Leonardo da Vinci proposed a double hull to improve a ship’s buoyancy and safety.
Leonardo’s notebooks include ideas for ships with two layers of hull separated by a space. The concept could provide extra protection if the outer skin were damaged, because the inner hull might remain watertight. It also reflects Leonardo’s interest in designing vessels that were more resistant to flooding.
A double hull does not make a ship unsinkable. Damage, poor construction, or flooding above the protected region can still threaten stability. Modern ships use double-hull arrangements for particular safety and environmental reasons, but their engineering is far more complex than Leonardo’s sketches.
Leonardo explored many maritime ideas, including canal machinery, diving equipment, and vessels powered or moved by mechanical systems. His double-hull proposal is best understood as an early conceptual approach to compartmentalization and protection against hull damage.