LETTERS TO THE EDITOR
A voltage drop of about 3 percent,
and certainly no more than 10
percent, is preferred for the alternator
output wiring. Wire sizes can be
calculated using tables and formulas
found in ABYC’s E- 11 “AC and DC
Electrical Systems” guidelines
(available at abycinc.org/standards/
purpose.cfm#E11) and in several
books, including Charlie Wing’s
Boatowner’s Illustrated Electrical
Handbook. The smallest wire that can
be used in any ordinary onboard DC
circuit (other than those inside an
electronics enclosure, for instance) is
16 gauge.—Steve D’Antonio
ENGINE VIBRATION
Steve D’Antonio provided good
advice on the Camano 31/Volvo
vibration problem (“Letters to the
Editor,” PMM Oct. ’08). However, I
may be able to add something to
what Steve wrote. I am the founder of
Camano Marine Ltd. and designer of
the Camano 31. In earlier days, I
personally did the engine installations.
I fully agree with Steve that
finding the source of the problem is
always better than masking it. But,
having said this, I can tell you that
while installing these engines and
subsequently doing sea trials, I
sometimes noticed that vibration in
this speed range (1050–1200 rpm)
was transferring into the boat. This
could be reduced to a large extent
by redistributing the weight on
the four engine mounts. This is
a concept that is not readily
understood and applies to any
engine using these soft mounts.
When adjusting engine mounts
during the process of lining up the
prop shaft to the engine, the
installer is raising and lowering each
end of the engine, as well as sliding
each end from side to side. While
doing this, both a diagonal load
and a side load can be put into the
mounts. For example, if you are
raising the front of the engine by
tightening the front mounts, you do
not raise the tension in the mounts,
since the engine rises instead.
However, if you tighten one
side more than the other, the
tension in that mount increases,
along with the tension or load in
the mount opposite that in the
diagonal direction. For example, if
the front portside mount is taking
more load than the starboard side,
then the load will increase on both
the front portside and the rear
starboard-side mounts.
ECONOMICAL SPACIOUS EFFICIENT GLOBAL INTELLIGENT
FT. LAUDERDALE OFFICE ANNAPOLIS OFFICE
1-888-233-4913
1-800-672-1327
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