How to Handle (And Not Handle) Spilled Gasoline
Whenever gasoline is spilled in the bilge, anything more than a few dribbles, the response should always be to call the fire department. With the boat shown burning above, the new owners had refueled the empty tank from a portable gas can and got the engine running. The following morning, they returned to find about 20 gallons of gasoline had somehow found its way into the bilge. According to a bystander, the boat ‘reeked’ of gasoline. He said the owners of nearby boats were all nervous.
Instead of calling the fire department, the owner called a mechanic. The latter shut off the electrical switch and began mopping up the gasoline. As he was finishing, something—maybe static electricity or the bilge pump clicking on—caused an explosion. Two people had to be airlifted to a hospital with severe burns. A third person was treated and released. By the time the fire was extinguished, five boats had been destroyed and three others were damaged.
Unlike mechanics, professional fire fighters are trained to deal with spilled fuel. According to Kenny Athing, a technician with the Fairfax County, Virginia Fire and Rescue, fire fighters would have handled the same situation by boarding the boat (in full protective gear), to assess the situation. Like the mechanic, they would shut off the battery switch to reduce the chance of sparking. Unlike the mechanic, they would have filled the bilge with foam to suppress the explosive vapors. The boat’s owner could then have contacted a private salvor to clean the foamed gasoline. The latter often will often have a compressed air pump to safely remove the gas/foam mixture.
Your Boat’s on Fire… Now What?
Using the Wrong Type of Extinguisher to Fight a Fire is Like Trying to Dig a Hole With a Rake…
Claim #9702081C: The owner and his two friends were nearing the last leg of a long trip from Yorktown, Virginia to Watkins Glen, New York aboard a 46’ sportfisherman that he’d bought barely three weeks before. They were making good time across Oneida Lake when one of the crew left the flybridge to go below. He quickly reappeared on the flybridge: "We've got a problem," he informed the captain, " smoke!" The captain immediately brought the engines to idle and one of the crew tried very briefly to extinguish the fire. Within a minute or two, he was overwhelmed by fumes and had to abandon the effort. After trying unsuccessfully to send out a Mayday on the VHF, the captain ran to the foredeck, set an anchor, and hailed a passing boat by waving a life jacket. Meanwhile, a volunteer fireman saw the smoke from shore and dispatched a fireboat. By the time the fire was brought under control, the boat was destroyed.
Nowhere to hide but over the side. On board fires can quickly rage out of control if the crew doesn't respond immediately with the correct extinguisher. All hands had to abandon ship when this engine compartment fire became too intense for a portable dry chemical extinguisher to tame. Claim #9807387C
Later investigation determined that the electrical panel was the source of the fire. The captain's urgent Mayday call conveys the danger of all fire outbreaks on boats. Unlike fires ashore, where there are usually several escape routes to safety, there are few places on a burning boat to hide from the heat and noxious fumes. Add to that the anxiety of standing above many gallons of explosive fuel and the choice to stick or swim (literally) becomes even more, well, problematic.
Time is critical with any fire, but when one occurs in the confined spaces of a boat it is imperative that every move made by the crew be the correct move?there is rarely, if ever, a second chance. BoatUS Marine Insurance claim files consistently confirm that a crew that reacts initially with confusion and indecision is likely to panic as the fire spreads.
Success and failure depends on understanding the fundamentals of fire classification, and providing the most efficient fire extinguishers in the locations where they are most likely be needed.
The Fundamentals: Learning Your ABCs of Fire Classification
Not all fires should be treated alike. The source and location of a fire will determine which extinguishing agent should be used for maximum effect. Many people learn at home, for example, that throwing water on a stove-top grease fire (Class B) will cause a violent spattering reaction and spread the burning grease elsewhere. Matching the agent to the fire begins with an understanding of how fires are classified:
- Class A fires consist of all combustible solid materials, such as paper, wood, cloth, rubber, and many plastics including the fiberglass reinforced plastic used for decks and hulls.
- Class B fires consist of all flammable liquids, including stove alcohol, grease, gasoline, diesel, kerosene, oil, oil based paint, teak oil, paint thinners, acetone, varnishes, and flammable gases or fumes.
- Class C fires consist of energized electrical equipment. Class C fires are identified for their potential to electrocute or shock personnel if conducting water-base extinguishing agents are applied. Turning off the electricity will change the status of a Class C fire to a Class A and/or B fire.
Note that Class A, B, and C categories are not subdivided any further, so it may be easier to think of them as (A) solids, (B) liquids, and (C) electrical fires; there's no need, for example, to waste time distinguishing between alcohol or kerosene when your stove’s on fire.
