What type of fire extinguisher is best for a boat?

Club Marine has received about 200 fire-related claims worth over $6m in the last three years. Not every boat fire is as well attended as this recent incident off Perth’s Rottnest Island.

Fire on a boat can be the most terrifying and potentially lethal situation you can face on the water.

Instant terror. Immediate spine-tingling, knee-shaking semi-paralysis that froze me momentarily in place behind the wheel, where I was standing as the outboard well seemed to explode into a wall of flame.

“This shouldn’t be happening,” was my first, useless mental response, before I recovered and darted for the fire extinguisher; that item of safety equipment that had, until now, seemed a legislative necessity rather than an item which might one day save my life.

It was close to midnight aboard my 19-foot half-cab and we were seven nautical miles offshore on a shark fishing expedition. We’d been running a tuna oil slick for several hours and putting loads of tuna and bait fish through the berley bucket. Several smaller bronze whalers had come aboard for tag and release and we’d been busted off by something large a couple of times, so we knew that bigger sharks were close by and had been hoping that a white pointer was in the region.

Not anymore, though. The thought of jumping overboard into that black, oil-slicked, shark-dense water didn’t bear contemplating. Grabbing the extinguisher, I learnt two important lessons in a very short time: firstly, that hand-held fire extinguishers run out very quickly – in fact, surprisingly quickly – and, secondly, that you need to get very close to the fire and accurately direct your extinguisher at the base of it to have any real affect.

As the extinguisher ran dry, I remembered reading an article in a boating magazine that made much of the fact of how quickly a fibreglass boat can burn to the waterline, giving the occupants very little time to react. Adding to my distress was the fact that we were at our ‘secret’ shark fishing spot off a virtually uninhabited shoreline and adjacent to a bush-dense national park. Furthermore, we’d seen no other boats in the area all day.

So the chances of being spotted and rescued were somewhere between Buckley’s and none. Now, rather fortuitously, I suddenly remembered that we always carried a heavy woollen blanket on board as a protection against hypothermia and that wool was supposed to be something of a fire retardant. Moving quickly, my fishing mate and I grabbed an end each and quickly placed it over the flames and packed it down into the well.

Fortunately, the fire was out fairly quickly and although feeling considerably shaken, we were okay and retired to the small cabin for a stiff drink. I’d lost immediate interest in further fishing and decided to wait for daylight to determine the cause of the fire.

It turned out that the fuel hose from the bulb used to prime the outboard had developed some minor cracks, so when we attempted to prime the engine to start it, some fuel escaped into the outboard well. An errant spark as the engine started ignited the spilt fuel and we were suddenly confronted by one of those situations that every boatie dreads. We were lucky. Each year, boating fires and explosions injure a considerable number of recreational boaties and cause millions of dollars in property damage.

There seems to be a certain amount of denial among recreational boaties about the likelihood of a fire happening on their vessel. But, as Phil Johnson, Club Marine’s National Claims Manager, says, this is one issue that no one can afford to be complacent about.

“Club Marine has received about 200 fire-related claims worth over $6m in the last three years. Fire is such a serious issue,” Phil says, “people really need to be more aware about how a fire can occur and what they can do to prevent it.”

As Johnson says, while the risk is very real, many of these incidents could have been prevented or at least had the resultant damage minimised.

FIRE FACTORS

There are many factors that can have an influence on boat fires, beginning with the materials used to build a vessel. A steel boat has the greatest chance of surviving a fire as steel obviously doesn’t burn and won’t melt until it reaches a temperature of around 1538°C, while aluminium comes in second in terms of heat resistance, needing around 660°C before it begins to melt.

Fibreglass composite and wood are the construction materials least able to resist burning and have combustion temperatures of around 260°C. Therefore, craft built from these materials require the best possible fire detection, prevention and extinguishing systems in order to minimise the chances of catastrophic damage.

Newer boats are built using various fire-resistant materials, but older craft often do not have the benefit of these materials, which literally can add more fuel to the fire.

Fire Basics

A fire needs three elements to keep burning – fuel, heat and oxygen. If you remove any one or more of them, it will go out. Simply put, with a fuel fire – if possible – you should turn off the gas orpetrol/diesel supply and/or remove combustible material. Heat can be counteracted by applying cold water and, perhaps most importantly, you can smother fire by cutting off the oxygen with an extinguisher using CO2, dry powder or foam.

Types of extinguishers

Every boat heading out on the water should be equipped with a fire extinguisher and, indeed, most states have laws mandating fire extinguisher fitment to boats.

There are four types of fire extinguishers approved for boats: Foam (AS1841.1 and AS1841.4); Powder (AS1841.1 and AS1841.5); Carbon Dioxide (AS1841.1 and AS1841.6) and Vaporising Liquid (AS1841.1 and AS1841.7). Each is best suited to a particular type of fire. A dry powder extinguisher is a good general-purpose unit that will work well on most fires. It needs to be shaken regularly to prevent the powder compacting, so if you already have one of these, read the maintenance notes and make sure you give it a shake every now and then.

Regardless of the type of extinguisher(s) you have, you should familiarise yourself with their use. Make sure you read the instructions and ensure you can get to them quickly in the event of a fire. Location of a fire extinguisher can have a big impact on the outcome of a boat fire. Automatic systems

The fire-fighting requirements for a small outboard-powered vessel are generally much simpler than those for a larger inboard-powered vessel. To a degree, the complexity increases with size and the larger craft need to have automatic engine room fire detection and suppression systems in place and in good order.

