The logistics around building the hemisphere was pretty easy. Each wedge was assembled on its own. Glue times and final weights were all very manageable.

The mid-ship is more challenging.

Mid-ship frame strength will come from assembling a contiguous frame element that goes all the way around the boat. So… I’ve decided to make each cross section from 3 layers of 1/2 marine plywood. This lets me stagger and sandwich lap joints. This is important because I will be eating 1/4 inch away from these members each place I rout for a lateral supports. Since the lateral supports will be in the same location left and right… I would be left with very little wood to keep things solid during glue-up.

Anyway… the first cross section is done and I am using now as the routing base for all the sets of vertical members. I lay the elements on top of this base, drill holes for the router jig and I am ready to go.

The router jig spins around a central pin and I can cut all of the radial rabbets in all the members of a single cross section. Now I have to cut 2 full sets to see if they mate properly, but they should.

Wish me luck.