
fire on
board
by RICHARD BROWN

Of all the horrors that may
afflict the small boat sailor, fire at sea must be one of the worst.
The progressive changes in the materials from which boats are made and
equipped has gradually increased the potential for a serious fire to
the point where a modern yacht could be regarded as a floating
incendiary bomb. That view may seem melodramatic, but plastic hulls
and liners with wooden trim are readily flammable and they are then
filled with plastic foam cushions, synthetic fabrics, liquid petroleum
gas (LPG), fireworks (flares), petrol or diesel fuels, perhaps
paraffin for cooking, heating or lighting, paints and solvents, and an
ever growing range of electrical equipment.
Possible sources of ignition are the engine, the electrics,
cooking and heating with naked flames, gas refrigerators, and smoking.
Additionally, there are the natural phenomena of lightning and static
electricity.
The potential for a fire is very real, but fortunately they are
fairly infrequent, which is undoubtedly due to both good management by
skippers and crews, and good luck.
Fire prevention - installations
Fire prevention must begin with
the builders of the vessel, for they are responsible for the
installation of the engine, fuel tank and pipework, the electrical
systems including wiring, and the cooking and heating arrangements. It
is interesting to reflect that unsinkability is now being made a
selling feature for yachts, but fire resistance (apart from hull
materials like metal or ferrocrete) is never advertised. Yet the risk
of fire is probably greater than that of being seriously holed.
Details of correct installation of the above facilities would take
up several articles, but the following points should be considered:
Fuel
Petrol has a much lower
flash-point than diesel, but if it is kept in secure, leak-proof tanks
with on-off taps it cannot catch fire. Because diesel does not ignite
as readily as petrol, it is tempting to regard it as safe and become
careless, but remember, once ignited diesel burns fiercely.
The fuel tank should be situated well away from the engine and
exhaust pipe. The tank must have a vent pipe which exhausts on deck or
overboard to ensure that any fuel vapour is discharged safely. Metal
exhaust pipes must be well lagged, particularly where they pass
through bulkheads and if the exhaust pipe has to pass near the fuel
tank, fire proof thermal insulation should be used to prevent heating
of the fuel. The fuel feed pipe to the engine will be subject to
considerable vibration which could fracture it in time. The pipe must
be of adequate material and well secured. Plastic tubing should not be
used for flexible fuel lines as it will rapidly melt and feed an
engine compartment fire with fuel. Special purpose flexible pipes are
readily obtainable.
A drip tray placed under the engine and gearbox will prevent
leaking oil and fuel from accumulating in the bilges and is easily
wiped clean at regular intervals.
Gas
The gas bottle should be located in
a separate compartment well away from the engine, electrics and fuel.
This compartment should have a drain through the side of the hull
(above the waterline), so that any leakage from the on-off valve or
regulator will drain safely overboard. The gas supply line should be
correctly installed to minimise the possibility of damage. Any
flexible connection to the cooker, especially if the cooker is
gimballed, should be inspected very regularly for signs of damage,
slack connections or wear. British Standard BS 5482 Part 3 is a Code
of Practice for Domestic Butane and Propane gas burning installations
in boats, yachts and other vessels.
Electrics
The electrical supply systems
should have isolating switches at the batteries. The wiring should be
properly insulated and of more than adequate current carrying capacity
for each circuit. Every circuit should be separately fused with a fuse
of the correct rating for the normal current taken by the connected
equipment.
All installations should be thoroughly checked at every
opportunity for signs of damage: dents; cracks; chafing; etc. Do not
forget to inspect the stove mountings, more than one stove has been
known to come adrift in a rough seaway.
Fire prevention - good
housekeeping
Fuels and bottled gases are safe
if handled correctly. Follow a set drill for refuelling: Stop the
engine. No smoking. Turn off the cooker, heater and any gas pilot
lights. Switch off all electrics. Watch the fuel delivery pump gauge
to check that the amount being supplied to the boat's tank does not
exceed the available tank capacity. In warm weather allow space in the
tank for the expansion of cold fuel.
After refuelling allow time for fumes to disperse and ventilate
where possible before restarting the engine or relighting pilot lights
etc. Gas leaks frequently occur after connecting a fresh cylinder, so
it is advisable to regularly change the sealing washer between the
bottle and regulator.
Gas connections can be tested with soapy water. If a regulator
develops a fault, do not attempt repairs. Leave it to the experts.
It is very sensible to install a gas 'sniffer' alarm as LPG is
heavier than air and if spilt from a cooker or a faulty connector, it
will descend into the bilges. Modern diaphragm bilge pumps are also
very effective air pumps and they can be used to pump gas or fuel
fumes out of the bilges. Daily pumping of the bilges, even if dry, is
thus a sensible routine. Modern gas stoves have low flame 'clicks' and
flame blowout sensor/cutouts to reduce the possibilities of gas
getting into the bilges.
For lighting gas cookers I much prefer a good quality piezo-electric
lighter. Mine has been very reliable, it does not need batteries and
unlike matches can be used one handed, leaving the other hand free to
control the gas tap or to hang on with if conditions are rough.
The gas supply should always be turned off at the bottle when it
is not going tobe used for a while and when leaving the boat
unattended.
The hazards of smoking are well known. If possible do not permit
smoking other than on deck and certainly do not allow lighted
cigarettes to be left unattended or permit smoking by a crew member
who is lying in a berth.
