Pearson P31-II, Manual

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If lightning strikes , damage to electronic equipment is
likely because of the high voltage, low amperage surge of
electricity. Therefore, all electrical equipment including
the compass must be checked for damage and or changes in
calibration.
CAUTION: IN THE EVENT OF AN ELECTRICAL STORM, DO NOT ALLOW
ANYONE IN THE WATER. HAVE EVERYONE ON BOARD STAY INSIDE
THE BOAT. DO NOT MAKE CONTACT WITH ANY METAL OBJECT
REGARDLESS IF IT IS CONNECTED TO THE LIGHTNING PROTECTION
SYSTEM OR NOT, ESPECIALLY IN SUCH A MANNER AS TO BRIDGE ANY
OF THESE ITEMS.
The operation of the lightning protection system should be
checked every year at the beginning and end of each season
( see section 5.5 for the proper procedure).
5.4
UNDERWATER GALVANIC CORROSION
This condition occurs when dissimilar metals are in physi-
cal contact with each other in a solution (i.e. sea water).
A potential difference exists between the metals which
causes current to flow between them. All Pearson yachts
are designed with metals that are close together on the
galvanic series. Further, all electrically isolated thru-
hulls are eliminated from the bonding system to eliminate a
low resistance path for current. Although careful
consideration is given to design, sacrificial zinc anodes
should be used to protect large submerged hardware such as
struts, shafts, and propellers.
5.4.1 Electrolysis
Electrolysis occurs when direct current forces a metal to
become "anodic". This current may come from a battery or
any other external source, and because these voltages are
much higher than in galvanic corrosion, the corrosion
caused can be rapid.
Zinc anodes may slow down the effects of stray current
corrosion, but this problem may be corrected only at its
source. Most often, stray current can be traced to damaged
equipment, loose and/or damaged wiring, or improperly wired
equipment. In some cases, the stray current may come from
a source external to the boat.