Viking VSC 61 FY Owner's Manual page 3

Owner's Manual
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v1.0
The Bonding System
Viking 61FY has a bonding system to protect the vessel
as much as possible from severe electrolytic corrosion of
propellers, shafts, rudders, fuel tanks, etc. caused by
electrical currents and warm seawater. Essential to the
cathodic protection system is an 8 gauge green and yellow
common bonding wire connecting protected components
to two sacrificial zinc anodes, port and starboard under
the hull.
Note:- The bonding wire must NEVER be connected to a
current carrying DC ground.
Metal graphite bonding brushes running on the prop shaft
inside the vessel protect the propellers and shafts by con-
necting them to the bonding system. The brushes must
always be in good firm contact with the shaft, and running
on a clean and shiny part of the prop shaft. If seawater salt
deposits are under the brush there is no protection.
At some marinas metal in the docks and stray electrical
currents in very warm seawater can cause severe corrosion
and vessels normally docked there need special attention.
Inspect zincs regularly and often (once a month may be
necessary in electrically active waters). Shaft zincs are
not recommended.
The vessel bonding system acts to reduce both galvanic
and electrolytic corrosion. These processes, especially in
warm seawater with elevated temperatures, quickly cause
extensive corrosion to any of a vessel's unprotected metal
fittings exposed to seawater.
Sacrificial zinc anodes
Zinc anodes must be replaced once they are half their
original thickness. In Florida they have a short life, but it is
essential they be replaced, or there is no bonding and the
equipment they protect is at risk. Anodes are usually in-
spected and replaced by a diver unless the vessel is out
of the water. Visual inspection should show signs of corro-
sion or pitting – if anode corrosion is not apparent the
bonding system is likely not working and must be inspected
without delay. A simple continuity test inside the vessel
between the prop shaft and the two studs that hold the
zinc to the hull will confirm whether there is continuity.
Whenever the vessel is out of the water for service check
that anodes are not excessively corroded. If corroded, but
not down to half-thickness, they can be somewhat reju-
venated: remove the zincs, clean them with a wire brush,
clean off corrosion on the bolts, and reinstall. Never use
anti-seize lubricants, sealants or pipe dope to install zincs.
This would isolate them electrically from the metal they
protect and corrosion would result. There must be a good
electrical connection to the attaching bolts, which con-
nect to the bonding wire inside the vessel.
Viking Sport Cruiser 61FY
Tides shaft seal
Bonding
brushes
To clean the shaft and brushes . . .
Gently lift the spring loaded brush arms
shaft MUST be clean and free of seawater deposits.
Bonding wire
Bolts must be
kept tight to
protect the
rudder
Zinc anode
81 - Corrosion Protection
Continuous green
bonding wire
A
Tides shaft seal
Rudder bonding
keep
tight
Zinc anode under hull.
There is one port; one stb.
A. The prop