Advice on Raft/barge/ferry from lumberyard material for occasional 6 mile trip

Discussion in 'Boat Design' started by Randall Brower, Apr 27, 2020.

  1. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Gonzo,

    This is the OP's limitation, why don't you ask him about it?
     
  2. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Randall,

    DogCalvery is right, I'm grumpy and burned out.
    But, you can't get rid of me that easily.

    Can I ask some closed probe questions?
    Are you expecting to insure this raft?
     
  3. Randall Brower
    Joined: Apr 2020
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    Location: Tanana AK

    Randall Brower Junior Member

    Another limitation. Yes we have welders (the device and the human) but at 15 cents per pound steel would get really expensive to ship it by barge. And I cant weld. I even checked into going to welding school but thats like 3 months long. Besides, I want to build it. I want this to be a fun experience/challenge for me, something I can enjoy for the next several years. I don't want pay someone else to build it. Those are a couple of reasons why I never listed steel as an option. If I was going to do that Id just hire a steel fabricator in Fairbanks to build me a boat. We have lots of those. But whats the fun (bragging rights) in that? Any idiot can do that.
     
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  4. gonzo
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    gonzo Senior Member

    I disagree that any idiot can hire a good designer and welder to get a good boat. However, if you want to build a boat, what are your woodworking skills? Building a wooden boat that can take the amount of grounding impact and able to be dragged over the shore is not easy.
     
  5. portacruise
    Joined: Jun 2009
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    portacruise Senior Member

    With $5,000 as the budget, me thinks barrels and dock floats are out of consideration. Logs have been proven to work and would appear to be the cheapest thing, almost free flotation, if you gather them yourself. Drilled holes and high-strength galvanized Bolt together Construction to a top deck of interlocking and intersecting logs (like log cabins?) might be the simplest, while staying cheap. I've read that at least some sections of the river are very hard to navigate because of hourly shifting sand bars and that generally shallow murky water makes it hard to keep from being grounded. So a low draft design (or cheap anti- grounding Wheels?) is probably a consideration?
     
  6. DogCavalry
    Joined: Sep 2019
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    Location: Vancouver bc

    DogCavalry Senior Member

    Gonzo is as grumpy and burned out as Bluebell. But he gets to be, because he also talks to the idiots long after I've blocked them and moved on. I reckon he's raised a couple teenage boys, to be so doggedly determined to bring sense to the world. I don't have his patience.

    I don't mean to suggest that you're one of those idiots Randall. I love your attitude, and the problem you've posed. I'm building my own boat right now, when I could buy an adequate used boat for less.

    But tell us, because it's a critical factor: what's your heaviest load going to be? Empty truck? Loaded F150? Overloaded F350? If a loaded truck, can you unload it to spread the load on the deck, or does it stay loaded.
    And where will you drive on or off? If there's a dock at one end, how high?
     
  7. Tiny Turnip
    Joined: Mar 2008
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    Location: Huddersfield, UK

    Tiny Turnip Senior Member

    Hi Randall - I like your project, and I 'get' what you want to do. I come from the land of cucumber sandwiches too, and frankly, the Yukon river looks terrifying - the nearest we get to that is the Humber estuary. Now, I'm not a naval architect, or an engineer, and it would need engineering, but I am an architect, and could probably knock up some schematic sketches using diaphragm (sheathed or skinned) trusses to build a big floating box in timber and ply. Say 3/4 " ply. It would be the vulnerability to puncture and abrasion that would concern me most, and that would make me want to double skin it, as well as protecting vulnerable edges with tyre or metal. I did some 5 minute very back of an envelope calculations. A 20 ft by 40 ft box, top and bottom, is 25 sheets per skin. If you double skin the bottom, not the top, that's 75 sheets. Depending on structure, there's another 25 sheets or so in the diaphragm trusses. A quick look at Lowes Fairbanks for severe weather sheathing ply (couldn't find marine grade) runs $60 a sheet. Dunno if there's taxes on top of that. Now that's your $5k used up just in ply, before shipping (at 15c/lb, 60lb per sheet, thats upwards of $900 just for the ply) and then there's extra ply for gusset jointing the sheets, loads of framing timber, fixings, adhesive, waterproofing, hardware ... I'd suggest that the big floaty box is a long way above budget. The catamaran hulls might be less materials. But they would need more designing (naval architecting). Hope the guestimates are in the right ball park - haven't checked them.
    Edit: forgot to mention ply thickness. Added assumed 3/4"
     
