Leonardo da Vinci proposed a double hull as a structural feature to reduce flooding damage in a ship.
A double hull places a second layer of structure inside the outer hull, creating a space between the two surfaces. If the outside is punctured, the inner layer can help keep water from immediately reaching the ship’s compartments. Leonardo’s notebooks contain ship designs and ideas for improving maritime safety, including arrangements associated with layered hull protection.
The concept shows Leonardo applying mechanical reasoning to naval engineering. He examined buoyancy, water flow, pumps, and methods for moving or protecting vessels. His work was not a complete modern naval standard, and the surviving drawings do not represent a single mass-produced ship design.
Double hulls later became important in shipbuilding, especially for tankers and passenger vessels. International rules eventually required double hulls for many oil tankers after environmental disasters highlighted the danger of single-hull punctures. Leonardo did not invent every later form of double-hull construction, but his proposed arrangement is an early documented example of the principle.