How Succesful was you lightweight attempt?

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Moonman
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How Succesful was you lightweight attempt?

Post by Moonman »

Hi Guys,

I was just contemplating some techniques to lighten up my next canoe project. On paper, I think I can build a 16 footter at around 38-39 pounds using 3/16 strips and lighter trim.

I'd love to hear any thoughts any of you may have as to how successful you were at building a lighter boat on your 2nd third or 10th boat.

Cheers,

Moonman.
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Bryan Hansel
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Post by Bryan Hansel »

Jay Morrison's article, which you may have seen before, is at this link: http://www.nessmuking.com/lightjaycanoe.htm He's paddled his light boats on some big trips. I've built with 3/16" and 1/8" strips. My guess is that you can easily achieve your desired weight.
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Moonman
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Post by Moonman »

Hi Brian,

I read about a lot of guys using 3/16" strips and only a few using 1/8". How stiff was your hull with the 1/8" strips and what weight fibreglass did you use?

Multiple layers, doubled on the football?

Thanks,

Moonman.
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Glen Smith
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Post by Glen Smith »

My first boat was a 15 foot Hiawatha canoe with hardwood trim and it tips the scales at 45 pounds. I didn't know anything about weight-saving at the time.

My latest boats are built with 3/16" strips. One of them, a 12 foot canoe with 4 ounce cloth (one layer in & out) and hardwood trim weighs 29 pounds. A 13 foot kayak with 6 ounce cloth weighs 25 pounds.

You goal is realistic if you carefully select the trim lumber, use 3/16" strips, use 6 ounce cloth with an extra layer on the football inside and out. But you have to squeegee off any excess epoxy.
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Jim Dodd
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Post by Jim Dodd »

I've always felt that lightening a hull was great, so long as you did'nt sacrifice durability!
A friend who had built a tandem, and taken it to the BWCA, ended up duct taping it to limp back!
Why spend 200 hundred hours on a hull, and have it break down in half of that time in use?
A fix and repair boat, is not a good venture!
Jim
Keep your paddle wet and your seat dry!
Rick
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Post by Rick »

I agree that durability is an issue. I'd want to have some confidence that the boat will last, and could survive some run-ins with rocks, or being beached roughly, or be able to take mild whitewater, or not flex excessively in waves... and on and on.

I tried to keep the Huron below 50 pounds, but with the reinforcement and tougher woods I felt were necessary, 53 pounds was the final result. I'm larger and heavier than LightJay, and pack heavier loads, so my canoes need to be built more heavily for greater capacity.

I'm happy with the way the Huron turned out, if I were to build a lighter canoe, it'd probably be with the lightest woods possible, reinforced with fiberglass... anyway, keep us posted on what your findings are, and good luck with your project!
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Erik, Belgium
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Post by Erik, Belgium »

Correct Jim.

My 17"6' (5.50m) Winisk Canoe was done with normal size 1/4" cedar strips, using black walnut for gunwales and normal size decks, cherry for seats and twarths, and wenge inlay in the bottom. Normal 6oz glass, 2 fill coats ... So, nothing special to keep down the weight. It came out weighing 23 kg, and that is very acceptable to me.

What I do is, I keep to the good practices of canoebuilding and keep epoxy to a MINIMUM(proper layout aso, good squeegeeing, but no excess epoxy). Also I didn't use any hardware/metal in my Winisk, and that 's a weightsaver as well.

I really think that anything you sacrifice in weightsaving, will come back to you on the water (i.e. loaded with gear for a x-day trip hitting something in the water) one day. So I stay close to the rules and let 's be honest: 23 kg is pretty acceptable for a 5.50m canoe.

Erik, Belgium.
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Jim Dodd
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Post by Jim Dodd »

I think using "peel-ply" might be a valid weight saver, without sacrificing durability!

I know a lot of builders don't build floatation chambers, I would'nt build one without them!

Another trick, is to build without a full length inwhale. The ones I've seen have the inwhale in the mid section, just enough to support the seat and thwart in a solo canoe.

Good luck!
Jim
Keep your paddle wet and your seat dry!
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Bryan Hansel
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Post by Bryan Hansel »

3/16" is no problem and actually just as strong as 1/4" according to some tests run by the Goougeon Brothers and published in their building book.

My 1/8" hull was very stiff, because I used three layers of 3.something ounce satin weave glass, which used very little epoxy. I was a little surprised and if the canoe was in the Northland, I wouldn't hesitate to use it on a BWCA trips. I have no questions of its durability.

