A hard chine is a design feature where a boat’s hull sides and bottom meet at a sharp, distinct angle rather than a smooth, rounded curve. Common in modern, high-performance, and plywood boats, this design provides increased stability, greater internal volume, and improved planing performance compared to rounded hulls.

Key Characteristics and Benefits
Performance: Hard chines improve planing capability, allowing boats to lift and glide faster, which is ideal for racing.

Stability: They provide increased "form stability," making the vessel steadier at rest and when heeled over.

Construction: Hard chine hulls are often easier to build with flat materials like plywood or metal, as they do not require complex, compound curves.

Handling: The sharp edge can enhance tracking and offer better "bite" into the water while turning.