Sheer

By the dictionary:

"The longitudinal upward curvature of the deck, gunwale, and lines of a vessel, as when viewed from the side."

In strip built construction, the sheer strip is the first strip applied on the side of the hull. It divides the hull from the deck, if only for the purpose of building a deck and hull in two pieces that are later joined after removing the forms.

In plastic boats, there is often a mold mark at the sheer line, and this line is an important reference point for drilling holes for footpegs.