Fish Zincs, Pencil Zincs and stray current

[gcalahan]

Hello,

Regarding Fish zincs, pencil zincs and stray current. The PO of this boat installed a fish zinc and for three years I have left it hanging from the shroud. It has not "sacrificed" anything in the last three
years. Would this tell me my shrouds are not grounded? Last year I
rebuit the 2" heat exchanger on my '84 M-25 and , of coarse replaced
the zinc. So as a result of this thread checked my own pencil zinc
and it is gone. Well, today I checked for stray current in the water
and dropped a wire off boat into the water and put my multimeter on
DC volt and went to the motor block. I am showing .23-.24 v.
Interesting....Should the green wire ground)of the AC (shore Power)
go to ground of the battery banks?? I haven't checked if that is the
way my boat is wired or not yet. After 3 years, I am still finding
oddities from the PO. Could it be just stray current from other
boats in the marina? My shaft zinc does not seem to have a short
life. I am also in brackish water, not salt water.

Any thoughts??

Gary Calahan
"O'Calahan"
'84 STFK