Solid - sort of...
Hello...My 76 is a solid layup on all hull skins - only core is on STB transom for OB wedge - also very poor but typical ply coring on underside of interior liner (berths and floor) - your MAIN decks should be end grain balsa - including the house but not sides of same - underside of cockpit coamings are ply again...Cheers...Sean Herron.