Cheers,
Bryan
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Jim Dodd
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Post by Jim Dodd »

Hi Brian
I don't doubt that your 1/8in hull is adequate!
In fact I thought of trying it myself different times.
Did you use a 12in spacing on the forms?
Also how did you sand it?
No need to bead ands cove either!
Thanks!!
Jim
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Bryan Hansel
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Post by Bryan Hansel »

The spacing actually wasn't 12" if I remember right. I'll have to pull out the plans. Anyway, it was close to that. And I'd highly recommend 12" spacing, because the strips were very challenging in some places.

Sanding was very difficult. I tried to lay the strips up so that the required sanding would be minimal, but in places I ended up sanding through the hull and had to fill in those holes with new strips.

I actually tried to bead and cove, but that didn't work. So I hand beveled the edges.

I think the key was the three layers of that satin weave glass. It added surprising stiffness to the boat for very little weight. If it wasn't more expensive, I might have used that lay-up on more boats.

After saying all this, I don't think I'll do a 1/8" boat again, because it was a lot of extra work. Still, it was fun to build and a worth while project. In the end, my canoe was a little heavy, because I used ash gunwales and a bunch of other heavy stuff. I'm attaching pictures, please, forgive the quality. A very very old digital camera was used for them in the way back.

Image
Image
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Jim Dodd
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Post by Jim Dodd »

Thanks Bryan For your insight!
Years ago I saw a stip built canoe, where the builder used what appeared to be thin veneer, for the wood core!
The strips were 4 or 5in wide, and appeared to be molded to a form before glassing.
I'd like to find that boat again, and check the weight.
Thanks again Bryan!
Jim
Keep your paddle wet and your seat dry!
AlanWS
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Post by AlanWS »

This guy has some tips for lightweight canoe construction, and offers detailed manuals taylored to specific designs: http://www.laughingloon.com/shop.tips.html

Here are a few other thoughts:
When you select your stock for cutting strips, search through the lumber for lighter weight boards. Make sure strips fit tightly, since epoxy is more dense than wood: gaps that fill with epoxy are not strength problems, but they add weight. When you glass, try to make sure to use the minimum epoxy that fills the cloth.

Some time ago, there was someone, I think on this forum, who posted under the name "Dr. Dichroic". He made an electric glass-bottomed boat (not a canoe) that he glassed without any fill coats by covering the epoxy-wet glass with a plastic (PETG) film, and rolling it out smooth. After cure, he peeled off the film to give a very smooth surface. (I can no longer find his website.) While this technique is better applied to the simple curves of a stitch and glue boat than to the compound curves of a strip built one, it seems to me an excellent way to minimize weight without sacrifice of strength.

If you think of the primary purpose of the varnish to be UV protection of the epoxy, the higher the UV absorbing ability of the varnish, the thinner the varnish need be. This sounds trivial, but varnish can add several pounds.
Alan
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Bryan Hansel
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Post by Bryan Hansel »

Jim, that veneer canoe sounds like cold molding. At the Sawbill Outfitter's up the Sawbill Trail from Tofte, I believe that they have a cold molded canoe in their employee housing area. I've seen one recently and that seems like the most likely place that I would have seen it.

There was a website awhile ago were a guy was trying to sell Wee Lassies made with thin veneer cherry inside and covered with carbon fiber. The weight of the kayaks was super minimal.
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Dana
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Post by Dana »

Hi folks:

I just finished my first canoe, a 15-foot Bob’s Special built with an eye for light weight and it came in at 50 lbs. which feels very light to me. I did a few things to keep the weight down but not everything I could have. I think the biggest savings in weight are found in using cedar instead of hardwood whenever you can. I ended up with a strong hull, normal looking decks and the deep sculpted yoke I wanted and the canoe is still pretty light. I’m very happy with it.

Here is what I did and didn’t do to keep the weight down.

1/4 inch Eastern White cedar strips . . . said to absorb less epoxy?
3/4 inch cedar inner stems
1/4 inch ash outer stems . . . looks nice too
3/4 inch cedar inner gunnels with scuppers
5/8 inch cedar outer gunnels with 1/8 inch ash laminated to the outer edge
Outer gunnels tapered
All gunnels epoxied to hull, no screws
6 oz cloth inside and out
Used 4 light coats of Mas epoxy inside and out
Cherry seats mounted on hull blocks, 4 screws the only hardware
1 1/4 inch thick sculpted cedar yoke
Yoke morticed into gunnels and hull.....no hardware
16 inch cedar decks are 1 inch at thickest part
Decks epoxied to hull and 4 screws
No keel or stem band
Bare hull was 36 lb glassed

Dana
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