Scantlings include planking.
Since 99% of boats are made of something else than wood, scantlings
include not only the framing but the bottom and deck planking like
type of steel or aluminum plate and thickness. For composites, type of
reinforcements, fiber orientation, core, laminate stack, type of resin
etc. etc.
I would say that scantlings are the definition of the hull material
and structure.

Jacques Mertens
http://bateau.com