Make a main roof frame. It’s essentially the same as a galley hatch, just bigger. We had a catastrophic failure first time skinning the roof panel. The frame was too light and the skin forces broke it. It had four ribs each a single thickness of ½ inch plywood.


Version 2.0 had 12 ribs, making six stringers each double thickness. Added a reinforcing layer of fiberglass tape with epoxy on top and bottom edges. More weight again…It worked this time. Had a bit of spring back. When I was a schoolboy I built balsa model airplanes that had wings that looked like that. I guess I never got over it.

And we finally get a panel.

On another thread I chatted with Mr. Lahey about how we ended up putting straight edges and clamps all over to get the ribs to align. If you look closely you see two longer oak straight edges clamped across the ribs, then clamped to the cross members to pull all the ribs up tight against the straight edges keeping things aligned. Also notice a full set of little triangular wooden gussets glued in at each corner.