Leonardo da Vinci sketched a double-hull ship design as a way to improve buoyancy and reduce the danger of sinking.
A double hull places an inner hull inside or alongside an outer hull, creating a space between them. In Leonardo’s naval studies, the arrangement was connected with the idea that damage to one side would not necessarily flood the entire vessel.
The concept belongs to his broad investigations of ships, canals, water flow, and military engineering. It should not be confused with a catamaran, which has two separate hulls joined by a deck and is a different vessel arrangement.
Modern tankers use double hulls primarily to reduce pollution after collisions or groundings. Leonardo’s sketch was not a modern tanker design, but it shows an early interest in separating a vessel’s buoyant interior from an outer protective structure.