Which Leonardo da Vinci design used a double hull to reduce damage from collisions?

Leonardo da Vinci designed a double-hulled ship intended to reduce the danger of damage from collisions.

The concept places one hull inside or alongside another, creating a protective space between the outer surface and the ship’s main interior. If the outer hull were breached, the inner structure could help keep the vessel afloat and protect cargo or passengers.

This principle resembles the safety logic of modern double-hull vessels, although Leonardo’s drawing should not be treated as a direct blueprint for a modern tanker or submarine. Renaissance shipbuilding used different materials, joining methods, and structural assumptions.

Leonardo was especially interested in naval engineering because ships were important for trade and warfare. His notebooks include studies of hulls, oars, rudders, pumps, and methods for making vessels more durable. The double hull is therefore one part of a broader program of practical watercraft design.