Bringing air conditioning, microwaves, electric heaters, and
other AC appliances aboard makes life on the dock more
comfortable and convenient but also greatly increases the
risk of fire. Most AC electrical fires start somewhere between
the marina pedestal and the shorepower inlet on the boat.
BoatU.S. has long recommended using only marine-grade
power cords with proper adapters and replacing them at the
first sign of wear on the cord or pitting on the blades of the
plug. But the analysis of our fire claims has identified another
high-risk area on boats more than 10 years old: the back of
the shorepower inlet where the ship’s wiring connects to the
terminals. Replacing the shorepower inlet on older boats if it
is original, or at least pulling it out and inspecting the
connections, could well save your boat.
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Wiring harnesses and starters cause a
disproportionate number of fires on boats
more than 25 years old. If you have a
vintage boat and those parts are original,
consider replacing them. Most of these
older boats had relatively simple wiring
harnesses, so if the manufacturer is no
longer in business, or the part is no longer available, a good electrical technician
can put one together for you.
On older outboards, the voltage regulator
is by far the most common cause of fires.
The failure rate increases with age after
10 years, so if your outboard is 15 years
old or more, replacing the regulator may
well keep you from having a bad day on
While loose battery connections, chafed
battery cables, and aged battery switches
can all cause fires aboard, the most
common cause of battery-related fires is
operator error: reversing the battery cables
or connecting them in series when they
should have been in parallel, or vice versa.
If you’re disconnecting your batteries for
any reason, photograph the configuration
with your phone first, label the battery
cables, and mark the positive lug with red
fingernail polish to make sure you avoid a
shocking experience when you reconnect them.
Any interruption of cooling water can lead to overheating and
then to a fire. In this case, a blockage of the raw-water intake
caused the overheating. Other exhaust fires are caused by impeller failures due to age or to sediment in the water. If your engine
overheats, check the engine compartment before getting underway again. Change your impeller every other year, and after a
grounding, or operating in particularly dirty waters.
Cause of fires
that started on the
(excluding off-boat sources)