Delete comment from: Dark Roasted Blend
The propellers are NOT completely smooth despite appearing so. The ridge-effect you see is the result of polishing in a particular fashion that increases efficiency and decreases damage caused by turning through the water.
It's possible for water to damage the blades, and infact boil as the propeller spins through the water.
Apr 4, 2019, 2:34:39 AM
Posted to The World's Largest Ship Propellers