I think I understand these drawings. The solid line are on the outside surface of the hull. Refer to the last picture you posted. The dashed lines are "hidden lines" and are on the inside surface of the hull.
Each drawing with a number (1, 2, 3, etc.) shows two timbers which are joined in a diagonal plane when viewed from the top down. These joints have complex curves, as do the timber themselves. Drawing #1 contains timbers 1 and 2 shown on the hull drawing. Drawing #2 contains timbers 3 and 4, drawing #3 has timber 4 and 5, etc.
You marked the edge lines with numbers 1 through 4. Lines 1, 2 and 3 lay on the outside of the hull, and line 4 lies on the inside surface of the hull. Line 3 is the joint between the timbers on the outside surface, and line 4 is the joint line on the inside surface.
The joints between the timbers themselves are not perpendicular to the outside and inside surfaces of the timbers, but angled. The joint between the two timbers is represented by TWO lines, which you numbered 3 and 4. The plane of the joint changes angle form top to bottom, which is why lines 3 and 4 cross each other.
Once you can understand the three dimensional curves, you can see you the timbers are represented on the drawing. The hard part is taking these drawings and making them into actual wooden parts.
