Older propellers were either phosphor, or manganese bronze. When new they were a shiny metallic reddish gold. They soon oxidised, and became a reddish brown, except at the blade edges, where striking waterborne objects, and cavitation would give a lighter colour. Of course modern propeller are totally different - separate blades, for controllable pitch propellers & Azipods are usually of exotic alloy steels. All the ships I served on had a spare propeller on deck, weathered to quite a dark colour.
A shiny propeller meant a ship fresh from drydock - or one that has run onto a sandbank! ( Yes we did that once ). One ship I was on managed to go astern over a mooring drum ( 2m dia x 4 long ). Chopped the drum up & took a chunk out of one blade. When at sea, you could hear the turbulence caused by the damage - a curious whistling warbling sound ( by the stern gland - where the propshaft goes through ). At the next port, we had divers grind off all the ragged edges
Dave