There are a number of these available using various technologies, including CO2, water mist and Halotron. We don’t have enough space to cover these systems in detail, but it’s worthwhile for boat owners to do their own research to determine the best, most appropriate system for their vessel. Surprisingly, even boats in the upper end of the price range are not always well provided for in terms of effective active and automatic systems.

Whatever the particular system you have onboard, it is important to know how it works, what takes place before discharge – which is usually engine and ventilation shut down – and how the system is locally, remotely and, manually activated or overridden.

Causes of fires

It may surprise you to know that over half of the marine fire claims dealt with by Club Marine in the three-year period quoted were caused by electrical problems. Hydrogen gas from batteries, and fuel vapours are also leading elements in boating accidents involving fires and explosions, with fuel being the most common, particularly so when refuelling. It should go without saying that smoking while refuelling is dangerous, as is any other activity that may generate a spark or naked flame.

Petrol vapour is heavier than air, tends to accumulate in the lower sections of a boat and can be difficult to detect. Therefore, a combination of a fitted fume detection device and your own inbuilt one – your nose – should be used. Using a blower to evacuate fumes from your engine room or engine box is good practice, but you should be aware that in the case of a split or worn fuel line, the blower will not be able to stay ahead of the leak. Hence, the emphasis on the importance of detection and in today’s world of ubiquitous and relatively cheap electronic devices, there are even detectors that combine the functions of fume, fire, water and even CO2 detection.

In addition to fume-detecting devices, any vessel on which people sleep should have a smoke alarm installed and it should be checked regularly to ensure correct operation.

Don’t DIY

There are many areas of life where a Do It Yourself philosophy is admirable, but boat electrical systems are not one of them. A considerable percentage of fires can be traced directly to owner incompetence. To quote Club Marine’s Phil Johnson again: “Larger vessel fires from electrical faults are a major cause of concern. Many owners try and cut the cost of installation and repairs by doing this work themselves, only to put themselves and their passengers at risk. They should make sure all electrical work is performed by a licenced electrician. Just because it’s a 12-volt system, doesn’t mean the risks are any less than, say, doing your own electrical work at home.”

Battery charging risks

Charging a boat battery seems, on the surface, to be a simple low-risk exercise, but again, the statistics tell a different story. Club Marine claims data shows that the charging of batteries has been the source of numerous garage fires involving runabouts and smaller fishing boats in which chargers are left connected for long periods of time. The result can be a burnt-out boat, garage or even house. If you are charging your boat battery, you should make sure that you check it regularly, as batteries can get extremely hot while being charged and can become a source of fire. Explosive combinations

Recent publicity surrounding a couple of boating tragedies involving refuelling has drawn attention to the very real dangers inherent in this procedure. Again, Phil Johnson comments: “A lot of the claims for fire occur in inboard ski boats due to fuel vapours or leaks in the bilge of the boat and these tend to occur immediately after refuelling or starting up for the first run of the day. When the boat is started, the starter motor can create a small spark and when it engages with the flywheel, thus igniting the vapours, with explosive results. At Club Marine, we specifically request regular inspection of inboard ski boats to try and avoid this occurring. Over the years, there have been some horrific incidents involving both death and serious injury. We recommend that, before starting your inboard engine, you lift the motor cover and smell for fuel. If there is no smell, you should, nevertheless, start it with the motor cover still up as this can also help avoid a nasty explosion.”

Big bang

To put the very real dangers of explosion into perspective, consider this: one cupful of vaporised petrol in a small space such as an engine compartment, has the explosive power of 15 sticks of dynamite!

Fire prevention

Ideally, with inbuilt fuel tanks, the fuel filler should be located so that spilled fuel is directed outward rather than into the vessel. Portable fuel tanks need to have vents that can be closed off and the tanks need to have a vapour-tight, leak-proof cap. The vent on a portable tank should be open when the motor is running, but when the tank is not in use, the vent and cap should be tightly closed.

Fuel tanks and lines should be inspected regularly at appropriate intervals, as both are susceptible to leaks over time. Aluminium fuel tanks, widely used in boat construction, are some-what susceptible to corrosion. It may surprise boat owners to know that the US Coast Guard regards fuel tanks made from 5052 grade plate with a thickness of 0.09 inches to have an average life of only 6.5 years. Apparently, this thickness is fairly commonly used in US boat manufacturing, but the point is that few fuel tanks can be expected to last the life of the boat. How old is your vessel? When did you last inspect the fuel tank?

Notices should be fitted above gas appliances to remind users to turn off the gas supply when they are not in use and a fire blanket should be kept in the galley, but stowed away from the stove. Rags and materials which have flammable products on them should not be carried aboard. The craft’s electrical system should be well maintained in order to prevent short circuits and sparks. Should a fire occur in a cabin craft, you should never let it get between you and your exit. Survey your purchase

If you purchase an older craft, particularly a larger inboard moored vessel, you should have it closely inspected by a qualified marine surveyor for onboard hazards. This should include all wiring, all through-hull fittings, the battery system, the condition of all appliances and the entire fuel system. Too many accidents occur due to the owner’s unfamiliarity with their new craft and the excitement of trading up or changing from an outboard or stern drive craft to an inboard cruiser can overwhelm good judgement in the rush to experience the new toy.

In the end, it’s all about taking due care and paying attention to the basics. There is no such thing as shortcuts when it comes to fire prevention. You need to make sure that your craft is in good condition, that all the wiring and fuel systems are up to scratch and that, most importantly, your fire-fighting equipment is ready to go. You also need to think about what you need to do in the event of a fire and, even more importantly, you need to educate your passengers about standard fire drills.

Remember, when it comes to fire aboard boats, there are no second chances and, in far too many cases, there is no other craft around to help out.

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