Leonardo da Vinci proposed a double hull as a safety structure intended to reduce flooding after a ship’s outer hull was damaged.
His maritime studies included ideas for reinforcing vessels and dividing internal spaces. A second layer inside the outer shell could provide additional protection against water entering the ship. The concept reflects Leonardo’s broader habit of applying geometry, observation, and mechanical reasoning to practical engineering problems.
A double hull is not the same as a watertight compartment system, although modern ships may use both. In a double-hull arrangement, an inner hull is separated from the outer hull by a space. If the outer surface is breached, the inner barrier can remain intact and preserve buoyancy.
Modern double hulls became especially important in tanker safety. International rules adopted after major oil spills required many new oil tankers to use double-hull construction. Leonardo’s Renaissance proposal was not a modern regulated tanker design, but it anticipated a principle still used in naval architecture.