What type of boat did Leonardo da Vinci design with two hulls?

Leonardo da Vinci designed a catamaran, a boat with two parallel hulls.

His naval sketches include a twin-hulled vessel intended to improve stability on the water. Separating the hulls creates a wide platform of support, a principle used by catamarans today for sailing, transport, and racing. Leonardo’s interest in such designs reflected his broader study of water resistance, propulsion, and military engineering.

The drawing should be understood as a proposed design, not evidence that Leonardo invented every feature of the modern catamaran. Twin-hulled boats have appeared in several maritime traditions, including long-established vessels in the Pacific and Indian Ocean regions.

This design also differs from Leonardo’s paddle-wheel boat. The paddle-wheel concept concerns propulsion, whereas the catamaran concept concerns hull arrangement and stability.