Water Screws

By Xah Lee. Date:
boat propeller boat propeller
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).
boat propeller boat propeller
A propellers on exhibit in a northen wharf of San Francisco, California, USA, 2002-09.
boat propeller boat propeller
This boat propeller measures approx 1.16 meter in diameter. (photo from a email contributor, 2004-09)
boat propeller
Propeller for a small boat. [ image source ] [ 2018-12-31 https://en.wikipedia.org/wiki/Image:Cavitation_Propeller_Damage.JPG ] The scars on the blade are cavitation damage.
Schraube Europa 04
MS Europa, build in 1938.
Schraube U Boot
Submarine from World War 1.

Above photos are taken in the Villa Hügel, Essen, Germany, ~2004, contributed by Volker Peters.

Propeller Prinz Eugen01
«The Prinz Eugen was build in 1938 at Germania-Werf Kiel, it was a heavy cruiser in World War 2. The ship sunk on 1946-12-22 after two tests of atomic weapons.» — photo taken by Volker Peters, 1999, Laboe (Kiel, Northern-Germany).
Propeller Prinz Eugen03