Chapter 7
7. If marina moored, contact appropriate personnel if signs of gal-
vanic corrosion appear on your drive system. Ask them to check
for stray electrical current which may be originating from a nearby
vessel’s faulty DC wiring or from a marina dock carrying leaking
marina ground wiring.
GALVANIC/STRAY CURRENT CORROSION
Cause/Observed Condition Corrective Action
Sacri cial anodes consumed Replace anodes when 30%
consumed
Sacri cial anodes not ground-
ed to drive
Remove anodes, clean contact
surface, reinstall, check for
continuity
Loss of continuity between
underwater parts & ground
Provide good ground connec-
tions
Nearby vessel with stray cur-
rent
Contact appropriate personnel
Remove your vessel from water
Paint on drive heavily worn,
exposing more metal
Prime and repaint or install ad-
ditional anodes
Sacri cial anodes painted Remove paint or replace an-
odes
Drive tilted/anodes out of
water
Leave drive down, install ad-
ditional anodes below water
Power trim cylinders only cor-
roded
Provide a good ground to
drive, all parts must be ground-
ed
Corrosion in exhaust outlets Remove deposits
Corrosion occuring a er vessel
is removed from saltwater
Wash exterior and ush inte-
rior with freshwater
Stainless steel parts corroding Clean parts, remove foreign
material, ensure continuity
Underwater drive parts cor-
roded, sacri cial anodes OK
Oxide lm on anode (fresh
water only) Replace anode
Poor Grd. Replace anode
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