Leonardo da Vinci’s double-hull boat concept used two layers of hull to improve protection from flooding.
Leonardo explored double-hull construction in his studies of boats and naval engineering. The basic idea was to place an inner hull inside an outer hull, creating a protected space between them. If the outer shell were damaged, the inner structure could help keep water away from the vessel’s interior.
This principle resembles the compartmentalized protection used in later ships. Leonardo’s notebooks contain many studies of watercraft, including boats designed for transport, dredging, and military operations. His work combined observation of existing vessels with experiments in buoyancy, resistance, and mechanical power.
The double hull was not a modern shipbuilding standard in Leonardo’s era, and his proposals were not mass-produced. The concept is nevertheless important because it anticipates a familiar safety principle: separating a vulnerable outer skin from a watertight inner space.