motorized home made raft

Discussion in 'Boat Design' started by Dabney111, Mar 24, 2014.

  1. Dabney111
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    Dabney111 Dabney111

    Hello, is there anyone out there with some actual experience in building a motorized home made raft using 55 gallon plastic barrels for floatation and approximately 8 ft x 20 ft in size and which would be suitable for a 300 mile or more trip on a major river in the U.S.? I've been reading on the internet all day and have mostly found smaller non motorized rafts that would not be able to handle a river situation. I have a 15 HP outboard "in hand" and access to large quantities of suitable barrels. I have thousands of miles of single and twin engine gas and diesel vessel experience on most major rivers in the states - but now, as an old "senior" I am looking for a "final" river trip with some adventure. If you have not attempted this, could direct me to a site or other location for instructions on the framing necessary for this project? I would appreciate it.
    dabney111
     
  2. Westfield 11
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    Westfield 11 Senior Member

    You might try a search for floating docks as opposed to a raft per se. I have seen a few in the PNW made from the blue barrels you describe and perhaps their construction could be adapted for your use. The platforms for floating homes might be another google search as well.
     
  3. rasorinc
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    rasorinc Senior Member

    If you are going up river with 14 barrels lashed together with wood overlapping sides and wood separation beams, with a wood deck and side rails I think your asking way to much for your 15hp engine to do. Just my 2 bits. Also, on a river with barge traffic
    you need some speed to stay out of the way. They brake for no one.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Up river seems like the wrong direction for this idea, it will be lucky to exceed 4 knots through the water.
     
  5. Dabney111
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    Dabney111 Dabney111

    Down river aways

    Thanks for the reply. I will always be going down river and will have an AIS transponder onboard along with marine radio contact with all on coming traffic.
     
  6. Dabney111
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    Dabney111 Dabney111

    Westwood 11, thank you. I will try those suggestions.
     
  7. viking north
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    viking north VINLAND

    45gal. plastic drums set up as a pontoon platform 20ft. long by 8 ft wide has far too much positive buoyancy. A platform raft this size would be highly subject to rolling over. As a matter of fact 45 gal. plastic drums have so much positive buoyancy as pontoons they need separation (beam) and weight to reduce extreme reaction to wave activity. When we use them to build pontoons for floating docks they are partially filled with water to reduce buoyancy otherwise they are so active they tear away from the gangplanks or tear the gangplanks away from the land dock connection. I am building a mooring anchor setting twin pontoon raft from 20gal. drums strapped into construction catwalks. I can't comment on it's performance as it is about 3 months away from launch but I expect it will be much better than using 45gal drums. ---
     
  8. Dabney111
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    Dabney111 Dabney111

    Too much buoyancy

    Very interesting and useful comment. I would like the top of the deck to be about 12 inches above the water line. If I know the approximate weight of the cargo and wood framing materials I thought I would be able determine the number of the barrels needed.
    Would this problem be one of just determining displacement?
    I think I can handle that as well as making "field" adjustments for the heavier areas around the transom, etc. I might also be able to make adjustments by partially rippling certain barrels. While flotation/displacement is an important and critical consideration, I could also use some input on framing and strapping. The rivers I will be floating are wide and slow moving with plenty of depth for my purposes, but I do need a stable well built platform to handle occasional heavy wakes or weather. Of course I would use screws and bolts as appropriate, and no nails! The floatation issue is very valid and will be addresses. But has anyone out there actually built a raft near this size and used it for my stated purpose? I know what I' m suggesting is not the best way to take a trip down the river -and But I be already done it the other ways!!
     
  9. Mr Efficiency
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    Mr Efficiency Senior Member

    Well, if there is too much bouyancy, you need less barrels. It obviously depends on what weight has to be supported. Tailor it to how much elevation you want to maintain above water, but bear in mind that a cylindrical barrel laying on its side requires progressively less additional weight for another inch of submersion, if more than half submerged.
     
  10. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Well, it spring at last. At least it seems this sort of thing pops up as soon as winter cracks and the cabin fever ravaged, consider duct taping barrels together for a good time. Try beer, it's cheaper . . .

    I'm not trying to be coy, but attempting to short cut the very thing that keeps your socks dry seems, well ill conceived at the very least. Making a set of plywood pontoons, will likely prove much more reliable, probably cheaper and certainly will perform considerably better with much less fuel consumption too.
     
  11. Mr Efficiency
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    Mr Efficiency Senior Member

    "Second childhood" expeditions must be undertaken with the at-hand materials used in childhood !
     
  12. PAR
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    PAR Yacht Designer/Builder

    Maybe one of those juice in a box things, that come with their own straw?

    Each year we get a few of these. I've always wondered why someone would consider a cobbled together hull or set of hulls, from questionable materials, requiring excessive attachment considerations, etc., when just building or buying a well used, but nearly spent hull for a couple of hundred, gets the engineering done up front, without duct tape and a dozen barrels. There's a 21' center console not a mile from me. The trailer is worth the $1,000 price. Yeah, the engine is shot, the floor on the soft side and it likely needs stringers and a transom too, but it's a whole lot easier to play with, then figuring out how to join a bunch of barrels.
     
  13. portacruise
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    portacruise Senior Member

    Some ideas: http://www.angelfire.com/ultra/edaskew/genbarge.html

    Porta

     
  14. Dabney111
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    Dabney111 Dabney111

    Rafting

    Par, You are most likely living a stale life, with no sense of adventure left in you. The whole idea is just to see if it can be done, perhaps better. I've already experienced the journey in the comfort of a small 50 foot yacht and in doing so passed by those sailors on their home made vessels of all types along the Mississippi, Ohio, Tennessee, Arkansas and other rivers. I came to look upon them as the ones really living life to its fullest. Not everyone goes thru life in the missionary position, but chooses adventure instead. Next time you see some "jerks" struggling along in their vessel, ask yourself who is engaged in the greater adventure -in you, or them.
     

  15. Dabney111
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    Dabney111 Dabney111

    Raft bouyancy

    Mr. Efficiency, thank you for the useful comments. I am thinking that by carefully positioning the barrels I may be able to add water ballast as needed once the vessel is launched an loaded. Otherwise it may be possible to carry ballast in a couple of "extra" barrels I will be carrying, secured, on deck, or just transferring weight, such as the small generator and spare 25 HP engine.
     
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