: It seems to me that the c-beam would be stronger and simpler than the method
: you describe here. So I'll go with c-beams this time.

Let me try to clarify. You DO build "C" beams, but you build them AFTER you position the PVC stringers, and not before. (From your later comments it sounds like you are doing it this way.) The stringers are held temporarily with cable ties (or duct tape) to the ribs, bow, and stern. After all the PVC parts are aligned you bolt on the plywood panels that make your sides into "C" beams. teh plywood of course goes on the inside of the boat so the skin never rubs against it. This way you can position the plywood so it is right next to the upright side of a rib. This not only helps to keep the ribs in their proper places, but the gap between the two adjacent plywood pieces serves as a track that you can slide the ribs into when you reassemble the boat. And, the plywood is next to the rib, so you can fasten the rib to the plywood, instead of drilling more holes in the PVC stringer.

After you build the entire boat frame you cut the sides to an nice length for storage and attach the connectors for reassembly. think about how big you wnat your stored boat to be. You can cut the sides into 3 or 4 parts. the more parts you have the smaller the stored package, but the more connectors (or hinges) you'll have to deal with when you reassemble the thing. Cut it in thirds and your pack would be about 6 feet long. Still small enough to go by plane, but it might be a bit large for a trunk on a compact car, although it should fit inside the passenger compartment. Storing in a closet would be no problem. Cut it in quarters and the package would be about 4 1/2 feet long, and should fit in a car trunk.

: For connecting the stringers: Are you not concerned that this would weaken
: the joint too much?

Weaken the joint? Nah. The combined area of coupler and pipe is easily the thickest, strongest and most rigid spot. Even with one side not being glued, the pipe can't come out unless you take off the skin.

If you use fittings made by Lasco, and send them a picture, they may send you a golf shirt. Check their website: www.lascofittings.com for information.

: Yes, I am - Putz has a stringer on each side of the keel.

Your PVC might be more flexible, though. Since you are building a folder, and you can take the skin off, if you feel you need more stringers on the bottom it should be rather easy to add them later.

: . . . it looks like it'll come in well under $100 (I'm at
: $45 right now).

The skin and the waterproofing material for it will be your costliest items I think. Since your frame is made of plastic you won't be spending any time or $$ on sanding and sealing it.

Keep up the good work.

PGJ