Hi Andrew, I would construct special station molds at each point where you want the boat to come apart: I would double-up the molds at those two points. Then, once the boat is stripped, you could fillet those molds in place as your bulkheads and cut along the dotted line. You could enhance those particular molds by fairing the edges, making them from cedar, etc. If you did it this way it would be prudent to insert 1/4" spacers where you intend to make your cuts (between the doubled-up molds); then you are still in the business of removing wood... not trying to add wood back later

It's a really cool idea. I'd be interested to see such a project underway.