Leonardo da Vinci designed a double hull as protection against damage to a ship’s outer skin.
His notebooks include concepts for reinforcing vessels with two layers of hull material. The space or structure between the layers could help keep water from entering the main interior if the outer shell were pierced. This is an early example of thinking about layered ship protection.
Leonardo’s naval ideas were connected to military engineering, especially the defense of ports and ships. The double-hull concept was not a modern steel tanker design and was not documented as a completed vessel built by Leonardo.
Modern double-hull ships use separate watertight layers and carefully engineered compartments. Their purposes include reducing pollution after collisions and protecting cargo tanks, while Leonardo’s proposal focused mainly on defensive survivability.