HELP!......square pontoon design

Discussion in 'Boatbuilding' started by Big Will, Mar 13, 2012.

  1. Big Will
    Joined: Mar 2012
    Posts: 3
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    Location: Louisiana

    Big Will New Member

    Hey everyone,

    I am a new member to the site....but not new to house boat building. I have built two house boats the first was 24'x48' floating on 12' dia. fiberglass filled dredging pontoons 12" high. completely built it drafted 1.5" over kill i know...the second is a 24'x43' odd length because i used I-beams i had. it floated on 700gal. recycled fertilizer tanks with solid steel frame.....

    i am looking to build another house boat with a more contemporary and luxurious design. i have used recycled materials on the others now im looking to build my own. the house boat will be 18'x50', i know it is a little big to trailer and would require permits, but my father owns a trucking company and permits are not a problem.

    what i was thinking with the floatation........

    i want to use aluminum skinned square pontoons 4' wide 2' high with a 6"x6" 45 deg. angle on the bottom corners. the nose of the pontoon will be angled for deflection.

    questions?
    -what type and thickness aluminum should i use?
    -what type of frame structure should i use to attach the skin too.
    -1"x1" angle
    -do i need angle running the length of the pontoons on the inside for structural support or is it over kill?

    now for the framing.......

    i want to make it as light as possible and as durable as possible because it will be in a brakish or salt water enviorment. i dont want to use wood for obvious reasons. i was thinking about using 2"x4" tubing for perimeter frame with 2"x4" tubing at wall locations... and 1"x4" channel joist...

    thought?


    flooring.....

    the interior floor i was thinking i would put down a vapor barrie with 3/4" marine grade plywood.

    - what is the best way to attach the plywood to the aluminum frame? i dont want to use wood nailer strips! any suggestions?

    any ideas you have would be greatly appreciated.
    thanks in advance for all the help!!!
     
  2. Big Will
    Joined: Mar 2012
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    Location: Louisiana

    Big Will New Member

    94 views and no suggestions.......plz help!!!
     
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The questions you ask suggest no engineering or hydrodynamic experience or understanding. This means you need to hire someone to work up scantlings and structural elements.

    No one is going to take a guess at the loads imposed by your "arrangement", so contact a designer or NA or maybe a student of design, looking for something to cut their teeth on.
     
  4. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    There are also loads of aluminium building tips in the metalwork forum.

    Have you tried searching for proper plans on the internet yet ?
     
  5. Janpret
    Joined: Dec 2012
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    Location: Africa

    Janpret New Member

    Hey. BIG WILL are jou still here? Or any one else plz
    I am planning to build the same type of pontoon vessel, and need some advice plz. The "flot " as we call it here in Africa, meens float, needs to carry 3O tons for 12-16 pax, camping gear and 4 vehicles with trailers or small caravans. (a game viewing and camping vessel)
    She will slow cruise up and down a fast moving, 50 + meter wide river.
    My design so far- 2 pontoons. 150 cm wide, 90cm high, 15 meter long, each
    Bottom deck 15 meter long x 6 meter wide for the vehicles and or safari tents.
    Top deck, 11 meter x 5 meter, mostly for viewing and sunbathing and other fun stuff. O and the control room.
    I will mostly build it myself.
    Aluminum is 3 x lighter but also 3 x more expensive and needs an expert to weld tocgether so i opted for steel?
    My pontoon design is square with up angled nose, how much difference will it make to do a angled keel design? Do i build it with 3 millimeters thick steel sheets or thinner skin with frame structure?
    What and how many engine power would be minimum? My thought was 2 x 200 yamaha at the back and 2 x 60 in front to help with tight cornering?
    Does anyone know of design plans available that will help me with this tipe of pontoon?
    thank you
     
  6. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Welcome to the forum Janpret.

    I'm not trying to insult you, but without some knowledge of the engineering and hydrodynamics involved, designing a vessel like this, is just a guarantee to read about lots of folks drowning and lots of equipment being sunk, when the inevitable capsize or other "incident" occurs.

    A vessel like this requires a fair bit of engineering and understanding, of the dynamics involved. Asking folks to unwittingly place their lives and equipment, on a craft designed without some level of responsibility and expertise, is simply criminal.

    The design you've suggested is sufficiently complex, particularly as a passenger carrier, to require a designer or NA develop a set of plans. I know of no "stock" plans that would suit your requirements, maybe others will have a better idea, but the craft should be designed to suit your needs, which in itself suggests a custom or semi-custom piece.

    I have a couple of designs that could be altered to suit, but they aren't pontoon designs, which by their nature are load limited.
     
  7. Janpret
    Joined: Dec 2012
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    Location: Africa

    Janpret New Member

    Thx PAR
    it is because of my understanding of the engineering and risks involve in my project that i am seeking help in this forum. I have learned a lot from this forum sofar and I will not start building until i am 100% sure i have it right.

    This vessel has to be registered and certified by our authorities yearly with buoyancy certifications etc.

    Thx again Jan
     
  8. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    Aluminum in a salt water environment....
    All the pontoon framing should be the same material I imagine to minimize electrolysis.
    Don't use any treated wood as the new formulas will dissolve aluminum.
    Fresh water is more prone to rot wood than salt water.
    Not that I can engineer it, but you can't expect too much 'technical' advice on such slim information as to loads, power, water conditions, intended use etc.
     
  9. SamSam
    Joined: Feb 2005
    Posts: 3,900
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    Location: Coastal Georgia

    SamSam Senior Member

    Whoops! I see now the OP is out of date.
     
  10. Submarine Tom

    Submarine Tom Previous Member

    Would be nice to have an automatic "out-of-date" flag come up on these wouldn't it.

    If you agree, flag this post for the Moderator to view.
     
  11. Boat Design Net Moderator
    Joined: Feb 2010
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    Location: www.boatdesign.net

    Boat Design Net Moderator Moderator

    If a thread hasn't been replied to in a year (365 days or more), an "Old Thread Warning" currently appears with the reply section that requires a checkbox to be checked to confirm that someone wants reply to and restart the old thread. The idea is that this prevents accidental bumping of old threads, but allows for a follow-up or relevant additional information or discussion to restart if a perfect fit for the older topic.
     

  12. Submarine Tom

    Submarine Tom Previous Member

    Really!

    I've never seen it.

    Thanks.
     
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