I dropped by Warren Williamson's workshop the other day and he showed me the progress he has made on his custom stitch and glue Greenland kayak. The panels have been joined together -- spot welded with thickened epoxy, but no fillets or fiberglass yet. The panels came together easily to form a beautiful, sleek and lightweight symmetric hull.
Some building notes:
Since the hull panels were cut with a CNC router from 8x4 sections of plywood, they had to be joined together using butt joints and "butt blocks". Using a butt joint is much easier than trying to scarf together thin plywood panels. Warren was a little concerned about getting the joint right, because a small error in lining the panels up at the joint will be magnified at the ends. So he basically lofted the panel out full scale and laid the panels out on the diagram before joining them together. If you look very carefully along the length of the hull you can see flat spots where the joints are. Warren said that using smaller butt blocks might have avoided this. One could also try using a few sheets of fiberglass instead, which apparently what Pygmy does.
For stitching the hull together, he used two external forms, internal building forms and four permanent bulkheads. There is a small bulkhead at both the bow and the stern, which help give the hull a concave shape at the ends. This will produce a small air chamber at the bow and stern which will need to be vented.
The deck in the forward cockpit area is stitched together from five panels. Using several panels instead of a single panel bent ("tortured") over frames (the method Chesapeake Light Craft uses) keeps the deck from being under constant tension. It also simplifies sealing the underside of the deck, since the underside of the deck can be fiberglassed prior to installation. In CLC kayaks, the underside of the deck is coated with epoxy only (no fiberglass) and installed while the epoxy is still wet.
Warren installed a "sheer clamp" around the inside of the sheer. It looks like it's about a half-inch by half-inch length of cedar, tapered towards the ends. A rolling bevel along the top surface of the sheer clamp facilitates joining the hull and the deck. The sheer clamp helps keeps the hull fair, since the plywood is very flexible without any support. In CLC kayaks, the deck is nailed to the sheer clamp. Nails are necessary because the deck is bent around a form and under tension. Since his deck isn't under tension, Warren says he can simply join the deck with a bead of thickened epoxy and avoid the appearance of ugly exposed nail heads.
By the way, Warren is building this kayak in what is basically a large tent that he built in his backyard. If you talk to enough boat builders you can't help but be impressed with what people will go through to acquire workspace to build their boats. For instance, another friend of mine built his Pygmy Arctic Tern over a winter in a rented 10 x 20 ft unheated mini-storage unit, equipped with a single exposed lightbulb and one electrical outlet.