    Last edited: May 6, 2020
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  8. DogCavalry
    Joined: Sep 2019
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    Location: Vancouver bc

    DogCavalry Senior Member

    So, here's what I've got. I'll start with materials, because that's cost.
    100# of 3" hdg finishing nails.
    10 cases of PL Premium. The daddy tubes, not the mommy tubes.
    1000 square feet of vinyl deck membrane, and contact cement to go with it.
    A metric buttload of elbow grease.
    Bucket of paint on wood preservative. This used to extremely effective, as in sooper dooper poisonous alkaline copper quaternary compounds. Don't know what they put in it these days. Used to paint the end of PT lumber when you cut it.

    And that's it. Sketches to follow.
     
  9. gonzo
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    gonzo Senior Member

    What is the vinyl deck membrane for?
     
  10. Squidly-Diddly
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    Squidly-Diddly Senior Member

    I think its doable at $5000, since the Fairbanks, AK Lowe's seems to have normal prices for stuff like 3/4" plywood.

    I was thinking of a big plywood box, 4' deep and about 40'x20', or maybe two boxes for cat, with 2x framing and bracing. To support heavy truck on deck use a couple 2x12 runners, and to drag out of the water have 2x12 skids. For strength and safety, divide the interior with plywood, and fill sections with big trash bags full of air and tied off.
    If its a cat make it pointy on all four ends, if its a barge make it sloped on both ends.
    For the plywood to framing https://www.lowes.com/pd/Paslode-2-...or-Pneumatic-Framing-Nails-2000-Count/1208893
    All they show at Lowe's is little A35 clips but I'd want some of this, but not sure where I'd want it. https://www.amazon.com/Simpson-Strong-CMST12-12-gauge-Coiled/dp/B001EPSHW8 and some "tico" nails https://www.lowes.com/pd/Fas-n-Tite...el-Exterior-Joist-Hanger-Nails-5-lbs/50423202

    HDG 8d nails might be OK for plywood, but screws better. I'd definitely use semi-malleable (not brittle cast, so they don't break) long screws for framing, as nails will work loose with slightest movement.

    What to waterproof it with? Good question. I guess that depends on how long its going sit in the water, and what AK winters do to what coatings.

    To space or not space the plywood joints? Under stucco, plywood is supposed to have 1/8" gap so if it gets wet and expands it doesn't want to bulge and pop the stucco off. But this isn't stucco, but plywood is likely to get wet.

    Real question is what should the frame of various 2x, 4x or 6x material look like. What would fast and easy and correct for this sort of boat to cover in 3/4" plywood? I'm familiar with building but thats diff set of loads and much of it is about staying in sync with other trades.

    OP says "only" 2' waves but thats still a lot of water weight against a big flat hull loaded with 5 tons.
     
  11. hoytedow
    Joined: Sep 2009
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    hoytedow Wood Butcher

    I am also grumpy but I bottle it up. Saving it for a stroke
    Have you gotten legal advice re: liability etc.?
    I have been building boats for personal use over 5 decades and no sign off by professional nautical architects or engineers, hence none were insurable.
     
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  12. hoytedow
    Joined: Sep 2009
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    Location: North of Cuba

    hoytedow Wood Butcher

    Don't depend upon PL adhesive for the stresses it will experience.
     
  13. hoytedow
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    Location: North of Cuba

    hoytedow Wood Butcher

    It's good stuff within its design limitations.
     
  14. hoytedow
    Joined: Sep 2009
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    Location: North of Cuba

    hoytedow Wood Butcher

    Alaska takes guts. A hat tip.
     
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  15. DogCavalry
    Joined: Sep 2019
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    Location: Vancouver bc

    DogCavalry Senior Member

    Pl is stronger than the wood it glues. If it's not strong enough, the pl is not at fault. Get stronger wood.

    The deck membrane is to single sheet waterproof the hull. An ergonomic textbook I used to have said that a fat chick could apply 3000 psi under her high heel shoe, walking normally. Deck membrane can take that.

    From Lowe's
     
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