Rehd,

Search for those pictures of Mike Hanks plywood version of the Walrus. I think he built it for under $150, and in record time.

First get George Putz's book if you don't have it already.

The construction is wood and chine. On a fabric covered boat the fabric is stretched over the chines, which are held in place by the ribs. With a stitch and glue there are no ribs, but the panels must be cut with great accuracy and assembled with care. With wood panels over chines you have an excellent compromise on building speed and cost, but you will sacrifice a bit in weight. Do you really care is the boat weighs 42 pounds instead of 36?

There are only five or 6 basic building frames, and these are all made of straight cuts, so you can cut them quickly with a circular saw. You can lay out these parts right on your plywood (or particle board) with a straightedge and a pencil. No fancy drawings or tissue patterns.

After the frames are cut the chines are attached to them with brads. You rip some plywood panels to a rough size and use a few clamps to hold them tempoarily to the chines. Trace the overhang with a pencil, remove them and trim with a bandsaw. Remount them -- this time with screws and glue. Or mount your oversize panels with screws and use a router with a laminate trimming setup to cut the panels to fit the chines exactly. then add a few more screws to keep things in place until the glue hardens. You can use epoxy if you wish. If you want to get a bit fancy, use a cloth gasket at each seam. Paint the chine, while the paint is wet lay on a strip of canvas, then paint that. while the whole thing is still wet, apply the plywood panel. as you tighten the screws you'll squeeze out a bit of the paint, and tighten the panel against the chine, pinching the "gasket" tightly. it is a cheap and fast way to seal out water at seams in wooden boats. For a high tech update of this technique, substitute glass cloth and epoxy resin for the cotton fabric and paint.

use 1/4 inch lauan for the hull bottom. if you can get thinner stuff you can use it for the sides and deck if you wish, or, to keep the costs down, use 1/4 inch lauan for the whole thing. It will be a few pounds heavier, but cheaper.

If you want to cover the exterior seams with fiberglass tape, or cut off glass cloth scraps, and some ply or epoxy resin, go right ahead. Otherwise, fill any cracks with a decent paintable caulking compound and paint the hull with a nice, colorful polyurethane or spend your excess pennies on boat paint.

Sanding is minimal -- the plywood panels are flat. Glas cloth on the exerior is not necessary. neither glass on the inside.

Putz goes into details on putting in floorboards, and trestling to support the chines. Since he is working with a cloth skin, he needs such things. When you use solid plywood over his frame you are replacing the open bridgework with a solid part. Klepper does this on their very fine folding boats, so the idea has been used for decades. the solid plywood bottom provides a solid base for a seat, or you can just glue in a few wedges shaped strips, to support a flat piece of 3/8 or 1/2 inch plywood in the cockpit area, and plop your seat cushion on that.

Cockpit and coaming construction is the same as on a stitch an glue. Maybe someone can give you some tips of doing a quick and cheap method for this.

forget the foam. It is expensive. For bulkheads, you just cut off the tops of your building forms and glue them into place. They should fit perfectly, but some shims glued around them will do the trick. Or, buy some float bags )(best option) or just get some mesh bags filled with soda bottles (cheapest option) and stuff them fore and aft to displace as much water as you can.

Hope this helps.

Paul G. Jacobson