pontoon size and length

Discussion in 'Boat Design' started by james wolfrey, Sep 13, 2014.

  1. myark
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    myark Senior Member

    It feels a bit watchkeeperish this post owner.
    Rwatson
    If you are going heavy, then the triple hull is the simplest idea such as folding manually the two out side’s pontoons onto the deck seen its light weight, it only needs to be unfolded to 2.m width making it 1.m wide when towed but is still to heavy.
    With my latest design I can have wider unfolded width but structure is .800 folded and allows storage on deck while in folded form and is 40% lighter than my old similar design pictured.
    You have seen something similar what this is and see if you can figure this puzzle.
     

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  2. rwatson
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    rwatson Senior Member

    Its a fun game for sure, this configuration decisions.

    I was thinking about it more this afternoon, and I wondered why the need for a trailer less than 6ft is even necessary, so why even make it foldable.

    I have towed a lot of boat trailers, and they were all over 6 ft wide, without any problems.

    With multihull setup, even with folding, you are adding the problem of fastenings, manhandling at the ramp, and the engineering calculations that go along with it. If you stuck the 2 outrigger hulls on beams, then you have to hassle about slide in, slide on setup, and bending loads on what might be significant weights of outer hulls to complicate it more.

    I have no real expertise in aluminium, which makes a good trailer, and steel is probably not a good choice for something this small for water.

    This is only for a motorcycle, and wont come up very heavy say in plywood. 9mm ply is about 30 kilos a sheet, the size I have played with would come out at say 4 sheets including internal ribs, so thats 120 kilos ( say 260 pounds ).

    I would go for a lift up or tiltable draw bar and steel subframe only because I can weld steel, and aluminium axles are not common. I have investigated those torsion bar suspensions, and they are super expensive. Great if you can afford it though.
     

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  3. myark
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    myark Senior Member

    Are you thinking of making one for your self if so its all bad so far.
     
  4. myark
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    myark Senior Member

    This is a 6' x 4' and hate to go 6' wide and tow behind a bike.
     
  5. rwatson
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    rwatson Senior Member

    The guys got a Harley, so its got grunt.

    The budget is the big question - can he go aluminium and torsion suspension ?
     
  6. myark
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    myark Senior Member

    The welded hinge fixings to fold aluminium structure is no problem also when unfolded the weight is pressing the pontoons into the middle deck so no stress when pinned.
    Fixing ply to heavy frame and suspension let alone a 6' wide width destroys the practicality of the project besides the electrolysis.

    To able to tow with minimum weight and width, to unfold like lifting up and down a swinging garage door while the wheels automatically come out of water, also been able to tow open or shut.
    Insides the pontoons there is storage, also on the middle deck is storage, an out board motor comfortable sites on the back deck as the deck is always in its same position when folded or unfolded.
    This chap also wants to use his Hog to power the pontoon which a Tom Kane pivotal drive is a perfect low cost and reliable system.
    There are many ways to adapt power to prop for example attached is a picture of a gear placed on wheel that can have a chain or belt drive to a redirecting box to a Tom Kane pivotal drive.
    Not sure if a Hog can fit this gear needed.
    I have given the basics idea of the pontoon structure, see if you can work the puzzle out.




    http://www.boatdesign.net/forums/boat-design/japanese-liftable-propellor-shaft-51297-7.html
    The experts say you can not do it, they get very upset and quite abusive .When you have a Pivotal Drive fitted in a trailer boat in practice when the boat is on the trailer it is lifted up automatically by being put on the trailer and when you launch the boat the drive drops down by itself down 20 degrees shaft angle or more.

    When the boat is in the water just start the motor and away you go and you can adjust the depth from the helm if you wish. You do not need a clutch because you can lift the prop up from the water. When you go in shallow water the skeg lifts the drive automatically. With twin rudders that work like a kitchener rudder you do not need reverse as the boat turns in its own length right or left.

    The drive does not need to be locked down as it trailes behind the boat and finds it`s own operating depth. You can use the drive as a surface drive with the suitable prop
    and lock the drive at any depth you choose. It can be used in a Hydroplane if the rules allowed for cornering and speed control and braking.

    If you spent a lot of money you could have all sorts of inovative things like automatic detection of object strike and lifting. The list goes on and on.

    __________________
    tomkane
     

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  7. whitepointer23

    whitepointer23 Previous Member

    Fisherman over here have used barges with fixed wheels and tow hitchs for 50 years in the beach fisheries. A lot are ply and steel. Easy to build a smaller version without trying to make a folding system for no gain. I can only see benefit In a folding barge if it is overwidth or for storage.
     
  8. whitepointer23

    whitepointer23 Previous Member

    As for making drive systems. It makes much more sense to use an outboard for simplicity and reliability.
     
  9. myark
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    myark Senior Member

    Show me one to compare ? it is over width for bike to tow
     
  10. myark
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    myark Senior Member

    This post is about adapting drive system from bike to prop
     
  11. rwatson
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    rwatson Senior Member

    Thats the secret for sure - simple, cheap and effective. Folding is a hassle, as every owner of a demountable catamaran or trimaran will tell you.

    The other big consideration about using a motorcycle engine to propel the barge, is that MCs are air cooled, and you could cook your engine if the airflow is low.
     
  12. myark
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    myark Senior Member

    A 2.m wide trailer towed behind bike with heavy steel frame that rust and old type suspenion with wood that reacts to metal and cheap and heavy.
    Oh my god :eek:
    Back to inside the square


    Its a small bike trailer not a demountable catamaran or trimaran
     
  13. rwatson
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    rwatson Senior Member

    How much does your aluminium 6 x 4 weigh ?


    edit: and by the way, is thew drawbar and axle on your trailer made of aluminium ?
     
  14. myark
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    myark Senior Member

    I am not sure of the weight but lighter than any trailer that size also took two people to lift and place on the back a truck to export to my home in Thailand.
    It’s actually a 2. x 1.2 and with a 100cc motor bike and my two sons and I aboard, it floated in less than 100mm of water, the tail gate is the ramp and the draw bar is made from aluminium with Teflon sleeve and titanium pins.
    This is made so if the bike falls over the trailer is still upright and no damage, also great to lean into corners as the draw bar swivels at any angle.
    The suspension is a titanium torsions bar and arm with titanium axles and titanium hubs with the casings that surround the rubber cord is made from aluminium.
    Yes its expensive suspension and cost $800 but it’s a life time product that the rubber cords are DIY replaced and saves weight especially if man handled or towed with bike.
    I take the wheels of and stand it up right in my bedroom and use it as wardrobe this moment.
    I have used it as a small pool for my sons to swim.
    Anyhow that's not the trailer I would make for floating a Hog as that model is much less weight and a lot narrower when folded and a lot wider when unfolded and a lot less price.
    I have made aluminium torsions suspension axles and hubs and was very light and worked OK but not as good as titanium.
    I can also make from stainless steel and keep the cost very low but it becomes heavy.
    Steel :eek: wood :eek:
     

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  15. rwatson
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    rwatson Senior Member

    yes, a superior solution, but as you say much more expensive.

    You seem to equate wood and fg as a poor substitute, but in reality it can be a very good performing material.
     
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