: Many thanks for a thoughtful and detailed reply. I've had to digest it over
: quite a number of readings. Some newbie questions continue (and thanks for
: your patience!)

Answers to some of these questions are slearer if you can see the pictures in Putz's book. Read up o how he assembles the Walrus design and basically substitute PVC pipe for some of the materials. You can do this in your head, or buy a few sections of PVC pipe and play with it.

: Assuming that I'd make my ribs out of heat-bent PVC, where would you suggest
: I go for a template for my ribs to produce a boat that did well on the
: water? (if I'm going to do the PVC thing, why not stay with just the one
: material?)

The Walrus, as seen in Putz's book, is built over forms cut from plywood. Once the outer shape is determined by the longerons being algned on the forms, Putz has the builder add the stiffening and strengthening braces. Until the braces and floorboards are added the boat will collapse if it is removed from the building forms. The forms determine the design shape, the bracing is there to make sure the boat keeps that shape when it is on the water.

: Would Putz' book give me rib templates? I've got Morris' book and am
: considering using some of his measurement rules. I'm interested in your
: site as well - can you share the link?

Putz's book gives the building forms. Many people use that info, though, and make pieces with the same measurements to be used as ribs. But, you cna insert bent PVC tubing almost anywhere you want to give you the shape and bracing your frame needs

: Good point. They also have a partial plywood floor. Should I consider that as
: well?

Go with 3/8th inch plywood if you go that route. 1/4 inch plywood seems to sag too much for me. Or, you can rip a 1x4 or 1x3 into two pieces and plane those to be 1/4 by 3 1/2 or 1/4 by 2 1/2 inches.

: So the ends of these angled braces would be permanently attached to the long
: pieces, and the "short tubing" could be dismantled?

No, the short tubing is permanently glued into place. This forms the bracing for the side panels (trusses) which wil run the ful length of your kayak, and be disassembled into shorter parts when necessary to pack the thing.

: I seem to recall reading that too much PVC glue actually weakens the
: material, so I think I'd want to limit my use of it. What do you think
: about making a jig that supported the PVC pipe, then using a drill of the
: proper diameter to essentially "cut" through the pipe. This
: would give me a rounded end that would mate very nicely with it's intended
: long piece. Thoughts?

All the plastic plumbing fittings on PVC pipe in my house are solvent welded on. If the solvent weakens the plastic then it does so only slightly. Obviously the glued joints are strong enough to hold up to water pressure for years. the fittings are made of heavy material. I don't think a pipe to pipe connection is a good, strong bond. You need to add the coupling or other appropriate fitting for reinforcement.

: I agree they'd need to be the same length. But I'd want to be able to
: dismantle it all somehow. Are you thinking that I'd build this
: "truss" (hope I got the term right), and then have joints in it?

Yes. Instead of having a bag with only round tubes, you would have some round tubes and some panels made from tubing. The panels would look like small "I" beams. if they don't go full length then you need to join them to other pieces.

: In other words, say 4 "mini-trusses" that join to create the
: full length one? (And, sure, it would undoubtedly make more sense to build
: a boat that can't be dismantled first - as a learning exercise. But if I
: was sensible, would I really be doing half the things I do anyways?)

: I think that severing it by drilling through would take care of this, no?

The drilled piece would give a small bonding surface, so the glue joint would be weak. All the braces are instaled with solvent and permanently glued into place. Actually, considering how the solvent works, the better term is "solvent welded" into place. You can cut the trussed sided panels into 3 or 4 or more parts for carrying, and either hinge them or re-connect them iwth PVC connectors. (glue one side and allow the other to be a tight friction fit (no glue).

: This may be the simpler method by far. Anyone have an idea where I could find
: PVC sheet stock?

Check your local for addresses and ask around at the local hobby shop for it. What town/state are you in. Someone may be familiar with your neighborhood.

: Need I be concerned about weakening of the PVC from heating?

NO, the strength comes back when it is allowed to cool.

:What do you
: think the best method of heating and working with the pipe would be?

I was very impresed with an article in Boys Life magazine about a troop that built snowshoes from PVC pipe, which they softened and bent into shape using heated sand that was poured into the tubes. There was a good picture of the forms the used for holding the pipe in shape while it cooled. The sand kept the walls of the pipe from collapsing while the pipe was being worked with, and it transferred a lot of heat. Optometrists use the same principle to heat the ends of eyeglass frames so they can be bent to fit the head of the eyeglass wearer.

: I wonder if I could make my first large rib using a form cut out of that
: really thick cardboard used for packing appliances (the 3" stuff).
: Then use rib one as the exterior form for rib two, and so on - each
: concentric circle providing the form for creating the next. Might this
: work? Potential pitfalls?

If the cardboard is free, go for it, but I think it might be difficult to cut anything that thick. If you are sort of money and long on cardboard you cna laminate three or four layers of corrugated cardboard with white glue. Place alternate layers with the directions of the corrugations perpendicular to each other. Weight it and let it harden. Otherwise use inexpensive OSB (Oriented strand board) or plywood. Once the shape of the hull is determined, make ribs that meet the other hull components and brace them into the shape they are supposed to maintain when the frame is removed.

: Or could I go back and add cross members (not sure that'd be the right term)
: at an angle if it turned out that the boat was not rigid enough?

regarding the skin:

: And I'm guessing I'd have the lace secured up by the
: cockpit so I could adjust it and tighten it up while in the boat and on
: the water?

Sounds like a good plan. I like to keep the knots in things visible so I can see if they get loose.

: It helps a lot - I can't tell you how much I appreciate your noodling this
: one along with me. Perhaps someday I'll be of help to another newbie.

Please do. The only way any of us learn is through personal experimentation, or by having someone pass on the results of their experiments or theories.

(And
: I do have the bug in a big way. After making this take apart boat, I fully
: intend to build a more respectable S&G vessel - the photos I've seen on
: this board are too compelling not to!)

No, what you should do is make PVC boats that look equyally compelling but assemble in less time, cost less, handle as well or better, and don't need to be sanded. Then all the S&G people will want to build things your way. Strip builders are incorrigible, though. They'll keep building with strips.

: Again, many thanks,

You are welcome.

PGJ