New project: 8ft folding canoe. Pvc stringers

[scotjack]

Really looking forward to seeing the end result.

[JohnSand]

I think you'll appreciate the extra length.

[davefman1984]

Ive more or less completed the frame at this point. some of you may be disappointed but I decided to go with an overall length of 11ft. originally it was going to be 13ft but the center section was far to flexible for my taste so I cut out 2ft from the center stringer sections. im pretty happy with the results. the open middle section is 4ft which is perfect for me. I've floated in boats with a smaller footprint so im not too worried about it keeping me up. the frame weighs a total of 21 lbs. ad the skin and it will be under 25 lbs for sure. I have some 1/4" thick baltic birch plywood I will probably use for an 6ft floor section. any thoughts or critique? im venturing into uncharted territory for myself so any tips or suggestions are appreciated.

[scotjack]

It to looks really good! If you want to do the "sea trial" in safe warm water, we have the perfect place in Montenegro.

[davefman1984]

Thanks for the offer but unfortunately I can only dream of such a trip right now. Maybe some day. My closest option is southern california and that may have to wait till next year. Either way I will post pics of my first water test.

[JohnSand]

I like it. I think the plywood is a good idea, I would attach it to every stringer, even if just with a lashing or zip tie. I think that will stiffen the structure, and spread out your weight.

[davefman1984]

I was going to have the seat platform resting on the ribs but if you think its better to have it resting directly on the stringers I will try to figure out how to make it work. Im planning on tensioning the skin by attaching short, thick rubber bands to the edge of the skin every foot or so with hooks on the other end that will attach to holes drilled on the underside of the second row of stringers from the top. I figure rubber bands are cheap and easily replaceable. I can carry several spares with the clips for the frame.

[davefman1984]

Ive got the locking clips installed in the frame and the skin attached for fitting. i found some spring tether clips for paracord at my local hardware store for .79 each. I'm going to install grommets in the top edge of the skin and have a 8 paracord tethers spaced evenly that wrap around the second stringer which can be tightened to snug up the skin. I like it much better than my previous plan for rubber band clips. i'm getting close to finished. maybe another week and it will be ready for testing. its definitely more like a canoe than a kayak in its design but im not aware of a folding canoe forum so you folks get to see this crazy experiment.

[JohnSand]

I think attaching your plywood sole to the frames will be good too. Keep us posted.

[davefman1984]

I have access to sheets of closed cell foam at work. I think im going to cut out 2 sections to fit under the plywood floor. I might attach the floor with parachord tethers

[voyageur]

what is the skin material you are using?
will you be able to get out all the wrinkles that way?
you must have to make a cut at the bow to remove overlapping material, how do you waterproof at seams?

[davefman1984]

I'm using dupont tyvek housewrap for the skin. tyvek is a membrane similar in performance to gortex. other house wraps on the market are micro perforated with tiny needles to allow water vapor to pass through. they all leak like a sieve while tyvek doesn't let a drop through. its slightly thicker than a sheet of paper and very tough. not the best performance for puncture resistance but I understand that going in.

I should be able to get most of the wrinkles out. the material does not stretch.

tyvek is very thin and acts like paper in the sense that it can be folded and creased. I glued the ends together to meet up at the frame and folded over to one side and glued down again with some tyvek tape to give added waterproofing and a cleaner look. I dont really have any seems below the water line.

this is completely an experiment for me so im not sure how it will perform. based on my research of the material it should work well but i wont know until its in the water. the frame is definitely good so I can re-skin with a better material down the road if need be.

[davefman1984]

The boat is finished and ready for testing. I hope to do that this weekend. Im pretty happy with the fit of the skin and the floor. The boat feels surprisingly rigid and if the skin doesnt leak I will call it a success. I have a couple of observations from the build that I might change in the future.assembly time is around 45 minutes due to the tedium of installing the 45 locking clips that hold it together. Im already working on a new method that will reduce the clip count to 10 for the same boat.

Im also redesigning to utilize hdpe plastic for the ribs instead of plywood because its stronger and less prone to breaking from being bent in the wrong spot.

Does anyone have a cheap source for 1/2" hdpe plate?

[JohnSand]

I don't know a cheap source of HDPE, or other sheet plastic.
That plywood will be stronger if you fill in the inside corners.

[davefman1984]

Do you mean round the inside corners to widen the material right at the corners?