13
BONDING
SYSTEM
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The purpose of the Bonding System is to
protect your yacht’s underwater compo-
nents from electrolysis and galvanic corro-
sion. Examples of underwater components
would be the propellers, propeller shafts,
rudders, engine/generator seawater intake
valves and any other metallic parts that may
come in contact with seawater.
Electrolysis and galvanic corrosion occurs
primarily in salt water, but can occur to a
lesser degree in fresh water. Salt water
allows electric current to fl ow from anodic
to cathodic material. Any two metals from
two components and their relative positions
in the galvanic rating table will determine
which metal loses material (anode) and
which metal remains largely undisturbed
(cathode). The distance apart on the gal-
vanic table of the two metals determines
the rate of wear. To help prevent corrosion,
sacrifi cial zinc anodes are fi tted to the un-
derwater components of your yacht, such
as the propeller shafts and rudders. A large
sacrifi cial zinc anode plate is also attached
to the underwater area of the transom (See
photographs on Page 19 and 20, which
illustrate the location of the zinc anodes).
The purpose of these sacrifi cial zinc an-
odes is to attract any destructive electrical
currents away from the metallic underwater
components, thereby preventing their even-
tual corrosion and allowing the corrosion of
the sacrifi cial zinc anodes. The sacrifi cial
zinc anodes are considerably easier and
cheaper to replace and their deterioration
will not affect the performance of your yacht,
as would the deterioration of a propeller or
rudder.
The Bonding System is a network of wires
(color coded green) that are connected to
all metallic underwater components within
the interior of the hull, which makes them
one unit for electrical current purposes. This
network of wires is then attached to the
sacrifi cial zinc anode located on the tran-
som, which allows corrosion of the anode,
but prevents corrosion of the underwater
components.
General maintenance of the Bonding
System consists of yearly replacement of
the sacrifi cial zinc anode located on the
transom and all other zinc anodes located
on the propeller shafts, rudders, etc. and
should be completed during the spring
launch procedure. The anodes may require
more frequent replacement, depending on
your docking location and the length of
your boating season. If possible, check the
anodes for excessive corrosion midway
through your boating season. If excessive
corrosion is noted, have your dealer or a
competent technician replace the sacrifi cial
zinc anodes. Periodically check the wiring
connections to make sure they are tight and
free of corrosion. Tighten and clean connec-
tions as necessary.
NOTE: Silverton recommends placing
sacrificial zinc anodes on the following
components:
• Propeller shafts
• Rudders
• Trim Tabs
IMPORTANT: DO NOT paint any of the
sacrifi cial zinc anodes as it will retard the
fl ow of electric current through them and
render them ineffective.
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