When dealing with earlier built balsa core
boats, check if the core
was cutback so that the two glass skins come together as a solid mounting in the areas where hull
penetrations are present. Particularly thru-hulls. Check how that skeg is mounted, just glassed place, or thru bolted to plates in a solid area.
Look at the area around the mast
partners, and how the deck layup
was sealed before making the gunwale joint.
These were all points of special attention on the PVC core boats we built, and are areas where I have done common repairs
on balsa boats.