One man pram/sampan/canoe/thingy

Discussion in 'Boat Design' started by vectorges, Oct 30, 2011.

  1. vectorges
    Joined: Sep 2003
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    vectorges New Member

    I inherited two side panels for a 2 foot skiff at a boat building contest. I have a half-baked idea about building a one man paddling (sometimes sailing) boat for use in the local calm rivers and lake. My thought was to build a "three board boat" with trapezoidal ransoms (both front and aft) and a mid flare to give it some rocker. But I can't find anything like my idea. The worst case is to start clamping the sides down and torturing the plywood until I get a shape I like. But that is a lot of trial and error.

    Does my idea sound like anything anyone else has seen?


    Thanx
    George
    Conway, SC
     
  2. Tiny Turnip
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    Tiny Turnip Senior Member

  3. river runner
    Joined: Jul 2011
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    river runner baker

    I've considered making a cheap dory by cutting out the sides from plywood, "sewing" the ends together, speading the panels with sticks (not as easy as it sounds) and laying another sheet of plwood over the bottom, tracing around the side edges, and cutting out the bottom. The tricky part is getting the side panels the right shape. A cheap CAD program like Prochine would help. You could draw the boat on CAD and develop the panels and this would show you what shape the side panels need to be. You could then either print out offsets or try to approximate the shape with a batten and pencil. Two transoms make it a bit trickier, but I think you could still use a similar process.
     
  4. troy2000
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    troy2000 Senior Member

    You'd be surprised how much shape you can get just using straight boards. The sides of this boat started life as plain old 1x12 pine. I ran them through a planer to thin them down, but left them straight from end to end.
     

    Attached Files:

  5. lewisboats
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    lewisboats Obsessed Member

    Your typical cajun Pirogue normally has straight plank sides (nowadays mostly from plywood) and they can come up with some decent rocker. Tombstone transoms might actually be detrimental because they put the sides at an angle to start with, so spreading the shear won't pull up the ends as much...unless you go really wide.
     
  6. lewisboats
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    lewisboats Obsessed Member

    I take that back...this came out OK.

    13" sides (vertical measurement, 13.5" panels)
    12' long
    34" beam at the shear (not including wales or rubrails)
    28.5+" at the waterline
    215lbs displacement draws 3"

    [​IMG]

    [​IMG]
     
  7. troy2000
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    troy2000 Senior Member

    My little Blue Rose is a kissing cousin to pirogues. I started out years ago building a traditional double-ended Caddo lake bateau, and modified it a little each time I built one. Her transom is too wide to qualify as a tombstone, but I still had no problem getting a decent rocker by flaring the sides.

    This is the fourth boat I've built in this style over the years, and I think I pretty much nailed it this time. For example, my earlier versions tracked according to which way they were heeled: if I leaned left, the boat wanted to turn right. Blue Rose tracks straight, even when she's heeled until the gunwale is almost underwater.
     
  8. lewisboats
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    lewisboats Obsessed Member

    You might consider a Bolger Teal...doesn't have the trap ends but as for the rest... a decent 1 person boat.
     
  9. lewisboats
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    Location: Iowa

    lewisboats Obsessed Member

    Going with more flare, more angle on the ends and more rocker we get this...

    [​IMG]

    [​IMG]

    I don't think you would want to go more than that though...you would end up with tracking difficulties etc. As it is... this one would need to be ballasted down more to get it deeper into the water for stability. At the waterline shown you would need 255 lbs overall with the cg in the middle. You're also looking at increased windage at the ends. The waterline is shorter too.
     

  10. messabout
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    messabout Senior Member

    Lewisboats drawings look almost like the drawings for O'briens Six Hour Canoe. There have been a whole bunch of Six Hours built by persons of varying experience, including school kids. Building a boat could not be much easier. Two sheets of ply makes a 15' 6" double ender that probabbly works well enough. It would be easy enough to build this kind of boat in six hours as the name suggests. (But!, finishing will take several times longer than that.)

    I have not built a full sized 6HR but I did build a one eighth scale model. It is kinda' neat looking but does not perform as well as some of my more complex models of the same size.

    The straight factory edge of the ply makes the side plank sheer line (no cutting) . Rocker can be tinkered suitably by putting a small concave curve in the bottom of that plank. Use some poster board and tape to make a scale model mockup. It's a fun exercise if you are into that kind of thing. You need only one mid frame to act as a spreader.
     
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