Leonardo da Vinci proposed a double hull as a protective ship feature.
In his notebooks, Leonardo explored shipbuilding ideas that included placing one hull inside another. The outer and inner layers would create a protective barrier against damage, especially from impacts or breaches. This concept is recognizable as an early form of double-hull construction.
Modern double-hull ships use two separated layers of the ship’s bottom and sides in important areas. Tankers adopted double hulls widely because the arrangement can reduce the chance that a collision or grounding will release cargo directly into the sea. The modern design has detailed structural and regulatory requirements that Leonardo’s sketch did not address.
Leonardo did not invent the complete modern ship-safety system. His proposal is better understood as an early conceptual contribution to layered hull protection. It also shows how his engineering notebooks connected practical maritime problems with geometric and mechanical solutions.