Leonardo da Vinci included a double hull in one of his ship designs to reduce the danger from leaks.
A double hull places an inner skin inside an outer hull, creating a space between them. If the outer shell is damaged, the inner barrier can help keep water from immediately reaching the ship's main interior. Leonardo's drawing shows that he was thinking about compartmentalization and protection below the waterline.
The concept belongs to his broad body of naval and hydraulic studies. He investigated hull forms, ship movement, locks, canals, and methods for controlling water. His work was drawn rather than presented as a complete, tested shipbuilding program.
Modern tankers and many other vessels use double-hull construction for safety, but their structures are far more complex. Leonardo's design should therefore be viewed as an early conceptual proposal, not as the direct blueprint for modern ships.