> Cavitation effects -- microscopic bursts of vacuum at low-pressure boundaries along the propeller -- come into play much sooner than with air propellers.

In liquids vapor-bubbles of the liquid (not vacuum) are caused by low pressure (or high temperature, boiling), and cavitation is the collapse of the vapor back to liquid state when pressure rises (or temperature drops).

Propellers in air do have issues with the speed of sound, but that's a different matter than cavitation in liquids.