Building a small work barge with plywood

Discussion in 'Boat Design' started by indianbayjoe, Nov 20, 2010.

  1. brian eiland
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    brian eiland Senior Member

    Photo & Drawing Image Software

    Here's some good photo, drawing, and image management software I was turned onto a few years ago...and its free
    http://www.irfanview.com/
     
  2. SamSam
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    Location: Coastal Georgia

    SamSam Senior Member

    That looks interesting. I'll try it, thanks.
     
  3. BATAAN
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    BATAAN Senior Member

    Barge in plywood from experience.
    Pre-coat all ply both sides with two coats of WEST epoxy resin.
    Bottom built upside-down of two layers 3/4 ply, butts staggered over 2x6 on 16" centers frame. All glassing and bottom paint completed.
    Turn bottom over, erect 2x6 side frames on ply gussets.
    Sides are one layer 3/4 with butt blocks and good fastening for ply butts.
    All joints are epoxy/filler with s/s screws. All corners are filleted. All wood is coated with two coats epoxy.
    Important to have drain plan with limber holes. If you want to find damage in any wooden structure, ask "Where does the water go?" and look there.
    Deck is most important for long life. Strong frame with two layers ply, crowned at least 1/4" per foot of beam for drainage, sheathed with glass/epoxy and painted.
     
  4. brian eiland
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    brian eiland Senior Member

  5. indianbayjoe
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    indianbayjoe Senior Member

    any pics bataan
     
  6. BATAAN
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    BATAAN Senior Member

    No pics on that one. Two weeks of insanity many years ago, but basic epoxy/plywood techniques are pretty straightforward.
    Ruell Parker's book "The New Cold-Molded Boatbuilding" shows cheap wood and epoxy methods.
    In designing a plywood/epoxy barge:
    Rakes on both ends are good usually.
    The bilge water is a major factor in longevity, so must be carefully planned for.
    The integrity of the deck also.
    A clever friend built a steel barge by building the sides first, joined by a half piece of pipe. It was easily flipped over laying on sleepers and most of the welding was down.
    Then he cut the pipe in half, pulled the sides apart and set them up vertically and upside down, framed and plated the bottom, set it right side up, built a steel half deck and wood house and moved in. Nice houseboat built like a work barge and finished in six weeks. It had nice 1/4 pipe corners at the ends, chine and deck. Lovely job. Sorry no pics.
     
  7. indianbayjoe
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    indianbayjoe Senior Member

    is there a simple formula to figure out how deep a cylinder will sink if we know the weight? Its easy for a square or rectangle but i can't think of one off the top of my head
     
  8. SamSam
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    SamSam Senior Member

    To find the area of a circle multiply the square of the radius times pi. If you had a circle two feet in diameter, it would be 1 x 1 x 3.14 = 3.14 sq. ft., a circle 10' diameter would be 5 x 5 x 3.14 = 78.5 sq ft. Then you multiply the length to get volume, etc.
     
  9. rwatson
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    rwatson Senior Member

    I like to use metric measurements, because they convert to displacement much more easily

    Formulae
    -------------
    PI x length x radius ^ 2

    Example Figures
    ------------------------
    Pi = 3.141592654
    Length of Cylinder = 300 (centimetres, = 3 metres)
    Radius of Cylinder = 15 (centimetres)
    Radius of Cylinder Squared = (15 x 15) = 225

    So the answer is :
    = 3.141592654 x 300 x 225

    = 212057 cubic centimetres


    Convert to Litres
    --------------------------------
    / 1000 to get Litres

    = 212 litres

    Convert to Displacement in water
    -------------------------------------
    1 Litres = 1 Kilo
    = 212 Kilos of displacement in fresh water


    Convert Kilos to Pounds
    ----------------------------------------
    1 kilogram = 2.20462262 pounds
    = 466 pounds of displacement


    Hope it helps more than it confuses
     
  10. indianbayjoe
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    indianbayjoe Senior Member

    Happy new year to all. Thanks for all the info. The project continues
     
  11. indianbayjoe
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    indianbayjoe Senior Member

    Well i think were moving in the direction of wood. All the prices for either plate steel, new and used and float tanks and used propane tanks and already built barges are way too high. We have negotiated a pretty good price for the plywood and I can buy all the fiberglass materials and epoxy at wholesale prices anyway so now its just the fine tuning of the structure.

    One question one of you may be able to help me with is the mounting of the crane I bought. I picked up a #4000 electric truck crane like this one. It has a 4 bolt base and we were thinking of tying the deck to the internal bulkheads and stringers with galv steel plate angle all the way down to the bottom. My concern is the downward compression when picking something up or the upward shearing of the deck on the opposite side. I think that if we add some internal structure in addidion to the 2' X 4' compartments in the diagrams, then tie it all together maybe that would work. Should we consider some plate steel or aluminum under the base of the crane?
     

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  12. waikikin
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    waikikin Senior Member

    Hi Joe, I've been following your thread here with interest as I'm keen for a similar but smaller barge. Just out of interest have you considered using 3x2 or 4x2 timber in the intersections rather than the glass & resin tape, from here that sounds like a stack of taping, same distance or possibly half with timber but buttering up some glue & gun nailing or screwing the timber on seems quicker & maybe cheaper & might hold the bulkheads & other components straiter for set up, just thinking out loud on this:) For your crane, usually when I've looked at the hydrolic knuckle boom cranes you see here like Hiabs etc they have a clamping arrangement that sets the crane around & under the chassis rails of the truck, for timber I imagine that you need some hefty & deep hardwood sub deck framing that spans multiple frame bays to bolt the base to & if your deck is in a softwood ply you will need some heavy plate over it- bigger than the base or a frame matching your sub deck framing to spread the load, any ways make it over the top strong! All the best in your endeavours from Jeff.
     
  13. indianbayjoe
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    indianbayjoe Senior Member

    Yea, we know its a whole lot of taping but that turns out to be the strongest construction method aside from throughbolting everything to internal timber framing. This has also turned out to be a little experimenting now but with the past repairs and projects and looking at modern construction methods i think were on the right track. We did a little testing with a mock up of the design and feel that the strength is definetly there. In the area of the crand i think were looking at tripling the internal frameworks and doubling the plywood decking and bottom and tying it all together somehow with steel as well as the glass and epoxy.
     
  14. indianbayjoe
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    indianbayjoe Senior Member

    We got the price of 3/4 AC exterior plywood down to $31.00 per sheet. We need about 50 sheets so thats not too bad. We laid out the deck layout on the garage floor today and there will be plenty of room at 12 X 24. We were thinking of extending it to 28 feet but that won't be necessary. Our calculations work out to have a load capacity at half submersion of about 12,000 pounds so that is more than plenty. With the crane located about 7 feet from the bow that allows us to use almost the max lift off the bow.
     

  15. Typhoon
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    Typhoon Senior Member

    You could always build a couple of ballast compartments into the rear of the barge, flood them and be able to use your crane more safely. Or flood one side etc.

     
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