Lightweight Canoe

Discussion in 'Fiberglass and Composite Boat Building' started by Bluegoose, Jan 11, 2014.

  1. AndrewK
    Joined: Mar 2007
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    Location: Australia

    AndrewK Senior Member

    Bloogues:- recently I made a 4.6m 15' canoe, simple flat bottom and sides 3 pannel job. But is narrower than what you want at 600mm 2' bottom and 750mm 2'6' at gunwales and no seats, I use 200mm block of PE foam to sit on, would like nice inflatable seats with backrests available in US for $40 but they want $80 to post two to Aust. This weighs 39 lbs and is made with 3.5mm ply sides no glass just resin sealed, the base is 50mm 2' polystirine (24kgm3). Outer bottom laminate is 400gsm double bias and inside is 600gsm, hand laminated.
    I find this schedule robust enough but others would want 2000gsm of glass, its a personal thing. The lighter you want to build the more fragile it becomes.
    I routinley use infusion and foam cores but still chose to use ply and hand laminating for this one due to cost and ease of making, cost was $200.
    Estimate weight of building with 6mm 80kg foam and 400gsm laminates was 30lb.
     
  2. Bluegoose
    Joined: Jan 2014
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    Location: Tennessee

    Bluegoose Junior Member

    With all the rambling I’ve done in the above posts, let me clarify and keep things focused. I’m not dead set on using foam core and fiberglass construction, nor do I have a burning desire just to use the material. I’m really looking for a technique that will allow a reasonably competent person with regular tools and equipment to make a 15’ long x 36” wide “recreational” canoe that ideally weighs 50lbs, or less. (The 50lbs is finished weight: hull, framework, trim, seats, paint, etc…) The simpler the construction method, the better. I ‘m not trying to make it complicated. If there’s no better material than regular plywood, then plywood it is. I’ll make the hull out of plywood and try to keep all other framework to a minimum. Before I start, I wanted to look into other options and building methods to see if it’s possible to get the weight lower than that from using plywood.

    If anyone is interested in the exact type of canoe, it’s called The Townsend, and it’s available at the Jemwatercraft website. It’s your basic stitch-and-glue canoe.

    http://www.jemwatercraft.com/proddetail.php?prod=Townsend15-36

    Thanks again for everyone’s comments and inputs.

    AndrewK: Thanks for giving some very specific info. I just read your post, and I'll have to convert it to imperical numbers to get my mind around it. This forum is cool. It blows my mind to think that I can have a conversation with someone in Australia (from Tennessee) so easily. Hope you're got some good weather down there.
     
  3. AndrewK
    Joined: Mar 2007
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    Location: Australia

    AndrewK Senior Member

    Having a scorching summer here, recently had the highest temperature in Brisbane 46'C ~ 115'F. At the moment having the same temperatures all across the south of the continent and fearing serious bush fires. Some have already started.
     
  4. AndrewK
    Joined: Mar 2007
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    Location: Australia

    AndrewK Senior Member

    Just had a look at the canoe and looks good. I suggest you use 6mm 1/4" ply only for the two bottom panels the rest can be thinner. Can post a photo of mine if you like.
     
  5. redreuben
    Joined: Jan 2009
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    Location: South Lake Western Australia

    redreuben redreuben

  6. redreuben
    Joined: Jan 2009
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    Location: South Lake Western Australia

    redreuben redreuben

  7. Bluegoose
    Joined: Jan 2014
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    Location: Tennessee

    Bluegoose Junior Member

    AndrewK - I'm definitely interested in seeing a picture of your boat. I have to have 5 posts in a forum before I can send someone a private message. This should make my fifth. I'll try and send a private message, so we're not clogging up the thread with stuff specific to just us.
    Sorry you're suffering through a heat wave. We just had some cold weather (down to 0F or -18C) this past week due to a "polar vortex". Go figure.

    Redreuben - thanks for the post. That Eureka boat looks interesting, I'll definitely check out the website closer as time permits. That ultralight boat scares me a little though - 3mm plywood has got to be...flexible...yeah, that's the word. Apparently it works, but I'd be a little skeptical of it. Their "standard" hull boat still comes in a very reasonable weight. I'll check it out.

    Y'all have a great weekend. Time for bed on this side of the world.
     
  8. AndrewK
    Joined: Mar 2007
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    Location: Australia

    AndrewK Senior Member

    The 34lb Eureka looks great.
    One of the advantages of building the base with a thick foam core is that it gives you exceptional stiffnes plus built in buoyancy. Basicaly you have a standup paddle board with topsides.
    Will take some pictures tomorrow and post them.
     
  9. AndrewK
    Joined: Mar 2007
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    Location: Australia

    AndrewK Senior Member

    Here are some pictures, canoe is only resin sealed but will get painted next time I am painting something on the big boat.
     

