Leonardo da Vinci proposed a double hull to protect ships from damage and leaks.
The concept placed a second layer inside the outer hull, creating a space between the two skins. If the exterior were breached, the inner layer could help keep water out and preserve the vessel’s buoyancy.
Modern tankers and some other vessels use double hulls for safety, but Leonardo’s Renaissance proposal was not a direct blueprint for modern ship construction. His notebooks contain many ideas about naval engineering, including ship design, pumps, and defensive mechanisms.
A double hull is different from a double-deck ship. The term refers to two layers forming the bottom or sides of the vessel, not two passenger or cargo levels.