Posted by sierrasmith71 (sierrasmith71@…>)
My freedom 21 hull number 234 has the mast connected to the keel
bolts with a # 6 wire (heavy)
Anyone else have this connection?
This does present a problem as the lead keel seems to be not
insulated from the water, as I imagined it was fully encased it
fiberglass… I tested it this afternoon by putting a copper wire
over the side {salt water} (with the end stripped of insulation) and
measured the voltage (with a high input impedance DVM) from the wire
to the keel bolts; it was an initial .330 volts and dropped slowly
to .22 volts after 2 hours. I guess the volt dropped as the copper
corroded (it was dull colored when I removed it.)
The problem is that I am installing shore power 120VAC wiring and I
have the AC ground connected to the DC system ground. The DC system
ground is connected to the mast through the shield of the VHF
antenna I installed this Spring (I screwed the antenna mount to the
mast top)— I verified this connection with an Ohm meter.
So it all means that when I hook up the AC to shore power The shore
power AC will be grounded thru the keel to the water and a scenario
is in place for galvanic corrosion with other near by boats that are
also connected to shore power. A solution of course is to install a
galvanic isolator in the AC wiring…more money.
The question is do I cut the mast to keel connection and save some
money or keep it and hope that it provides a degree of protection
from a lightning strike and install the isolator??
David Garrison
Freedom 21 #234 “Jellyrum”