Leonardo da Vinci proposed a double hull as an underwater feature intended to make ships safer against leaks.
A double hull places an additional layer of structure inside the outer hull, creating a protected space between the sea and the vessel’s interior. Leonardo’s naval studies included the idea of dividing or reinforcing a ship’s lower structure so that damage to the outside would not immediately flood the main compartments.
The concept is related to modern damage-resistant ship construction, but Leonardo did not invent the complete modern double-hull system used on every type of vessel. Today, double hulls are especially associated with oil tankers, where the extra layer helps reduce spills after a collision or grounding. Leonardo’s drawings show his broader interest in naval safety and practical mechanical engineering.