Are wooden pirogues safe and sturdy?

Discussion in 'Wooden Boat Building and Restoration' started by mmelnick, Jan 11, 2011.

  1. mmelnick
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    mmelnick Junior Member

    OK, good to know!

    I have access to an electric 2 1/2 HP motor, so I think I'll build it around that idea then.

    Thanks for all the input. I thought that 2 1/2 HP would be extremely underpowered for a 12-14' long canoe type boat. That just shows how new I am to all of this.
     
  2. mmelnick
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    mmelnick Junior Member

    Also, wouldn't a flat bottom design with a slight curve to the bottom where it meets the bow plain fairly well?

    Not that I want a race boat. I just have access to several sizes of motors thst I can borrow for a day trip or 2.
     
  3. PAR
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    PAR Yacht Designer/Builder

    Mmelneck, you're assumptions are not based in the experience and understanding of the several disciplines necessary to make them reasonable.

    Stick with the plans.

    Cases in point:

    Plywood is pound for pound stronger then steel. Typical 'glass boats aren't even close. Plywood in sheet form, laying on a pallet is very flexible, as it should be. Once cut to dimension, glued and screwed to position, it's stiff, and strong.

    Your desire to use a 2x2 along the chine, then tape the seam is not a compatible set of methods. Pick one Mmelneck, they don't mix well. By this I mean if it's a taped seam build, then stick with that method. If it's a plank on frame build, then do that.

    Re-sizing pieces and attempting to re-engineer structural elements are the biggest problems most novices run into. They think they're making things stronger, when in fact, they are burdening the boat with high point loading, stress risers and excessive weight. Transoms have been standardized for several decades now, based on outboard HP, anticipated bottom loading and how much strain transfer they can expect from the build method employed. If there's no expectation of an outboard, then the transom is generally the same scantlings as the top side planking. 1 to 5 HP outboards are typically 3/4", 5 to 15 HP 1" - 1.25", 15 to 30 HP 1.5 - 2". A bateau (apparently what you're building) with a 8-9 HP outboard will be uncontrollable possibly unstable too (yep, that's right, flopping over and dumping it's human contents) at most throttle settings, consider a much smaller outboard, like a 2 HP.

    General engineering principles, will force you to reinforce the gunwale area. It's the upper portion (flange) of the "beam", particularly in an open boat. Reconsider your assessment of this area.

    In short, there are (hundreds) free and low cost plans available for these types of boats. Do avail yourself of them, if for no other reason then to save some serious head scratching time or more importantly an embarrassing day at the launch ramp for the first time. If you can't find one you like, drop me an email, I have a few as well.
     
  4. mmelnick
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    mmelnick Junior Member

    OK thanks, I had read about a dozen write ups and gone over the plans for several different designs. I was planning on taking information from several of them and just making my own design.

    After reading your previous post I don't think that's such a great idea.

    Which method would make for a more rigid/sturdy hull then? Taped seam or plank on frame? Or does it not really matter?

    I'm still open to different designs. I've been planning on doing a 2 sheet pirogue style boat, but aside from that I haven't made any final decisions.
     
  5. Submarine Tom

    Submarine Tom Previous Member

    Don't rule out an inboard electric.

    Search "Jeremy Harris"(SP?) here.

    -Tom
     
  6. mmelnick
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    mmelnick Junior Member

    An inboard motor wouldn't work. I need something that I can take off when I'm on the river or in shallow swampy areas. Plus I already have access to a 2 1/2 HP electric trolling motor that I can use for free.

    I'll probably be using a paddle most of the time. But it would be nice to build it with the idea in mind so I can use a small motor if needed.

    If anyone has any suggestions on a certain plan that sounds like it would fit my needs that would be great. I was leaning towards the one at bateau.com, but that one doesn't have a transom. That's why I was going to kind of design my own.

    Here's the link:
    http://www.bateau2.com/free/ccanoeUS.PDF
    [​IMG]

    Is there a plan for a similar boat but with a transom of some sort?
     
