Building Oyster barge (work barge)

Discussion in 'Boat Design' started by NewWaveDave, Aug 11, 2018.

  1. NewWaveDave
    Joined: Aug 2018
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    Location: Pennsylvania

    NewWaveDave Junior Member

    I've got a proletarian question for a proletarian project. I'm building a plywood sectional barge for my oyster farm, nothing fancy, each section 3' high x 15' long x 4' wide. Gotta make my own plans, not powered, gonna drag it out and spud it in. Do I need to put chine logs in the bottom (at the right angles) or will epoxy/thixotropic fillets give me a couple years of service (gonna take it out repaint once a year). Thanks!
     
  2. NewWaveDave
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    NewWaveDave Junior Member

    or maybe a different question....is the barge going to need a keelson?
     
  3. JamesG123
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    JamesG123 Senior Member

    What kind of loads is it going to take? Is it just going to be you paddling around to check on the beds or is it going to be a buoy for the oyster.... hangers? what ever they are called?

    Many light duty plywood boats are built as pretty much just a wooden box. I'd add at least one along any bottom seams and around the gunwales. But you can add as many stiffeners as makes you comfortable.
     
  4. NewWaveDave
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    NewWaveDave Junior Member

    It's gonna be a work station. Most likely be stationary with a boat bringing the oysters of various sizes in to be graded, cleaned, and redistributed. Gonna be a structure on it for heat when its cold and general protection (delaware bay) I'm going to consider a safe working load to be 1/2 displacement minus dry weight.
     
  5. JamesG123
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    JamesG123 Senior Member

    A pontoon boat kinda thing would have more stability. As stationary, something more square might be more practical/adaptable.
     
  6. Blueknarr
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    Blueknarr Senior Member

    Need a bit more info.
    1/4 plywood requires significantly more framing and reinforcement than 3/4.
    How thick is fiberglass incasement?
     
  7. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    Half submerged it would have a load of 5400# , coming close to 3 tons. That's a lot for something that small and narrow.
    Is it a deck barge, where you work off the top or a tub like barge where you work down in it?
     
  8. NewWaveDave
    Joined: Aug 2018
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    NewWaveDave Junior Member

    Good questions. Thank you. I was thinking 5/8 plywood with 6 oz fiberglass/epoxy, 1 coating. I was planning on 2x4 clear western red cedar for framing every 2' with 12" 45 degree braces attached to the framing cut from the 5/8" marine plywood at bottom corner of each riser. Planned on using epoxy barrier coat on the hull then EPS bottom paint. The framing is going to be complete across the top to support the deck (also 5/8" marine ply) and a 2x4 cedar chine around the top edge to support and also screw the deck into. The barge is going to be (2) sections of the above specifications bolted together. Hence, sectional barge, making a 4x8x15 work platform with more then enough displacement for anything I could possible fit on there. That's the idea, anyway. I am not emotionally attached to any idea except NOT spending $40,000 plus on something I can build for $4000. SamSam, my calculations are about like yours. I can't imagine possibly even getting that much weight on the barge....I more like the idea of being able to work out in the bay in some chop and not get washed off the deck, hence the 3' height of the barge.

    My thinking was that the keelson was good for helping to frame up a wooden boat and the chines being useful for framing as well. I was also thinking the keelson and chines might give some strength for a boat speeding along bouncing over waves. I was thinking that If I were to need a chine for the bottom, white oak would be good. I'm also open to a second layer of fiberglass. In fact, that's what I've been thinking. If fillet joints can be a structurally sound alternative for a chine on the bottom, I would prefer to go that way. I would also like to ditch the keelson if that can be wisely done. I honestly don't see myself putting more than a ton on the entire barge, both sections attached, at any given time. Is that enough information to help move things forward?
     
  9. JamesG123
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    JamesG123 Senior Member

    Do you mean a 3' or 4' deck height or total freeboard? From your description, I am imagining a hollow wooden box with all of its load; a few people, some stainless tables and lots of boxes of oysters all on top. Bobbing around with your center of gravity at 4' high with only 8' of beam can make for a tippy platform. You'll spill yer beer fer sure.

    A gridded box 18" tall at the bottom, with the empty space filled with foam will make a hella strong frame for the deck, make is unsinkable and self-draining if not unduly loaded, and reduce the C0G to a reasonable height while maintaining a decent weather freeboard. Yeah it means moving gear and cargo up and over the sides, but I think any other way would require either heavier construction (steel, concrete) and/or ballast.
     
  10. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    Why not build 8x16 as one piece vs the 2 you have planned?
    6oz FG is way thin.
    If you are using epoxy as FG resin, then no need for epoxy barrier paint.
     
  11. NewWaveDave
    Joined: Aug 2018
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    NewWaveDave Junior Member

    thank you for your replies. 8x16 too big for me think about handling as 1 section. in 2 sections, I think 2 people can probably flip it as necessary in the construction process. And then getting it from my house to the water, I was thinking each section could fit on the same trailer I will use for my skiff.
    And 3' deck height. Might do 2 1/2 deck height. How does one fill a giant rectangle with foam?
     
  12. JamesG123
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    JamesG123 Senior Member

    One doesn't. Unless one is building a bouncy house. LOL.
     
  13. Rurudyne
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    Rurudyne Senior Member

    More digression: usually filled with air. Part of why not securing one properly sometimes leads to tragedy.

    Me, being a very silly individual, wrote a parody version of Ghost Riders in the Sky called "Bounce Houses in the Sky" awhile back. I'll go and post it in the jokes thread.
     
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  14. Blueknarr
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    Blueknarr Senior Member

    Great reasons for subdivision.
    There are expansion foams sold as two components. Mix and pour. They usually absorb great quantities of water. I suggest gluing a few layers of cheap rigid insulation foam available at the home improvement center. They too will absorb water, but are easily changed.
     

  15. NewWaveDave
    Joined: Aug 2018
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    NewWaveDave Junior Member

    I appreciate all the input. I am going to redo my calculations with a 2 1/2 foot deck height instead of 3' and plan for 2 layers of glass. While it won't save money on plywood per say, it will save on epoxy, framing, and paint a bit. Total equipment on the barge should be (1) small 2x4 structure with windows and a stainless steel table, (1) trash pump for supplying the water to wash the oysters, fuel for the trash pump, oysters (hopefully lots of them), a fuel/oil spill cleanup kit, and extra hardware/ropes and other supplies for maintaining the oyster farm. Then once I get it running I'll figure out everything I did wrong and I will have a couple years to live with it and think about it before I do it again. And I'm thinking each section is going to cost around $4000 at this point making the entire project around $8000. I was reading that epoxy itself is not truly waterproof, that the barrier coat is needed to make it truly waterproof. I could save myself $400 a section if I don't need it. Anyone else think epoxy barrier is unnecessary with 2 coats of 6 oz epoxy and paint?
     
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