides safety and I think that can be solved, relatively easily.

    Most tanks are too wide for their length.
    Multihulls need to have narrow hulls so they work well. Too wide and you basically have a raft.
    You might want centerboards, dagger boards, or leeboards so you won't just go sideways, but you probably know that and just hadn't gotten to the discussion.
    Round ends will push a lot of water up front and suck up a lot of water in the back when you are moving.
    An I beam would work well for setting up the mast, but the beams (front and back) need to be able to take torsion or twisting when you are out in waves, and an I beam is not very good at torsion. If it is strong enough for torsion it will be extremely heavy - not good for a multihull.
    Steel is a very poor material for a multihull, too dense. Just because it is steel does not mean you won't need stiffeners inside. Pressure vessels are not designed for bending and loose most of their stiffness when cut in half.

    You will end up with a useless boat no one else will want (can't get rid of it) that you will not want to sail.

    The hull is only about 30-40% of the total cost, be a pitty to waste the other 60% of your money and time.

    Other than that - sounds like an idea.
    Post a picture when you get done.
     
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