Leonardo da Vinci designed a catamaran, a boat with two parallel hulls for greater stability.
A catamaran uses separate hulls joined by a deck or framework. Spreading the buoyant volume across two hulls gives the craft a wide base and can reduce rolling compared with a single-hulled boat. Leonardo’s design is often cited as an early example of thinking about this arrangement in a practical vessel.
The word catamaran comes from a Tamil term referring to a type of raft, so Leonardo did not invent the general idea of multihull boats. His significance lies in the surviving design evidence and his systematic approach to improving watercraft. He explored many maritime mechanisms, including propulsion and methods for reducing resistance.
A catamaran is not simply a wider barge. Its defining feature is two distinct hulls, usually with an open space between them. Modern catamarans are used for sailing, transport, racing, and passenger service.