A chine is an angle on the hull of a boat. While many traditional boats used rounded hulls, modern boats often have at least one chine, and others may have multiple chines.
To identify where chines are on a vessel, look at where the bottom of the boat, or the hull, angles up toward the side, or topside of the hull. A vessel with a single chine resembles a V-shape at the bottom, because there is just one angled point. Some vessels have three chines, with one in the middle and one on each side. Multiple chines may be beneficial to large boats on rough waters for the added stability. Chines are generally referred to as "soft" or "hard," depending on how sharp the angles are. Hard chines have more defined angles than soft chines.