  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Jacques' done a good job with that two sheet canoe. A 2.5 HP electric trolling motor will over power this boat unless quite heavily loaded. To move the 13' Bateau canoe, you'd need only a very small trolling motor (which can be side mounted on a canoe), say 25 pounds of thrust (about 1/4 to 1/3 HP). Unless the 2.5 HP trolling motor is on of those fancy German jobs, then I wouldn't believe it's HP figures. 2.5 HP converted to pounds of thrust (roughly) will be in the 190 pound range and they don't make them that big and if they did, it would most surely be 24 VDC or 36 VDC, not the 12 VDC I'm sure you'll want to use.

    Pick up the "Nice Canoe 16" from Bateau of the same designer. It's big enough to actually carry a load, especially a few car batteries for your trolling motor. If you want, you can lop off the *** end a bit and make a little transom. A trolling motor mount isn't very big so the canoe will be 15' will be fine and a 1/2" piece of plywood is also fine for the transom. The plans are 10 bucks, so a pretty good deal.

    This is a taped seam build and a light, strong canoe. It's still a canoe and a lightly built boat, so don't expect it to be a jon boat.

    Both can make a strong hull, but the taped seam method will usually produce a lighter hull.

    Most folks get along with the idea of 2x4's and 1x2's and cutting plywood and screwing stuff together. This is a well proven method, but if you want to lift a boat over your head, to put it on the top of the roof rack, well . . . Taped seam builds can be light, because usually there aren't any 2x4 frames and stuff, but the build requires you play with goo (epoxy) and fabrics ('glass) and this can put off some folks. It's not hard, but it is different. The Bateau site has several videos of how to get things done, so you'll do well with one of their designs as far as instruction.

    The real questions that should be asked are what do you plan on doing with this boat? Will it be car topped? How big is that trolling motor (make & model?)? Where will you use it and the general conditions you can expect to meet when you're underway? What skills do you bring to the table and how big a person are you physically?
     
  8. mmelnick
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    mmelnick Junior Member

    Thanks, I'll look into the "Nice Canoe 16". It looks like the only difference is that I'll need another sheet of plywood and it's a little bit longer.

    What's the beam width on that thing? I can't seem to find it on thier website unless I pay for the plans first.

    80% of the time I'm going to be using it to fish small calm high mountain lakes. These lakes usually have a smooth glass like surface. I may occasionally take it on a large lake with 4-6" waves in a high wind.

    I wuld like a boat that is fast (with the trolling motor or paddling by hand). I don't really care about turning radius so much as speed. From my research I've found that a long skinny boat would do best.

    But I will also take it on the river once in a while. The stretch of the Colorado River that I'll be running with it has a few small rapids (8-10" high at the most). But nothing that any average canoe couldn't handle. It also has some very shallow spots. At times it gets to be as shallow as 4-5". That's what attracted me to the flat bottom design of a pirogue. That and the fact that they are so easy to build.


    I weigh about 180, and will probably only plan on taking one other person with me at a time. Most times that will be a much smaller someone weighing around 140, so I'd be carrying an average load of less than 400 lbs. But I'd say that with 2 guys and a little bit of gear I'd never need to carry any more weight than 500 lbs.

    BTW I will only use the motor sometimes. For 75% of the trips I'll probably just paddle.
     
  9. tinkz
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    tinkz New Member

    when buying luan here, theres single core with veneer skins (yuck), and the other better stuff with 6-7 laminates, all same price. been couple years ago now, I built a stretched 10-1/2 ft skiff from hannu's boatyard site was great little car-topper, only weighed about 75 lbs. very easy for 2 people to handle from car top to water and back.

    small 7/8" inside chine logs, taped seams. with gunwales, corner braces, seat stringers, a couple runners down the bottom, and fully enclosed seat boxes for floatation, it came up being very strong and rigid.
    for building something little, I recommend hannu's boatyard site, theres a LOT of photo's and construction tips there for building small boats. plans are free there too.
     
