I previously asked you if there was a weep hole at the bottom of the rudder because I suspected more than one modification in that area. It appears to me that I can see where the holes were for the zincs on the rudder.
If the previous owner removed and filled in the zinc mounts, the following questions should be resolved:
- Did you check to see if the weep hole still exists?
- Did you find where the bundle of yellow/green bonding wires join in the engine room near the top of the gray water sump?
- Have you done a continuity check from each of the components to the bundle?
- Have you located the bonding wire near the top of the rudder post?
Although it will certainly be best to bring that Mango back to original condition, but because of all of the other issues with that boat, it is probably impossible to do. It is possible that you will want to consider locating zincs in a different location than the rudder, but I believe that the quadrant and rudder post should be connected to the bonding system.
Regarding the hole next to the SSB grounding plate, I believe that this is part of the rudder hinge bracket, and that there was something through that hole securing the rudder hinge. Several questions come to mind about this missing attachment item, but the most serious is how well is that rudder attached and has water penetrated the skeg? Have you tested for moisture on the skeg?
I wish you the very best in the restoration of this once proud Mango and hope that you can get all of your issues behind you.