The Khufu boat features no nails. Along with the puzzle-piece joggling, its builders connected adjacent planks with mortise-and-tenon joints, a kind of peg-in-hole technique. They also lashed the hull planks together with rope made from a grass called halfa. (Here, an original knot tied by pharaonic shipbuilders.) They didn't wrap the rope around or through the hull planks, which might have promoted leaks. Rather, they worked it through thousands of V-shaped channels they laboriously carved into the inside faces of planks. In essence, they sewed the ship together.