LETTERS TO THE EDITOR
Thanks very much for the note and
for the information on water mist fire
suppression.—Steve D’Antonio
Congrats on a very good article in
PMM. I do feel that the engine room
air exchange rates sometimes prohibit
or delay the accumulation of high
heat, thus prohibiting the timely
activation of the extinguishing
cylinders. This can certainly limit
their effectiveness.
I have written a proposal for
NFPA (National Fire Protection
Association) 302 (annex material)
that recommends engine room smoke
detection in vessels over 40 feet. This
would typically be a diesel-powered
boat. If the engine meets the new
diesel emission requirements, there
should not be an issue with false
alarming. Smoke detection devices
have proven to be more sensitive
than heat detection devices.
There is a five- to 12-year
hydrostatic testing requirement for
fire extinguishers, depending on the
content and construction of the
cylinder. Halogen cylinders must
be tested every 12 years, according to
regulations set forth by the National
Fire Protection Association.
Once again, good work. I enjoyed
your very thorough article.
John McDevitt
Bluewater Yacht Sales
Stevensville, Maryland
Indeed, if the air turnover rate is
high enough, this can be a problem. In
my experience, however, most marine
engine rooms are too hot already, so
getting the temperature to reach
175˚F—the threshold for most
automatic fire extinguishers—in the
event of a fire usually isn’t a problem.
I wholeheartedly support your
proposal regarding a requirement for
smoke detection and encourage every
boat owner to install smoke detectors
aboard their vessels. I include this
recommendation with every consulting
inspection report I write. My
preference is for a wireless system
that causes all smoke detectors
aboard to sound if one detector is
triggered.—Steve D’Antonio
BATTERY CONFIGURATION
I am reworking the house battery
bank on our 48-foot trawler, which
we live aboard full time, and have
some flexibility in how the 12 Group
31 AGM batteries are connected.
What I don’t have is a good
explanation of what would be best,
