Brett,

I think the idea of using carbon fiber or fiberglass tent poles for this boat is very good. The forms shapes, and manner of construction which George Putz suggests seems to be a very adaptable concept. If you don't have his book yet, get it and read it first, of course.

You could use frames cut from the original plans, or from my "translation" of them as bulkheads to support the carbon or glass pole -- but you might not need them. Like thwarts in a canoe, the supports for the deck and the floorboards provide the necessary cross bracing. If you need or want more, you can add short pieces of tubing as straight braces.

Pay particular attention to Putz's use of trestling for giving rigidity and strength to th sides. I suyapect your poles will be a bit more flexible than the wood strips, making the trestling mandatory. You can certainly put in those small trestle-like braces at the spacing shown by Putz, or for greater strength and stiffness you can place them closer together.

Here is an idea for mounting those braces:

Assemble the long tubes on the frame as per the instructions for using wood strips. cut your first (trestle) brace from a piece of tube and use a drop of hot melt glue to hole each end in place. Putz places his braces on the inside of the stringers. With the tubes you should place the braces inline and flush with the stringers. After you have a dozen braces held in with the tiny amounts of hot melt glue, secure them in place forever by wrapping the joints with narrow strips (about 1 inch wide) of bias-cut fiberglass cloth which has been pre soaked in epoxy resin. A piece 5 to 8 inches long should wrap around the stringer and the trestle ( brace) a couple of times.

Wind these joints tightly with nylon or polyester string, or monofilament fishline so they don't unwrap before the resin cures. If you use the fishline it should be unnoticeable after the resin cures, the others may be visible, but they won't rot like a natural fiber string, so you can leave it on.

If you get two or three layers of glass on all sides of the tubes in these joints you should have a joint that will flex a bit, but the braces will stay in place. With inch wide cloth strips your effective joint area will be bonding an area an inch on either side of the brace, and that should be plenty strong. By cutting these on a bias you can get the glass fabric to pack itself into the corners of the joints just by gently pulling a bit as you wrap the glass fabric.

You may want to lightly sand the entire length of the stringers before you intsll them. Then you won't have to sand in the areas of the joints with the braces.

You'll probably mix batches of 1 to 3 ounces of resin for each time you go to wrap the joints. Pour it on a sheet of aluminum foil and just dip your glass fabric in it to saturate the fabric, then squeeze out most of ther resin before applying. If your glass has too much resin in it then it will drip a lot.

When the resin is dry you can lightly sand each joint and put on a second coat of epoxy resin to help fill the weave of the fabric and remove any rough or sharp edges. A thin strip of sandpaper will do a quick job.

Floorboards can be installed in a similar fashion. After they are cut from plywood or solid boards, coat them with two coats of epoxy resin to waterproof them. Tack them in place with a couple drops of hot glue and then apply epoxy saturated glass cloth, wrapped around the tube and ending flat on the edge of the floorboard. Think of how you would hold these on with duct tape, and just use the saturated glass tape in the same manner. If the glass wants to come off, cover it with a small piece of cardboard covered with Saran wrap, and drive a staple through the works. When the resin has set you cna put the staple and the cardboard and plastic wrap will come away. leaving a tightly bonded piece of glass cloth.

Once your floor is installed on the floorboards the whole thing will be one solid unit held in dozens of places.

As for aluminum tubes: the big problem here is fastening the bracing to them. You might be able to weld them, but epoxy is not a long term adhesive for aluminum -- and I can't think of anything else that would be better.

For far less expense than carbon fiber, fiberglass or aluminum tubes why not use 3/4 or 1 inch rigid PVC plastic plumbing pipe? You can attach the bracing with solvent-welded joints that get strong in minutes and have a final cure in a day. You can use common joints for getting the necessary length. 45 degree elbows can be used for attaching the trestle bracing. I'd make a jig from a block of 2x4 to hold one of these elbows, and run the thing through my table saw so I could cut open the elbow. Then I'd be able to use these to attach the trestling at perfect 45 degree angles.

If you placed the joints for the stringers carefully, and only glued the connector to one tube, you could build a boat that could be taken apart for storage. The skin would be sewn around the boat in the stern, but in the bow it would simply be laced, like a shoe, to hold it on. Tighten the laces to tighten the skin.

Hope this helps.

Have fun with your project.

PGJ