The screw propeller was an invention race

Did an Italian inventor develop the screw propeller before the other claimants?

The answer rejects a clear Italian lead and describes a close race among four designers, followed by others developing altered propeller designs.

Claims to the practical screw propeller belong to a close invention race. The earlier reading names four designers working between 1833 and 1838 and places Francis Pettit Smith's British patent only six weeks before John Ericsson's. The later question raises an Italian priority claim, which is rejected in favor of that near-simultaneous development. Subsequent inventors contributed modified blade and angle arrangements, so first invention and later improvement remain separate questions.