Leonardo da Vinci proposed a double hull as protection intended to reduce the danger of a ship sinking after damage.
His notebooks contain naval designs that include a second layer around a vessel’s main hull. The space between the hulls could provide additional protection if the outer skin were breached. The concept anticipates a principle used much later in shipbuilding, especially for improving resistance to collision damage and containing leaks.
Leonardo’s maritime studies covered hull forms, propulsion, dredging, and canal engineering. They were design investigations rather than evidence that he built a large fleet or standardized double-hulled ships. The drawings also do not amount to a modern naval safety specification, so later engineering practice should not be projected directly onto every detail.
Modern double-hull construction is especially associated with oil tankers, where the separated outer and inner structures help reduce pollution after a collision or grounding. Leonardo’s sketch is historically important because it shows an early recognition that layered hull construction could improve survivability.