Ultralight Aluminum "Skin on Frame" canoe

[shikeswithcanoe]

Hi all. I've been thinking about that post/thread where the guy made the 17 pound pirouge. He used aluminum trim coil/flashing for the sides. Had to go to Lowe's the other day so I thought I'd swing by and look at the stuff. A 14 inch wide by 50 foot long roll was pretty light (6.5 pounds I think). And playing with it I could see that it would be pretty darn tough even at that thin. It also came in coil widths up to 20 inches.

I have a 12 foot Bell "bucktail" canoe. I'd say it can handle a 200 pound load decently. If I did the calculations right it has about 30 square feet of surface area. The aluminum coil weighs about .11 pounds per square foot.

So, if I riveted up some metal, I'd have a skin that would be about 3.5 pounds. If I had the gunwales come down towards the water line in the fore and aft directions, which would be either something like a cross between a canoe and kayak or a canoe that is only used in areas without waves, I could probably get the skin down to 2.5 to 3 pounds.

Unlike its cousin, the Aluminum Grumman Battleship, this skin would be way to floopy to provide much rigidity on its own. So, you'd need some decent gunwales, frames, stringers, and thrwarts to provide rigidity.

I also weighed my 6 frames for my skin on frame kayak kit. They come in at 3 pounds too. And for this canoe you could probably shave a little weight off that as well.

So guys, think we could squeak in under the magical 10 pound mark? 15? Im pretty sure 20 would be easy, even for a slightly larger boat.

 

[Kayak Jack]

I'd like to see the build on that - and, if we were neighbors, I'd enjoy working right along with you on it. I strongly agree that an internal frame would be required; the skin by itself would not make a good monocoque structure, too flimsy. I'd think (hope?) that it wouldn't need as strong a frame as if you were covering with fabric?
Fastening would present me problems; I have no experience in tin bending (sheet metal work). An automotive body man would be right at home, I'd think. Another problem is imagining what shape in a flat sheet will curve and become the properly shaped panel when installed on that frame. Matt is the guy for that job. It's probably a lot easier to simply drape a large chunk of fabric over the frame, and then cut off anything that doesn't look like a boat. (Similar to carving a statue - start out with a large chunk of rock and simply chisel away anything that doesn't look like Venus de Milo. :wink: )

 

[woodman]

It would be easy to make cardboard templates off the assembled framework and overlap seams put it together with long rivets right into the stringers.

 

[Kayak Jack]

Well now, there you go - POUF!!! - a tin bender appeared.

 

[woodman]

Here is an example, the wings of my unfinished wind turbine. This is aluminum coil around a wood frame the rivets work fine even into the edge of plywood.. Don't mind the dust and cobwebs.

 

[Kayak Jack]

Neat - will that be a viable pitch turbine when it's done?

 

[john the pom]

I think Jack meant will that be a variable pitch turbine. Which would make it more viable. Due to its variability. Not to be confused with versatility. That completes my verbosity.
Brought to you by the letters "don't be a smart arse John." :mrgreen:

 

[woodman]

Here is where I got the palns, parts, magnets, a few yrs. ago
http://www.windstuffnow.com/main/lenz2_turbine.htm

 

[loafer]

man that was a quick steal
but back to the thread
don't forget that guy's skin was prestressed
that is' the panels were built flat then bent or pulled into shape
you can't just tack the ally to a frame
best of luck and keep us posted

 

[Kayak Jack]

The diagrams answered my question; they are fixed pitch.
Back to the boat - I think your idea of skinning a frame sounds better than the original he pictured.