On smaller boats like daysailers, the deck attaches to stringers (a
structural wood or fiberglas piece running along the hull edge)along
the hull and fastened with either screws or is glued.
For larger boats, weak hull-to-deck joints were the hallmark of poorly
built boats in the late 70s and early 80s. Some boats actually were
only glued at this joint. Slightly better ones were glued and riveted.
Best have inward turning flange on the hull with a downward turning
flange on the deck. There is 3m5200 between them and they are
thru-bolted (vertical bolts)every few inches through the toe-rail.
Hurricane damaged boats can reveal a lot about how this joint is done
as this is a common failure area due to extreme abrasion there. This
past year, I saw a boat that had banged against a piling so hard that
the aluminum rivets at the joint had broken and the hull and deck had
separated for 6'