  10. mmelnick
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    mmelnick Junior Member

    This looks to be the only boat on that site that woudl fit my needs:

    http://koti.kapsi.fi/hvartial/scull1/scull1.htm

    And it looks mroe complicated to build since it's not a flat bottom design.

    But thanks for the link!



    I should also mention that I need something that can be considered some sort of a canoe or kayak.

    In Colorado I don't have to pay to register canoes or kayaks, so that would save me an annual registration fee for a boat that only has a build cost of about a year and a halfs worth of the minimum annual fee.
     
  11. tinkz
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    tinkz New Member

    http://www.simplicityboats.com/summerbreezeduckworks.html

    probably the best usage of 2 sheets I've seen (minus transom), for something small,
    and who says it has to be built for sailing?

    -the down and dirty of it..
    by straightening the floor from midpoint aft (maybe 2" narrower at transom total)
    the rocker in the bottom will about disappear (you can test with cardboard modeling)
    you'll come up with a near 12' skiff that you can slap 5-8 hp onto. 1 sheet 3/8 for bottom and a sheet of 1/4 for sides, another sheet for seatboxes, and about 1/2 sheet of 1/2" for doubling up a transom and motor pad, corner braces etc.

    transom at floor 40" wide leaves 4" each side for a 48" wide transom top, the 16" height layed back the normal 15 degrees gives you about standard 15" short-shaft height.
    hannu's 10.5' skiff was great BUT, too narrow a floor to plane, and a little too light for anything real power. many people were surprised how fast it moved with a little electric trolling motor. nice thing about simple skiffs, theyre really not rocket science at all.
    a couple 3 bottom runners that floor will feel really solid, and put any pounding stresses into the seat bulkheads.

    a flatbottom anything isnt good in rough water, and you sure dont want to turn quickly when running fast, they might grab and flip (roll). on smooth stuff theyre pretty fast!

    if youre looking to build something for electric or a small outboard, those are the 2 sites I'd look to for the freebie plans and instructions to play and tinker with. I'm kinda under the impression you want something to get out in that isnt going to be too heavy for 2 to handle, that'll go electric or small gas at whim, or maybe load both. battery all the way forward for weight, with heavy gage wire run on back for the trolling motor, or mount a troller up front and let the passenger deal with the hassle? its pretty easy to flip a minn kota trolling motor control head 180 degrees, its just 1 bolt.

    another I like for simple is http://www.duckworksbbs.com/plans/storer/punt/index.htm
    it could be built to fit in the back of a pickup easy enough. pretty much the same story with the seat bulkheads/boxes and bottom stringers making something light and strong.
     
  12. tinkz
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    tinkz New Member

  13. mmelnick
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    mmelnick Junior Member

    To be honest I was thinking of jsut "winging it" until this thread changed my mind.

    I was planning on getting 2 sheets of plywood. Cutting a couple 11" wide strips off of each and then scarfing them together to form each side of the boat.

    Then cutting an angle at each end for the bow and stern and holding them together at the bow/stern with some zip ties (until I go the bottom cut and started in with the epoxy).

    Then spreading the beam to whatever width seems to work and marking the other pieces of plywood to make the bottom.

    Then after a few coats of epoxy and some glass strips I woudl be done.

    Maybe a boxed in seat or 2 for extra flotation and that's it.


    But PAR pretty much changed my mind on doing that. I do need to stick with something that is considered a canoe to save on registration fees though. Then "nice canoe 16" looks good though. Or I might just go with the free plan for a slightly smaller canoe.
     
  14. PAR
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    PAR Yacht Designer/Builder

    In most states, the moment you put a motor on it, she then becomes a powerboat that needs to be registered.
     

  15. mmelnick
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    mmelnick Junior Member

    Right, and that's true here, but as stated before, I'll be mostly paddling. I would just like to built it so that I CAN put a motor on it if need be.


    Also, would I run into any major problems if I just built it as described in post #28?

    With straight cuts for the sides, and then placing that on top of the leftover plywood and tracing to make the bottom?

    If that won't work I think I'll go with the batteau plans.


    And thanks for all the advice so far! Although we've gotten pretty far off of the origional topic by now.
     
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