Skip Snaith discusses this method in his book, "Canoes and Kayaks for Backyard Builders". I don't own it but have read it. Check your local library for his book. If you like it, be sure to buy it, amazon.com has it used for $13.95.

Mike

: Today I've seen an unusual boat: a pinnace's tender. They're usually made of
: steel and hang from a cat-head or crane over the steerage. This one's made
: of ply and the joints were filletted with black tar. The plywood panels
: looked a bit blackened by tar, too.
: Worse, the rudder wasn't deeper than the keelson which was very deep indeed.
: I wonder if that dinghy was purely decorative or could those matt ply panels
: stand sun exposure with no epoxy or varnish?
: Fishing dinghies were painted but the chine joints were filled with tar. So
: were sewn boats.
: Is that a waterproofing alternative ? Did one of you ever use it?