Chine

The sharp angle or edge formed where the hull’s sides meet its bottom, commonly found in hard-chined boats. 

A chine is a critical structural and design feature of a boat’s hull, particularly evident in vessels with a hard chine. It refers to the intersection or edge where the hull’s bottom transitions to its sides, creating a distinct angular shape. This feature contrasts with a rounded or soft chine, where the transition is more gradual and curved. The chine’s design significantly influences the boat’s performance, stability, and handling characteristics. For example, hard chines are often associated with planing hulls, as they provide a flat surface that helps the boat rise and glide on the water at higher speeds. This design is common in powerboats, racing yachts, and certain dinghies. Conversely, soft chines are more typical in displacement hulls, such as traditional sailing yachts or trawlers, where smooth water flow and efficient movement at lower speeds are prioritised. The chine also affects a vessel’s stability at rest and when underway. Hard chines can provide additional form stability, as the angular shape resists rolling, making the boat feel steadier. However, they may result in a rougher ride in choppy conditions due to their tendency to “slap” against waves. The chine’s placement, angle, and shape are carefully considered during the design process to balance speed, comfort, and manoeuvrability, depending on the intended use of the vessel.