Leonardo da Vinci proposed a double hull to help ships stay afloat after hull damage. His notebooks include ideas for dividing or separating a vessel’s outer structure so that water entering one part would not immediately flood the entire ship.
A double hull places a second layer of material inside or outside the main hull, creating a space between the two layers. That arrangement can provide additional protection against punctures and improve buoyancy after a breach. Leonardo’s maritime studies explored many related subjects, including hull shapes, pumps, locks, and methods of moving water.
The principle is not the same as a modern ship’s complete safety system. Leonardo did not develop a standardized naval construction method, and his notes contain proposals rather than a documented fleet of vessels built to those plans. Later shipbuilders independently used compartmentation and multiple hull layers for different purposes.
The double-hull idea is especially familiar today from oil tankers, where international rules require double hulls to reduce the chance of cargo spills after collisions or groundings.