Which Leonardo da Vinci machine was designed to turn a screw using water power?

Leonardo da Vinci designed a hydraulic screw machine intended to use water power to turn a screw.

Leonardo's hydraulic studies included devices for lifting, moving, and controlling water. In one concept, flowing water would act on a wheel or paddle system, transmitting motion through gears to a screw. The screw could then raise water or perform related work. The design illustrates his interest in converting natural forces into mechanical power.

This machine should not be confused with Archimedes' screw, the ancient water-lifting device whose helical surface is rotated directly to move water upward. Leonardo studied and adapted many earlier mechanisms, but his hydraulic machine is a later geared power concept rather than the original invention of the ancient screw.

Because Leonardo's manuscripts contain studies, alternatives, and unfinished proposals, historians do not treat every sketch as a tested machine. His hydraulic designs are important chiefly for their systems thinking: water flow, wheels, shafts, and gears are arranged as parts of one energy-transfer mechanism.