: Anybody know if those screws driven into PVC pipe will hold?

I said early on that this was still in the "experimental" stage. They should hold just fine, but the only proof of that is to actually build a few boats like this and beat them to pieces just to see how much abuse they can take.

Nice thing about this is that you'll only need about $25 worth of PVC pipe, so breakage and experimentation are not going to be too expensive. Frames and floor should only use 1/2 sheet of plywood (about $10) and one sheet of lauan (again under $10) should do for all the reinforcing of the PVC tubes. Add on 6 yards of heavy vinyl at $3.50 a yard and the whole thing should come to well under $80.

While the illustration only shows 4 screws, that was just for simplicity in drawing. Each screw is going to hold with a certain amount of force. For a stronger bond of wood to the pvc, you just use more screws and space them closer together. That kind of redundancy also ensures that one or two loose screws won't compromise the integrity of the pieces.

It is also possible to use machine screws or bolts and secure them with nuts which are inside the tube. Holding the nut while you tighten the bolt is going to be a problem, but not an impossibility. A "T" nut inserted into a dowel rod (making a barrel nut) is one possible way to do it.

Or, you can put a wood plug in the tube, drill through it and insert a bolt. The head of the bolt can be recessed into the wall of the tube and the hole smoothed over with bondo, epoxy or even chewing gum. The threads of that bolt would then protrude into the interior of the kayak, as studs. You would put the plywood over those studs, and secure the pieces with nuts, washers and lockwashers on the inside of the boat.

The more complicated the process the more it will cost, and the more time it will take to make. At the point where it gets too involved, the advantages of using PVC are outweighed by the disadvantanges of the other steps.

PGJ