Leonardo da Vinci sketched a double hull as a shipbuilding feature intended to help protect a vessel from flooding. The concept placed an inner hull within an outer hull, creating a protective space between them.
Leonardo was fascinated by naval engineering and studied hull shapes, water resistance, and methods for improving ships. A second layer could provide structural protection if the outer skin were damaged, though the effectiveness of any particular Renaissance design would depend on its construction and watertightness.
The idea should not be mistaken for the fully developed double-hull standards used on modern tankers and many other vessels. Contemporary ships use carefully engineered compartments, materials, and safety systems. Leonardo’s sketch is historically significant because it shows him considering a principle that later became important in maritime design, even though his drawing was not a modern shipbuilding blueprint.