    Attached Files:

  10. Petros
    Joined: Oct 2007
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    Location: Arlington, WA-USA

    Petros Senior Member

    I have built some 20 or so small boats, kayaks, canoes and small sailing dinghy using skin-on-frame methods. Material costs are typically $100-$200, and typical kayak weights are 20 to 30 lbs. Much lighter and less costly than production kevlar or carbon.

    The best stitch and glue or strip built kayaks of similar size are in the 3 to 40 lb weight and $800-1000 in materials cost.

    It seems to me for both low cost and light weight, the skin-on-frame construction method is very hard to beat. It is most suitable for smaller boats like canoes and kayaks, but that is what you are talking about here.
     
  11. Bluegoose
    Joined: Jan 2014
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    Location: Tennessee

    Bluegoose Junior Member

    AndrewK: that's a nice looking boat. So you made bottom out of 2" polystyrene? That's interesting. I would have never thought to use thick foam like that for the bottom. Once you fiberglassed it I suppose it's durable enough and sturdy enough? Any particular method to the madness of using a lightweight foam bottom? 24kgms is about 1.5 lbs/cu ft. I would think that's kind of lightweight material.

    Also, what's the reasoning for using the lighter fiberglass material (400gsm) on the outside and the heavier material (600gsm) on the inside? I would think you want the heavier material on the outside, but am I missing something? Is there a better reason to put it on the inside?

    I'll try and attach a few pictures of the boat I built a couple of summers ago. Design wise, it's similar to yours. It's 15'6" (4.7m) long and about 33" (0.8m) across the bottom. It's made of 1/4" plywood and epoxied with 6oz/yd (200 gsm) fiberglass inside and out. To me, it feels like a good solid boat, but it's a little heavier than I'd like. It weighs in about 70lbs (32 kilo) when it's fully rigged up. As I said earlier, I'm sure I could make it lighter if I built it again, but you have to start somewhere. It's "brand new" in the pictures. I was trying to decide exactly where to place the seats. The weight wouldn't be unbearable, but I have some really tough spots to carry the canoe through to get to where I need to go.
    Anyway, I'll try and attach the pictures to this post.
     

    Attached Files:

  12. Bluegoose
    Joined: Jan 2014
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    Location: Tennessee

    Bluegoose Junior Member

    Petros: thanks for mentioning the skin on frame option. As I said in a previous post, I'm not stuck on using foam and epoxy. I just assumed a stitch-and-glue design made out of foam and epoxy was the simplest, easiest way of getting the boat I was after. If skin on frame works, I'm certainly open to trying it. (especially if it's cheaper)
    I've been looking at skin of frame canoes on the web, but it's a little tougher to find information on them than it is the stitch-and-glue approach. What method (of skin on frame) do you use? Can you point me to a website or book that you reference?
    I'm going to try and attach a link to the canoe I would love to have if money was no option. It's made by Merrimack and it's called the Osprey. (If the link doesn't work, you can "google" it.)
    http://merrimackcanoes.com/our-canoes/osprey
    Unfortunately, it's out of my price range. But I really like the design. I'm looking for something I can stand up and fish in. I'm mostly fishing creeks and small rivers - no white water. I need something lightweight so I can carry it to some really tough put-in spots. I'll use it mostly solo, but having enough capacity to take along another person would be nice. I think a boat about 14'-15' long and 36"-38" wide, with a mostly flat bottom would be ideal.
    Many of the skin on frame canoes I saw on the internet had what appeared to be a "rounded" bottom hull. I'm assuming it's because it's difficult to get a mostly "flat" bottom when bending the "ribs". Is it possible to get a mostly flat bottom with skin on frame? The rounded bottom canoes (even at 36"-38" wide) don't have the stability (for standing and fishing) of a flat bottom boat. I'm very interested in pursuing the skin of frame concept, I just want to be sure I don't have to change the design of the boat I have in mind to accommodate the method of construction. I'm interested in learning more though.
    Thanks again, if anyone else has comments, I'm definitely open to suggestions.
    P.S. Here's another boat that's very similar to what I'm after. It's the Old Town Guide 147. Much more in my price range, but too heavy (82 lbs).
    http://www.oldtowncanoe.com/canoes/recreation/guide_147/
     
  13. upchurchmr
    Joined: Feb 2011
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    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    Blue goose

    What you referred to as Skin on Frame the Merrimack is not what people talk about.
    That canoe is a complete wood canoe with a canvas skin (old style) or a more modern material covering. Lots of work.

    Skin on frame has significantly less wood, lots less work. It can have the steam bent frames or just frames cut from plywood (the least work).
    Did you ever look at the Dave Gentry canoe?
     
  14. upchurchmr
    Joined: Feb 2011
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    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member


  15. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    Ballistic nylon, stretched over a wooden frame, is the ultimate in lightness, with great toughness.

    Check this out

     
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