Chapter 4: The Legal Requirements of Boating
Fire Extinguishers

Extinguishers are classified by a letter and number symbol. The number indicates the relative size of the extinguisher, and the letter indicates the type of fire it will extinguish.

• Type A fires are of combustible solids like wood.
• Type B fires are of flammable liquids like gasoline or oil.
• Type C fires are electrical fires.

All vessels that allow explosive or flammable gases or vapors to be trapped must carry on board a U.S. Coast Guard–approved Type B fire extinguisher(s).

Approved types of fire extinguishers are identified by the following marking on the label—“Marine Type USCG Approved”—followed by the type and size symbols and the approval number.

Use this chart to determine the type and quantity of fire extinguishers required for your vessel.

Extinguishers should be placed in an accessible area—not near the engine or in a compartment, but where they can be reached immediately. Be sure you know how to operate them.

Fire extinguishers must be maintained in usable condition. Inspect extinguishers regularly to ensure the following.

• Seals and tamper indicators are not broken or missing.
• Pressure gauges or indicators read in the operable range.
• There is no physical damage, corrosion, leakage, or clogged nozzles.

Fire Extinguisher Charge Indicators

Check the charge level of your fire extinguishers regularly. Replace them immediately if they are not fully charged.

To check this style of extinguisher, depress the green button. If it is fully charged, the green button should pop back out immediately.
On this style of fire extinguisher, the needle indicator should be in the "full" range.

Remember—Keep bilges clean and free of trash in order to reduce the risk of fire.

Backfire Flame Arrestors

Because vessel engines may backfire, all powerboats (except outboards) that are fueled with gasoline must have an approved backfire flame arrestor on each carburetor. Backfire flame arrestors are designed to prevent the ignition of gasoline vapors in case the engine backfires.

• Backfire flame arrestors must be:
  • In good and serviceable condition
  • U.S. Coast Guard–approved (must comply with SAE J-1928 or UL 1111 standards)
• Periodically clean the flame arrestor and check for any damage.

Ventilation Systems

The importance of ventilation is crucial. The purpose of ventilation systems is to avoid explosions by removing flammable gases. Properly installed ventilation systems greatly reduce the chance of a life-threatening explosion.

• All gasoline-powered vessels, constructed in a way that would entrap fumes, must have at least two ventilation ducts fitted with cowls to remove the fumes. At least one exhaust duct must extend from the open atmosphere to the lower bilge. At least one intake duct must extend from a point at least midway to the bilge or below the level of the carburetor air intake.
• If your vessel is equipped with a power ventilation system, turn it on for at least four minutes after fueling and before starting your engine.
• If your vessel is not equipped with a power ventilation system (for example, a personal watercraft), open the engine compartment and sniff for gasoline fumes before starting the engine.

Vessels built after July 31, 1980, which contain power exhaust blowers in gasoline engine compartments, must have the above warning sticker placed near the instrument panel.

Mufflers and Noise Limitations

All vessel engines must be equipped with an underwater exhaust system or effective muffling device.Vessel operators may not hear sound signals or voices if the engine is not adequately muffled.

• Motorboats and PWCs may not emit noise in excess of 86 decibels measured at a distance of 50 feet. At “idle speed,” exhaust noise may not exceed 90 decibels when measured by a sound meter held one meter (about three feet) from the muffler.
• More restrictive noise standards are in effect for Flathead Lake (Flathead and Lake Counties), Echo Lake (Flathead County), and Swan Lake (Lake County) in northwestern Montana because of population density and heavy recreational use. On these waterways, noise near the shoreline may not exceed 75 decibels.
• Certain exceptions are made for state-sanctioned regattas or boat races and by special permit.

Vessel Safety Checks

The U.S. Coast Guard Auxiliary and U.S. Power Squadrons will perform a Vessel Safety Check (VSC) of your vessel and equipment free of charge. This inspection covers federal and state requirements. If your vessel meets all VSC requirements, you will receive a VSC decal. If your vessel fails to meet all requirements, no report is made to any law enforcement agency.