Last question for a while; Steel framed cabin with aluminum pontoons

Discussion in 'Boat Design' started by parkland, Aug 8, 2013.

  1. parkland
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    parkland Senior Member

    OK,

    So lets say somone built a steel framed boat deck and cabin, is there any reason to not use aluminum pontoons as flotation, assuming they are spread apart far enough to make it stable, and they are connected with bushings or something so there is no steel-to-aluminum contact?
     
  2. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    Many ships are built with steel hulls and aluminium superstructures, primarily for stability purposes (they don't want the weight of all that steel high up, if it can be built much lighter in aluminium).
    Not too many ships around with aluminium hulls and steel superstructures......
    But you could always be a first! :)
    (OK, I realise that ships are rather different to pontoon boats).

    But surely it would be more logical to have steel pontoons if you are building a steel deck / house, or ally pontoons with an ally deck / house?
     
  3. parkland
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    parkland Senior Member

    Well, I've been fighting with boat ideas for a long time.
    There are several threads in here, boats I found, ideas to build them, but I just haven't run accross something that I want, and is practical for my amount of skills, or skills of people nearby.

    It's definately an upside down idea, but since the pontoons stability is based solely on the width between them, logic (or at least my logic) makes me think that the issue could be resolved with spacing them farther apart.

    BTW, when I meant steel cabin, I didn't mean steel plate cabin; I meant steel tubing frame, built as lightly as possible, with thin roofing metal style sheets for the walls. Or maybe something else light. But definately not steel plate or anything like that.

    I was just entertaining the thought of buying aluminum pontoons, and building the cabin and frame out of steel tubing, and having the pontoons maybe fold outward somehow, to gain width and stability.

    My goal was, and is, to make a houseboat of some kind, that can be trailered behind a 1 ton truck.
    I have basic welding skills, and know a bunch of guys that can weld steel. Problem with building a hull of steel, it would rot out from insulation trapping moisture.
    Thought about an aluminum hull, but there isn't many people that know how to weld aluminum too good around here.
    Thought about buying a boat, but most this size are cabin cruisers made for planing, and are fat and stubby with v8's in them.

    A really nice boat, probably the closest to what I'm thinking, is the yukon delta houseboat; it is basically a camper with a hull on the bottom, very close to what I wanted. I have been on the prowl looking for them too.

    Basically my ideal perfect boat is something like a yukon delta, 8.5' wide, 36' long, higher "pointier" bow, the rear of the hull raked up a bit, and a 4 cylinder isuzu diesel or similar.

    Eventually I will figure something out.
    I have to, the odds are running out lol.
     
  4. boat fan
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    boat fan Senior Member

    Why would you need insulation inside a pontoon ?
    If anything , it would serve better under the floor.....

    Light steel tubing can certainly be used to frame out a cabin.
    Aluminum skin and rigid foam insulation , some lining inside , ( sheet material).

    Don`t see a problem with any of this.
     
    Last edited: Aug 9, 2013
  5. SamSam
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    SamSam Senior Member

    http://groups.yahoo.com/group/SeaCampers/

    http://groups.yahoo.com/group/SeaCampers/message/6208

    The motor alone is almost worth it on this one...

    http://ontario.kijiji.ca/c-cars-veh...t-other-Houseboat-for-sale-W0QQAdIdZ510367289
     
  6. dskira

    dskira Previous Member

    Any reason to don't use aluminum for the deck and cabin :?:
    Any reason not to built the whole in steel :?:
    Any reason for this question :?:
     
  7. Petros
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    Petros Senior Member

    if you separate the dissimarl metals with sealant or gaskets at all contact points there should be no problem at all. there are lots of structures with dissimlar metal contact, like aircraft, bridges, etc. You just need to keep the two metals from coming in contact with a coat of sealant or a gasket, install the fasteners "wet" with sealant.
     
  8. parkland
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    parkland Senior Member


    Insulation for the walls, at least a little so it can be slightly cooler or warmer than outside, depending on temperature.
     
  9. parkland
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    parkland Senior Member

    If I can't weld the frame out of aluminum, I'd think aluminum panels would be a disaster.

    My math tells me that steel pontoons would be to heavey, and the craft would weight too much to tow.

    A 4x4x36 1/8" steel box would weigh 2800 lbs, so that would be 1 pontoon plus all the internal framing yet. No way in hell it would work.
    The set of aluminum pontoons 36" x 36' are only couple thousand pounds for both.
     
  10. parkland
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    parkland Senior Member


    Thats sort of what I was thinking; it should work fine as long as rubber or plastic bushings are used to keep the steel from touching the aluminum.

    I am not all fond of this idea, but it might be the right idea for the right person.
     
  11. boat fan
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    boat fan Senior Member


    Yes , nothing wrong with any of that , just needs some measure of care when you assemble the thing.

    I would look into SIP ( structural Insulated Panels ) , to minimize most framing.

     
  12. PAR
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    PAR Yacht Designer/Builder

    There's absolutely nothing wrong with the idea of a steel support structure as the frame fork for what ever you put on the deck. Naturally, as I'm sure you're aware, you'll want to keep things light, but some angle, flat bar and tubing is a great way to get it done.
     
  13. parkland
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    parkland Senior Member

    Basically, I was thinking maybe it would work to use heavier stong steel to build a deck very similar to a flat deck trailer.
    On top of the flat deck trailer, build the houseboat cabin in a similar wat to a hi-lo camper, where it collapses for transport.
    The cabin should collapse to about 4 to 5' high.
    The cabin would be all light guage metal, and light weight
    construction as much as possible.

    The pontoons would attach to the bottom frame with arms, and fold on the roof for transport.
    They would fold out for use in the water, and stick out away from the cabin about 5' on each side.
    There would have to be some kind of locking mechanism to hold them in place.

    The entire unit could be it's own trailer, with the wheels adjustble height by hydraulics,
    and the front hitch also adjustable.
     
  14. dskira

    dskira Previous Member

    Transport maximum hight is 13'6" to 18" depending the State regulation.
    A beam of 8'6" in a square structure give a lot of space.
    Collapsing superstructure is quite a complicate thing to achieve.
    Why you need all that folding for?
    Hydraulic system are complicate and very heavy.
    Why not a pontoon with a hitch, and the trans axle and wheel permanently attached? With a nice recess for the wheels the design can be quite simple and elegant.
    Anyway a water/land transportation system will never be as performant as a car or as a boat but enough to have a great journey on the road and on the water, so why not making things simpler, cheaper and practical.

    But perhaps I am ahead of myself, and I didn't understand what you are after.
    In that case I apologize for my post.
     

  15. SamSam
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    SamSam Senior Member

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