Leonardo da Vinci sketched a double hull as a ship-safety feature using two layers of a vessel’s hull.
His maritime studies included ideas for improving a ship’s resistance to damage and flooding. A double hull places an inner hull inside an outer hull, creating a protective space between them. Leonardo’s notebooks contain related ship designs and structural studies, although they do not represent a modern naval standard in every detail.
The concept is important because separating the cargo or passenger space from the outer skin can reduce the chance that a collision will immediately breach the main compartment. Modern double-hull construction is used in many ships, including oil tankers, where it helps protect cargo tanks during some groundings and collisions.
Leonardo’s sketch should not be treated as proof that he built a double-hulled ship. It is better understood as an early recorded design idea that resembles a feature later adopted in naval engineering.