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. bajansailor
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    bajansailor Marine Surveyor

    If you try to 'drive on' a Chevy Suburban on to a 20' x 10' barge, you will only have 1' all around - not much margin for error if you overshoot......
    Be aware also that the raft will sink down considerably as the weight of the vehicle first lands on the edge of the raft, and it will get a bit 'skittish'.
    I have not tried to do any calculations re stability, but a simple 'seat of the pants' estimate would suggest (to me) that for a barge built with drums for floatation, you would want a beam of at least 17', and a length of at least 35' (this could be in a catamaran form) to carry this vehicle - to be safe I would even be looking at 40' x 20' - which is the rough size proposed in your original post.

    For reference, here is a neat little cat barge loading and unloading a twin cab pick up -
     
  2. BlueBell
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    BlueBell Ahhhhh...

    I drove a 42" SeaTruck (12' beam) with an overloaded Suburban on it once in 2' seas and it was borderline.
    Twin screw, I/O, good power.
    Can't you chain or bolt together a seasonal catamaran raft?
    Perhaps build a frame work that would hold lots of logs, seasonally.
     
  3. gonzo
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    gonzo Senior Member

    He needs a junkyard dog to guard the logs.:rolleyes:
     
  4. BlueBell
    Joined: May 2017
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    BlueBell Ahhhhh...

    Randall,

    Have you considered buying a landing barge and making a business out of transporting?
    You mentioned it was expensive. Can you do it for less?
    That would be the way to go for a loaded Suburban+

    Otherwise, build a 20' x 40' bomb proof frame and fill it with logs every spring.
    Lowes should have long bolts (through bolts not lag, or all-thread), long 2 x 12's 4x4's 6x6's.
    If not logs, do they carry those 45 gallon drums you love?
    But you're going to need a lot of lumber and supplies to do this.
    And, a sound design, one that can be dragged by the "bulldozer" twice a year.

    Logs held with chains and/or cables, come-alongs, and a sound design/approach would be my first instinct.
    Are you really sure you can improve on the natives way?
    I'm going to check out that video you spoke of.

    Cheers

    Edit: No plywood.
     
  5. Randall Brower
    Joined: Apr 2020
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    Randall Brower Junior Member

    Clearwaterdocks.com in Anchorage.
     
  6. Randall Brower
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    Randall Brower Junior Member

    Thanks for those suggestions. Landing Craft is over 100k and I have no interest in owning another business. I'm semi-retired and my other obligations are too important. I agree with your point on adopting what the natives have been doing for years and just strengthen it for storing it.
     
  7. alan craig
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    alan craig Senior Member

    I like this thread. Coming from the land of cucumber sandwiches and sometimes a bit frosty in the winter, it's astounding to think of breaking ice that can take out trees.
     
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  8. Blueknarr
    Joined: Aug 2017
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    Location: Colorado

    Blueknarr Senior Member

    Alan
    The break up of North bound rivers is spectacular. I spent a summer in Ft Mc Murray Alberta. Not as far north as the Yukon, but still pretty high latitude. I asked a local why the bridge was built do high over the river. He pointed out the dents in the bottom of it. There are no buildings within a quarter mile of the river for the same reason. Airborne ice chunks weighing tons.
    unnamed.jpg
     
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  9. DogCavalry
    Joined: Sep 2019
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    DogCavalry Senior Member

    Fantastic thread! I'm entranced by the idea of a Lowes only barge. Let's set this up as a dedicated thread, so it doesn't disappear when our new comrade Randall's problem is solved.

    Some thoughts here:
    No need for terribly expensive 2x12 lumber. PL premium is much stronger than wood. Glue and screw laminated assemblies to the size you want.
    Welded vinyl deck membrane is tough, wear resistance, and waterproof. It will let your deck survive vehicles driving on it.

    Take a look at a truss joist. They are made from trash and offcuts is a plant. Cheap and super strong. If the inside of your big-*** box if fully triangulated like that, it will survive your point loading.

    No I'm remembering... Did this sort of thing as a combat engineer. Check out ribbon bridge.

    If you use that prefab system, don't make it catamaran like. The trusses in those images won't survive the uneven loading. It will have to be significantly oversized to not roll over and dump your precious truck.

    Stream of consciousness stuff now, but I've got it.
     
    Last edited: May 2, 2020
  10. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Google up our local news and look at the footage of the Clearwater and Athabasca Rivers running near Fort McMurray two days ago.
    It looks like a glacier in fast motion!

    EDIT: This will get you started Fort McMurray floods force 15,000 to flee; Premier Kenney pledges more police, flood mitigation supplies https://www.fortmcmurraytoday.com/news/local-news/fort-mcmurray-floods-force-15000-to-flee-premier-kenney-pledges-more-police-flood-mitigation-supplies
     
    Last edited: May 2, 2020
  11. Squidly-Diddly
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    Squidly-Diddly Senior Member

    What Lowe's lumber is gonna be cheaper (and engineerable, like a general set of plans others could use) than 2x lumber (and plywood)?

    I'm thinking a cat or tri, or quad, would be the way to go, for ease of handling the pieces, hauling out, etc, mostly in the out of the water handling where smaller pieces will be much lighter and lower stressed. See my gallery for modular general purpose (non-wood) cat concept.
     
  12. gonzo
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    gonzo Senior Member

    I think the problem to solve is not one of design and materials. If the locals take the logs for firewood every year, they will take the Lowe's lumber for building houses every year too.
     
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  13. DogCavalry
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    DogCavalry Senior Member

    So yes. Using the limitations stated
    Lol! Yes, that might be a downside.

    SquiddlyDiddly, I was unclear, because I was excitedly thumb typing while grouting a shower floor. I just meant that generally it's cheaper to laminate a large truss from smaller pieces than larger pieces. A 2x12 costs more than 3 times as much as a 2x4. And that is even more true of long lengths.
     
  14. Blueknarr
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    Blueknarr Senior Member

    55gal drums in a steal matrix. Although one would have to replace the play decking after the annual native raiding party.
     
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  15. Squidly-Diddly
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    Squidly-Diddly Senior Member

    per board foot or my personal "true board foot" calcs its nearly equal. 11.5/3.5 VS $27.46/$8.22
    https://www.lowes.com/pd/Top-Choice...-1-562-in-x-11-5-in-x-16-ft-Actual/1000009796
    https://www.lowes.com/pd/Top-Choice...1-562-in-x-3-562-in-x-16-ft-Actual/1000009768

    I used to a "California Framer" wood frame carpenter, but now I just do a bit of metal stud framing. I've noticed that even the thinnest gauge metal stud framing holds up pretty darn well even when exposed to salt water spray for years, and that metal stud system has several properties that might be advantageous in OP's requested type of build, as well as recent low-cost shanty-boat thread.
     
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