Two large ship propellers found near some wharf on the north side of San Francisco, California, USA, 2002-09. Note the erosions on the edge of the blades, caused by air bubbles when it spins fast (called Cavitation).
A propellers on exhibit in a northen wharf of San Francisco, California, USA, 2002-09.
This boat propeller measures approx 116cm in diameter. (photo from a email contributor, 2004-09)