John,

You guessed correctly. Two issues. Stich and glue does not have the accuracy to build the three sections seperately and expect to have a fair boat. Also, Even if you built the boat on a strong back with temp bulkheads, it still would be very difficult to get the plywood to bend into a fair curve already cut into sections. The bow and stern sections would end up very triangular and the center section very tubular. Where they joined would be very ugly.

As you presumed, building as a single structure gets you fair curves. Once the curves are firmly "locked" (glued) in, one can safely cut the boat into sections and retain the designed curves.

Good luck and have fun with your build!

Joel

 Ditto what Joel said.  As nice as it would be (given a tight shop space) to build the Shearwater Sectional in three separate pieces, you'd never get a fair hull out of it, even with complex jigs or molds.  So the puzzle joints just fall where they may, and don't bear any relation to the take-apart joints in the Sectional.

Unless you know to look for it, you can't make out that the Shearwater Sectional comes apart:

As for Shearwater Sectional plans, that's just a permutation that we have not yet finished.  A good set of plans isn't auto-generated in the computer;  they are frightfully complex graphic-design projects undertaken by humans.  So we always have a backlog of boats that aren't available in the form of plans for scratch-builders.  We'll get to those eventually.