Leonardo da Vinci proposed a double hull with two layers intended to reduce damage from impacts or breaches.
The concept placed an inner hull inside an outer hull, creating a protective space between them. Leonardo’s naval studies explored ways to make vessels safer and more resilient, especially in an era when ships faced collisions, shore damage, and military attack. The arrangement anticipated a principle later used in shipbuilding and marine safety.
A double hull does not mean simply adding a thicker single layer. Its defining feature is the separation between two hull surfaces. That space can provide structural protection and, depending on the vessel, help isolate cargo or fuel from the surrounding water.
Leonardo’s proposal was an early concept rather than a modern regulatory design. Contemporary double-hull tankers and other ships use advanced materials, compartments, and standards that were not available in Renaissance engineering.