The In's & Out's of Portable Fire Extinguishers
All fire extinguishers are rated according to the extinguishing agent's effectiveness in controlling one or more classes of fire. For example, ABC-rated extinguishers, commonly called multi-purpose or tri-class extinguishers, are capable of fighting all three classes of fire. Numbers preceding the letters (on portable units only) indicate an agent's relative effectiveness in extinguishing that particular class of fire. For instance, a 10 BC dry chemical extinguisher is twice as effective in putting out a fire as a 5 BC unit. Multi-purpose 1A-10 BC dry chemical extinguishers are becoming more popular as an alternative to the common 10 BC extinguishers because of the additional Class A rating, especially since the additional cost is minimal (less than $5).
In general, dry chemical extinguishers, which use a chemical powder to smother the source of the fire, are the favored choice in the boat’s cabin. Not only is a dry chemical extinguisher more effective, it is easier for an inexperienced user to direct the discharge plume to the base of the flame from a safe distance. Conversely, extinguishers with gaseous agents (CO2, Halon, and Halon replacements FE-241 and FM-200), which react with the surrounding oxygen, aren’t as effective in a cabin because the gases are often dissipated before the fire is extinguished.
The ABC units have the drawback of often ruining equipment, but because the priority is on safety and the overall effectiveness of the extinguishing agent, the American Boat & Yacht Council (ABYC) recommends that ABC multi-purpose extinguishers be used in most instances on boats under 65'. The ABC extinguishers not only reduce confusion about what to use and where (saving time), but also cover the possibility that, for example, any Class B fire that spreads from the stove to the curtains (Class A) can be fought with the same extinguisher.
A Subtle, but Costly, Distinction
A 42' powerboat was cruising offshore when a crewmember reported a strange smell coming from the engine compartment. The owner grabbed a dry chemical extinguisher from the galley on his way to the enclosed compartment, opened the access door, and was immediately driven back by smoke. He tried to direct the stream of dry chemical inside the compartment, but he could not see beyond the smoke to locate the source of the fire. By then the fumes had also engulfed the main saloon and he was driven back. From the cockpit he saw flames coming out of the engine compartment's starboard ventilation ducts, so he directed another dry chemical extinguisher into the duct openings; the fire died momentarily but quickly resumed and grew rapidly. It soon became apparent that the vessel would have to be abandoned. It burned to the waterline. (Claim 9708770C.)
The same dry chemicals that are so effective in a boat’s cabin aren’t much use when a fire breaks out in the engine compartment. The reason has to do with how the two types of fires are fought.
Accounts of engine fires typically began with a warning?a burning smell, a loss of engine power, or even smoke trailing after the boat. If someone then opened the engine hatch to check out the trouble, he or she was usually overwhelmed immediately by flames and smoke. Fires need two things: fuel and oxygen. Opening an engine compartment hatch to look for a fire is like throwing gasoline on hot coals; it fans the fire with a rush of fresh oxygen.
The solution is to leave the hatch closed and fight the fire either with a fixed extinguisher in the engine compartment or with a portable extinguisher discharged through a fire port (a small opening into the engine compartment), which is why dry chemical extinguishers of any class are inappropriate. Blindly spraying a chemical extinguisher through a fire port does little or nothing to stop an engine fire because the chemical isn’t being directed toward the base of the flames. A gaseous extinguisher, on the other hand, extinguishes the fire by affecting the oxygen supply. The same extinguisher that wasn’t effective in the wide-open spaces of a boat’s cabin will be much more effective in a cramped engine compartment.
For this reason, among others, the ABYC recommends that either a portable gaseous extinguisher be provided near (outside) the engine compartment or a fixed gaseous extinguisher be used inside the engine compartment. In the event of a fire, either option eliminates the need to open the hatch.
A few Words of Praise for Fixed Systems in the Engine Room
Overall, the most efficient fire protection system is the safest. Claim files show that the majority of fires begin in the engine compartment for numerous reasons: constant pounding and vibration loosens wiring terminals and causes chafe, engine exhausts fail, water pumps fail, fuel leaks?the list goes on. An automatic system, activated by a rise in temperature, can discharge and extinguish a fire long before any crew can detect a fire and react with a portable extinguisher, which is even more relevant if you sometimes cruise shorthanded. The automatic system kills the fire earlier and minimizes damage. And since Halon and its replacements will not damage internal engine parts, it is often possible, after locating and correcting the problem, to restart the engine(s) after a fire and return to port.
Fire extinguishers are typically the last line of defense when a fire suddenly appears. The first line of defense is knowing how to prevent fires before they occur. In upcoming issues, Seaworthy will take a look at how to prevent fires relating to engines, fuel, exhaust systems, electrical systems, galleys, and other fire sources.