cooking or heating appliances.
Since 2010, CO alarms have a built-in end-of-life alarm that lets you know
with an audible and visual signal when
it’s time to replace it, usually after five
or seven years. The first of these newer
detectors are reaching the end of their
life, so a lot of boat owners will start
hearing the warning chirps that mean
it’s time to replace these alarms. If you
have a detector that’s older than seven
years, replace it.
New boats with accommodation spaces built to ABYC standards
will come with CO alarms installed.
Most boatbuilders who are members
of the National Marine Manufacturing
Association build to ABYC standards.
WHO NEEDS ONE? Unlike CO detectors, smoke alarms aren’t required on
boats. But you should have one, especially
if you regularly sleep aboard or have an
enclosed cabin or engine space.
HOW THEY WORK Smoke alarms use
one of two types of sensors: ionization
or photoelectric. Ionization detectors
are better at alerting to fast fires; photoelectric are best for smoky fires. For
boat use, an ionization or combination
detector is best.
HOW TO USE THEM Smoke alarms
should be placed in the living space
of the boat, but not so close to the
galley that making toast will set them
off. Some detectors have a mute button
that silences them for a few minutes
during minor cooking accidents but
keeps them operational. Detectors can
be hard-wired into the boat’s system
or have a self-contained battery. Newer
detectors have batteries that last 10
years – also the life of the unit. Battery-powered detectors have the advantage that they can operate even with a
dead ship’s battery. Use the test button
monthly to check its operation.
WHAT TO DO WHEN IT SOUNDS
Most people have probably heard a
smoke alarm go off at one time or
another and are pretty attuned to looking around for smoke when it happens.
But smoke detectors often sound before
you can see smoke, so don’t assume it’s a
Because our BoatU.S. Marine
Insurance claim files show that the
majority of fires are in or near the engine
room, it’s the first place to check if you
don’t see obvious signs of a fire. But
beware; opening the engine cover may
allow a smoldering fire to suddenly erupt
when fed with air. Crack the cover and
see if the compartment contains smoke
or even flames. Installing a fire port
allows you to insert a fire extinguisher
in the space and put out a fire without
opening the hatch. Sometimes a smoke
alarm indicates an overheating engine
(the rubber exhaust hose melts) or a hot
electrical wire. Don’t dismiss the alarm
until you’re certain there’s no danger.
There are no UL marine-approved
smoke alarms currently available, so
choose one designed for the RV industry; they’ve been designed to be more
rugged than home units. The box should
say that the detector is built to UL
WHO NEEDS ONE? If you have a bilge,
you probably need one. For the past
few years, the ABYC has recommended
high-water alarms on boats, and new
boats built to its standards will have
one installed. These are simple devices
that typically use a switch to activate an
alarm when water reaches a predetermined level.
Some boats have multiple bilge areas;
it’s best to have a separate bilge alarm for
each area, with a
light as well as an
audible alarm and
a label to indicate
the area involved.
The warning can
give you enough
time to find a
leak before it’s
too late. Some
the switch to
the boat’s horn,
the alarm will
be heard when
HOW TO USE THEM The detector
switch should be located high enough
above the normal level of bilge water
to prevent the alarm from sounding
when the bilge has a small amount of
water easily handled by the bilge pump;
it should be located low enough to
alert you if there’s a real problem. The
same issues that plague bilge pumps
can affect high-water alarms: corroded
wire connections and jammed switches.
While the alarm itself may last indefinitely, float switches need to be checked
at least annually.
WHAT TO DO WHEN IT SOUNDS
First, immediately check the level of
the bilge water, then locate the leak.
According to a recent BoatU.S. Marine
Insurance study, at least a third of
boats that sank while underway did so
because of leaks at thru-hulls, outdrive
boots, or the raw-water cooling system.
Many thru-hulls are in the same place as
the outdrive bellows and raw-water
cooling system: the engine room. Look
Warning signs of
The symptoms of CO poisoning include
headaches, drowsiness, and nausea.
With most BoatU.S. claims, one or
more of these symptoms were present,
but victims didn’t recognize the danger they were in. How much CO is too
much? In parts per million (ppm):
200 ppm – Slight headaches within
two to three hours
400 ppm – Frontal headaches within
one to two hours
800 ppm – Dizziness, nausea,
and convulsions within 45 minutes.
Insensible within two hours
1,600 ppm – Headache, dizziness,
and nausea within 20 minutes. Death
within 30 minutes
3,200 ppm – Headache and dizziness
within five minutes. Death within
6,400 ppm – Headache and dizziness
within one to two minutes. Death in
less than 15 minutes
12,800 ppm – Death in less than
switch to the
alarm will be