Back in the 70's did they use balsa wood for a hull core? Cut the floor and stringers and transom out, the bottom of the hull feels wet. Dads thinks its cored...Anyone know?

Marine ply wood as far as I know.

Marine plywood in mine

Yep...I had marine plywood too...Its all gone now.

I believe mine was one of the only boats that had coring in the bottom.