What type of ship did Leonardo da Vinci sketch with two separate hulls?

Leonardo da Vinci sketched a double-hulled ship designed with two separate hulls.

A double hull can improve stability and provide a measure of protection against damage below the waterline. Leonardo’s maritime studies explored ways to make vessels safer and more effective, including arrangements that separated the ship’s main floating bodies.

The idea is associated with the broad range of naval designs in Leonardo’s notebooks. He examined boats, oars, mechanisms for propulsion, and methods for reducing the effects of collisions and leaks.

Leonardo did not create a modern catamaran in the engineering sense, and his drawings were not a complete construction plan for a vessel known to have been launched. The sketch is significant because it shows him considering separated hulls as a practical naval solution long before multihull ships became common.