What type of ship did Leonardo da Vinci propose with two parallel hulls for greater stability?

Leonardo da Vinci proposed a double-hulled ship designed to improve stability on the water.

The concept used two parallel hulls connected by a deck or supporting structure. Separating the hulls widens the vessel’s base, reducing the tendency to roll compared with a single narrow hull.

This arrangement is known today as a catamaran configuration. Leonardo explored it within a much broader body of studies on boats, waterways, propulsion, and hydraulic engineering. His sketches addressed both practical transport and military possibilities.

Leonardo did not invent every principle associated with twin-hulled boats; multihull vessels have much older histories in several regions. His drawings are notable for applying careful mechanical observation to a European Renaissance design tradition.