Via the Independence Seaport Museum: Cruiser OLYMPIA’s two propellers (screws) were 14 feet in diameter and had three blades. The screws, like on most ships, counter-rotated from each other to prevent the ship from straying off course. They were also bent twice in her career!
The Cruiser Olympia Association long ago used one of the screws, which were removed when Olympia passed into use as a museum ship in 1957, for a series of commemorative coins that helped to fund the group’s operations. The 32mm bronze coins were issued for the 60th anniversary of the battle in 1958, although the Museum still had a number left in their gift shop when I visited in 2013.
From my collection: