I guess this looks like the rudder holder plate bolts passage on the Maramu
check picture attached - taken when rebuiding the rudder last year.
on the Maramu the anodes are on the rudder, continuity copper wires are running down the outer part of the skeg linked to the rudder bolts by tin weld; goes thru holder plate into the rudder blade to the anodes bolts.
even though different breed, hope this helps.
christian alby - Désirade VIII Maramu #116 now in Port Leucate
Christian Alby - France home fixe +33 (0)5 34 39 06 02 home Internet +33 (0)9 60 37 22 72 mobile +33 (0)6 42 69 07 80
I believe that there have been many modifications to that Mango. I seem to remember a late model Mango that had the zincs on the rudder like Santorins, SMs, 54s, 55s, and 64s. I am not sure of the position of early model Mangos. Hopefully a Mango owner can give you a clear answer for hull #60.
The most important issue regarding the zincs and the bonding system is: does the zinc electrically connect with no resistance to the bonded items? Have you checked continuity between the zinc and the engine propellor shaft? What about inside the area of the rudder post/quadrant? Is there evidence of the bonding wire connecting to the rudder post or quadrant? This connection the the rudder post/quadrant is what you should see on the above mentioned models. Unrelated to your direct question, but significant because of the potential modifications on hull #60, is this: Is there a weep hole in the bottom (underneath) of the rudder?