Bill
I had damage at the tail and a bad repair that went through to the inside. I recorded and rebuilt the aft part, from the last stringer back on the inside. I don't think this was necessary, but I did get rid of the vermiculite this way, all of the nasty stuff is gone. Also my floor was squishy, all of the balsa core was bad.
The rest of the recoring around the keel is proceeding from the outside. Relatively speaking, the inide structure is massive compared to the outer skin around the keel. The inner tabbing is about a half inch thick and extends about 18" to either side. Then there'd be stringers to rebuild. About enough inside that the core and outer skin aren't structurally necessary.
The outer skin around the keel has three layers of roving for about 6" out, two layers out to about 12", and one layer beyond that. Much easier to rebuild the outside than the inner structure, even fighting gravity.
I'll post some pics of dissected pieces in my blog.
