Prop pitting
 

What does it mean when you have pits on your prop blades?

Pretty sure it is a result of cavitation. I seem to remember that microscopic low pressure bubbles form on the trailing edge of the prop eroding the metal. Hopefully some prop pros chime in here.

Indy is correct!!

Or electrolysis. You dock at a marina with big boats around lately?

Heavy cavitation. The little air bubbles around the prop "explode" and thats what causes the damage.