The first page of Leonardo's Codex Atlanticus shows a mysterious drawing. Analyzing its details, we discover that it is a circular mechanism with sixteen radial guns. The central mechanism looks like a boat moved by a double paddle. This secret weapon could be a circular warship that could rotate and fire in a 360 degree arc. The central gear wheels allowed for independent movement of the two mechanical paddles. If while firing the ship rotates, the crew can open, clean and reload the gun that is quickly ready to fire again. A round shield can protect the vessel, making it a warship with 18 bombards.