volvo penta 3 blade folding propeller dropping blades

[fordna]

my volvo folding propellers [2] both dropped their blades within hours of each other due the failure of the 3 hinge pin retaining set screws it was like a chain reaction 2 screws go = 3 pins gone with 3 blades then the other 1 screw goes= 2 blades; the anodes had gone on both. the remaining pin retaining screws showed no corrosion [i think] but the missing screw heads left the threaded part in the holes with looks like the heads were screwed off with some granular stress to the outside diameter has anybody suffered this ? my boat is a fontaine pojot lipari 41 built april 2011 sailed to australia\990hrs on engines

[Gordon]

Common fault if you let the anodes corrode away, have seen the same issue on a boat living in a marina with large amount of stray current in the water.