Fire system- The argument for a fixed system on a sailing boat

by Canadian Yachting/Sail-World Cruisin on 20 Dec 2010 Engine room fires are mercifully rare on sailing boats, but every so often, one does occur. The engine room is the most likely place on your boat for a fire to get started and if the fire breaks out while you are out on the water, the lives of everyone on board are at risk.

While data on fires in engine rooms is not well kept around the world, the US Coast Guard estimates that 90% of all fires on a boat occur in the engine room. It is easy to see why. The engine room has the engines, the fuel and the electrical systems all in a confined area; this is also where the heat and vibration are generated. Screws, clamps and fittings are most likely to work loose in the engine room.

Then, a spill and a spark is all it takes.

If a fire occurs when the boat is unattended or in storage, the danger to human life may be less, but the property damage could be dramatically greater. Consider the liability if it's your boat that initiates a fire that takes down a storage building of other yachts.

Most sailing countries require that hand-held fire extinguishers are carried on board. Usually, depending on the size of your vessel, you are required to have one of two classes of fire extinguishers, one for combustible liquids (such as gas and oil); and one for electrical fires.

The best bet, of course, is to have one that will cope with all classes of fires.

If one is only required to have portable extinguishing systems on board, why would a person want an inbuilt system?

The key point is that the built-in system offers 24/7 unmanned protection. If such a high proportion of fires start in the engine room, then the safest and fastest way to combat an engine room fire is with a fixed system.

As a general boating writer and boat reviewer, I regularly explore engine rooms on new yachts. Sometimes just getting the hatch open and getting down to the engine room bilge can take several minutes.

A built-in system delivers the fastest response and will probably help to minimize property damage and human risk in the event of a fire. And yes, I know of at least one new boat that caught fire. 'New' is no guarantee of safety.

Without a built-in system, when a fire is discovered, the skipper or crew must first locate the portable extinguisher, move to the point of the fire, in the case of an engine room, open the hatch or doorway (which incidentally allows in more oxygen creating a larger fire), then point the dry chemical extinguisher at the base of the fire, discharge and hope for positive results.

The diesel fuel on a sailing boat is safer to handle than gasoline, but in all cases opening the hatch when a fire is burning will add enough new oxygen to create a real danger of explosion and high chance of human injury.

A built-in system is usually not required until a boat is over around 65ft, and larger boats which carry passengers are required to have them. However, it is highly recommended that all boats with inboard or stern drives should have a fixed fire extinguisher system.

One built-in system that I have seen recently just makes so much sense. It has a built-in system and engine hatch sight glass.

The built-in fire suppression systems can be activated either manually or automatically. All have a tank that can be located somewhere in the engine room area (according to the manufacturers specifications) and these extinguisher tanks automatically discharge their fire suppressant at a pre-set point. For instance, the Fireboy system automatically discharges when the temperature reaches 175 degrees.

The suppressant 'smothers' the fire with chemical or gas that will not support combustion. Then the diesel engine will require an automatic engine shut down. A diesel engine will not automatically stall with the introduction of the fire extinguishants; a separate system is required to stop the diesel, otherwise it will simply consume the agent and continue running.

Some time ago, these built-in fire suppression systems used Halon gas but it was discovered that Halon was very damaging to the environment. The signing of the Montreal Protocol included the ban on Halon. It became effective in 1994.

Fireboy elected to cease the sale of Halon systems at that time. Recycled Halon was allowed to be sold, but there was to be no new Halon manufacturing. Europe moved quickly to ban Halon, and in the USA, effective on January 1, 2007 new boats could not be equipped with recycled Halon systems either.

Other substances were developed and now chlorotetraflkouroethane and heptaflouropropane are used instead; both chemicals are manufactured by DuPont Chemical. Chlorotetrafluorethane FE241 has an ozone depletion potential (ODP) of .02. FE241 is not permitted in Europe and several other countries.

HFC-227ea Heptafluoropropane has an ozone depletion potential of zero. Additionally, HFC-227ea is approved for use in occupied/manned spaces. FE241 and HFC-227ea are non-corrosive and non-conductive. When the clean agent system discharges there is no residue, or powder substance to clean up. It does not affect electrical or mechanical equipment.

An alternative system uses ultra-fine, potassium-based aerosol. Space and weight requirements are minimal and, in many applications, the small size of systems like the Nautical Fire Suppression Stat-X aerosol generator makes them the only viable option. A low installation cost makes them an acceptable fire protection solution.

Another question is how to properly size a fixed fire extinguisher system. The answer is that the cubic volume of the protected space must be calculated (length x width x height). Your system supplier will advise you. Further information on various systems available can be obtained from your local marine supplier, or you can contact a supplier online eg., http://www.fireboy-xintex.com!Fireboy.

Odds are that you'll never experience an onboard fire. But, it doesn't take much imagination to see the benefit of having a system on your boat!

For information about how to avoid fire on your sailing boat, see previous http://www.sail-world.com/CruisingAus/index.cfm?SEID=0&Nid=48421&SRCID=0&ntid=39&tickeruid=0&tickerCID=0!Sail-World_article.