Viking VSC 61 FY Owner's Manual page 4

Corrosion Protection - 82
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Running Gear Protection
Corrosion protection for the propellers, shafts and rud-
ders starts with selection of the best components and
materials to stand up to the severe warm salt water envi-
ronment typical of Florida, where unprotected metal is
quickly destroyed.
Prop shafts
Prop shafts are made by Teignbridge Propulsion Group in
Devon, England. They are 60 mm (2.3 in) Temet boat
shafting, precise to a tolerance of 0.003 inches out of
round to reduce vibration when rotating at high speed.
Galvanic corrosion is minimized by use of a specially for-
mulated metal that has a resistance to corrosion superior
to stainless steel – ie., it is below stainless in the active
and passive galvanic charts.
Propellers
Props are also by Teignbridge. They employ nickel-
aluminium and bronze AB2, for high running speed and
corrosion resistance. Props are 5-blade 30x42; shaft
threads are 42x3.Struts attach to the hull with large bolts,
with the nuts torqued down onto copper alloy backing
plates B (also called "P brackets"). Attached to these are
green bonding wires connected to the studs holding the
zinc anodes on the outside of the hull. This affords corrosion
protection to the running gear.
Zinc pencil rods
The MAN diesel engines and the Onan generator each have
internal zincs which MUST be replaced as scheduled – refer
to manufacturers' manuals for details. The ZF marine gear
also has zinc anodes on the oil coolers, near the seawater
inlet and outlet. Check annually or at 500 hours, or if
seawater leakage occurs.
Tides Marine self-aligning shaft seals
These comprise a simple nitrile lip seal on the shaft log
that blocks seawater to keep it from entering the vessel.
It is an important corrosion fighting strategy to prevent
seawater entering the engine room as much as possible.
Bow thruster protection
The Side Power bow thruster has its own protection against
electrolysis and corrosion. A zinc anode forms part of the
attachment nut for the propeller. Check this for erosion
whenever the vessel is out of the water, or have a diver
inspect it when installing main zinc anodes on the hull. Do
not ignore this anode, or corrosion will quickly attack the
thruster and its propeller.
Viking Sport Cruiser 61FY
P brackets,
Struts connect to bonding
through these brackets
Teignbridge prop and shaft
Change internal zinc anodes on schedule
Bow thruster
zinc anode is
part of this nut.
Bow thruster anode
Owner's Manual
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