Thanks Lincoln;
I do have 5.5 lb/cu.ft.12mm Core Cell foam.
I'd like to glass between the two layers with 900g (24oz) biax glass and the outside as well two layers of biax.
Plus glass where the tabs would be touching foam ,both sides of tabs.
How does that sound?
Ply is stronger ,but not to be dumb ,...why would they break other than rot in them over the years ?
Jim