Leonardo da Vinci proposed a double hull as a ship-safety feature.
His maritime studies included vessels with an outer shell and an inner hull, creating a space between the two layers. The arrangement was intended to improve a ship’s resistance to damage and water entering through the outer surface. Leonardo drew and described this idea during his investigations of naval engineering.
A double hull is not the same as simply making a ship’s planks thicker. It creates a separate protective layer, a principle later used in several kinds of ships and marine structures. Modern tankers commonly use double hulls to reduce pollution after collisions or groundings.
Leonardo’s drawing was a Renaissance proposal, not evidence that he built a modern tanker. Its importance lies in recognizing a protective structural principle centuries before widespread industrial use.