Leonardo da Vinci sketched a double hull as a ship-safety feature.
His maritime studies included a vessel with an inner and outer hull separated by a space. The concept anticipated a basic principle later used in some modern ships: if the outer shell is breached, the inner hull can remain intact and help keep water out of the main compartments.
Leonardo’s ship studies belong to a broader body of work on canals, pumps, locks, boats, and hydraulic engineering. He was interested in reducing resistance, improving control, and protecting vessels from damage. The double-hull idea was a paper design rather than a documented Leonardo-built ship, so it is best understood as an early conceptual contribution to naval engineering.
Modern double hulls are associated especially with oil tankers and other vessels where collision or grounding can cause serious pollution. Their construction and regulatory requirements are much more complex than Leonardo’s sketch. The historical link is the shared protective principle of separating the cargo or internal space from the outer shell.