Leonardo da Vinci proposed a double hull as a ship-hull improvement to reduce damage from leaks.
Leonardo’s notebooks contain marine designs that include the idea of separating the outer hull from an inner hull. The space between them could provide added protection if the outer skin were damaged, helping keep water away from the vessel’s main interior. This is an example of his broader interest in shipbuilding, hydraulic engineering, and structural safety.
A double hull is not the same as simply making a ship’s planks thicker. It creates two layers with a protected space between them. Modern tankers use double hulls primarily to reduce oil spills after collisions or groundings, and many other vessels use related compartmentation. Leonardo’s proposal predates those modern regulations by centuries, but the historical drawing should not be treated as a complete modern naval design.