A chine is the intersection point or angle where the side of a boat’s hull meets the bottom, running lengthwise parallel to the keel. It acts as a structural turning point that significantly affects stability, efficiency, and handling. Chines are categorized into hard (sharp angle) or soft (rounded) designs.

Key Aspects of Boat Chines
Hard Chine: A sharp, distinct angle between the hull sides and bottom, enhancing stability and, in some designs, providing lift and increased speed. Common in plywood, aluminum, and modern racing sailboats.

Soft Chine: A gentle, rounded transition between the side and bottom, often used to create a smoother, more comfortable ride in waves.

Reverse Chine: A type of chine that angles downwards, increasing pressure on the water to provide superior buoyancy, stability, and control in turns.

Functions: Chines provide structural strength, improve stability at rest, and can help direct water away from the hull to reduce drag (spray deflection).