Leonardo da Vinci sketched a boat with a double hull, placing two hulls side by side as a stability and safety concept.
His notebooks include marine designs that explored ways to keep vessels afloat after damage. A double-hull arrangement creates separate buoyant compartments, so water entering one section does not necessarily sink the entire craft. The concept also resembles the basic two-hull layout later associated with catamarans.
Leonardo’s drawing was not a modern shipbuilding specification, and the historical record does not show that he built or tested this particular vessel. Its importance lies in recognizing compartmentalization and separated buoyancy as useful engineering ideas.
Double hulls later became especially important in ships carrying oil and other hazardous cargo. Modern tanker regulations use an outer hull to provide additional protection if the inner cargo tank is punctured. Leonardo’s Renaissance sketch therefore anticipates a principle that became central to later naval architecture, although the exact purposes and construction methods differ.