What double-hulled ship design did Leonardo da Vinci create to reduce the danger of sinking?

Leonardo da Vinci created a double-hull ship design intended to reduce the danger of sinking after damage. The concept placed an inner hull inside an outer hull, creating a protective space between them.

A double hull can provide redundancy: if the outer skin is breached, the inner hull may continue to keep water away from the vessel’s main interior. Leonardo’s design is commonly associated with his studies of naval engineering and military technology in the late 15th and early 16th centuries. His notebooks contain many proposals for improving ships and their handling.

Leonardo did not invent the modern tanker regulations that later made double hulls important in maritime safety. Contemporary double-hull tankers use carefully engineered compartments, structural members, and systems designed for oil transport. Leonardo’s sketch was an early conceptual treatment of the same broad protective principle.

The design should not be confused with a catamaran, which has two separate parallel hulls supporting one vessel. A double-hull ship has one vessel with an outer shell and an inner hull. Leonardo’s proposal is significant because it applies layered construction to the problem of marine damage control.