The next task was to design the Guppy cabin itself. A rib-and-skin scheme, infilled with rigid insulation and overlaid with thin sheet aluminum (0.24 ga, if I can manage it) seems like the lightest overall design. I started with 1/2″ marine ply sheets, to be cut into 1.5″ wide curved ribs. Below is my first cut-sheet pattern:
What I have tried to do is use as much of the sheet as possible. I then scaled up the original drawing to 1:1 scale;
printed it on multiple sheets of paper;
pieced them together on a sliding-glass door and taped them together;
laid the paper-mosaic onto the plywood sheet;
slipped carbon transfer paper under the mosaic; and
traced the design onto the plywood using a ballpoint pen.
The second cut-sheet leaves a lot of unused material between the irregular “chevron” shapes of the galley-hatch ribs. That wood will be cut up into blocking to go between the ribs.