Never refill paraffin heaters while they are hot. It is better to
have the inconvenience of a short wait while they cool than risk the
new fuel flaring up in your face.
The deep fat frying of chips is hazard enough in the home, let
alone on a yacht. This skipper has to frequent ports with good chip
shops to avoid this risk (and mutiny by the junior crew).
Spare cans of fuel should be stored in similar compartments to
that of the gas bottles. The cans should be in good condition and it
is advisable to check that the filler caps are sealing properly before
stowing them. The new plastic cans complying with SI 1982/630 seem
ideal for marine use, as they are light and won't rust.
Extinguishing a fire
On board a yacht the range of
fire fighting equipment is usually limited to a couple of
extinguishers, buckets of water and perhaps a small fire blanket. Each
can be extremely quick and efficient if used correctly, but it should
also be remembered that a fire can be stopped by removing the source
of fuel (e.g. turning off the petrol), providing that the necessary
tap or switch can be reached without further endangering life.
Fire extinguishers. There are many types on sale, but those
recommended for small craft are filled either with dry powder or a
liquid halon (BCF or BCM).
Dry powder is effective on all types of fires, but has the
drawback of being very messy to clear up afterwards, its use being
like an explosion in a talcum powder factory. Through checking the
contents of the dry powder extinguishers fitted to my own boat, I have
found that the powder has a tendency to agglomerate into soft lumps,
which I am worried might severely impair the performance of the
extinguisher, even if they did not block the discharge nozzle. These
lumps have been found to begin forming in as little as a couple of
months afloat and I am now rather dubious about the suitability of dry
powder extinguishers for use on small craft, unless checked or
serviced at least every season.
BCF (bromchlorodifluoromethane), or the less common BTM (bromotrifluoro
methane) can also be used on all types of fires and is astonishingly
effective. Since BCF evaporates it leaves no mess, but it does have
the disadvantage that the fumes are toxic and should not be inhaled.
This could be a problem in a confined space, but the fumes are heavier
than air and will sink to the bilges, whence they can be pumped out.
BCF is ideal for flooding an engine compartment fire, but remember to
switch off the exhaust fan, if one is fitted.
Water can be applied from an extinguisher, a pump or a bucket.
Water filled extinguishers, while very effective, are large and heavy
and therefore not very suitable for stowage and use in small craft. It
is unusual to find a yacht with a pump rigged for fire fighting,
although it would be very easy to do, using a modern bilge pump in
reverse. This could give a discharge of about 8-10 gallons per minute,
which would probably match the performance of a bucket wielded by a
desperate yachtsman.
Water must NEVER be used on a fire
involving petrol, diesel, paraffin or oil, because not only will it
not extinguish the fire, but it will increase its severity several
fold. Having seen it demonstrated on several occasions, I can assure
you the effect is spectacular and frightening, with the height of the
flames increasing instantly by four to five times. There is a high
risk of electrocution if water is used on electrical fires of mains
voltage or higher, until the electricity is switched off, but at the
12 volts used on most yachts (unless connected to a marina mains
supply), there is little danger. Water is probably best used as a back
up to the fire extinguishers and to cool down the burnt area when the
flames have been put out.
Fire blankets are ideal for smothering blazing frying pans.
Small glassfibre blankets are now available for under £10 and are well
worth installing in the galley area.
The Department of Trade(UK) recommend that a minimum of two 1.4kg
(31b) extinguishers are carried on small vessels (up to 9 metres) with
auxiliary engines. Extinguishers should be sited within easy reach at
any time, preferably with one close to the main hatch where it can be
reached from inside or outside the cabin, one close to the engine, and
one at each either hatch or cabin. No individual extinguisher should
have a capacity of less than 1kg.
If you ever have to use an extinguisher, remove the safety
devices, then aim the discharge nozzle at the seat of the fire from as
close a range as possible before pulling the trigger. Do not aim over
the fire, but try and put the fire out from front to back. The sizes
of extinguisher recommended can be used in one hand with the arm fully
extended and if necessary the other arm can be used to shield the face
from the heat of the fire. Attack the fire from a direction which will
leave a safe escape route if you are not successful in putting out the
fire. Continue using the extinguisher until well after the visible
fire has gone in case the residual heat re-ignites it. The residual
heat can be totally removed by damping down with water.
Fire extinguishers have a very short discharge time (10-15 secs)
and it is well worth practising with one on a controlled fire. This
would also ensure that they are tested and refilled from time to time,
say every 3 or 4 years.
Action in the event of
fire
-
Treat any fire very seriously no
matter how small. Any fire can get out of hand very
rapidly.
-
Alert all on board and tell them to
get on deck. Count heads.
-
Attack the fire at once with an
extinguisher.
-
If fuels or electrics are involved,
detail one crew member to turn them off at source, if
possible.
-
Close fore hatches and ventilators to
reduce through draughts. Shut off engine compartment
ventilation fans.
-
If you can transmit either by radio
or visually, inform the nearest Coastguard station or
other vessel of your problem. (An alarm call can always
be cancelled, but there might be only once chance to
send it.)
-
Prepare to launch the dinghy or life
raft with lifejackets and emergency survival kit ready
i.e. flares, water, etc.
-
If possible get the crew to alter
course or stop the vessel to prevent the wind fanning
the fire.
-
Think about your own possible
reactions to fire on board. Make sure you and your crew
read and learn the operating instructions for your
extinguishers. Keep all equipment in good order. A few
minutes planning and practising your fire drill could
save life and your vessel when every second counts.
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