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 are required to have a Type B fire extinguisher(s) on board if one or more of the following conditions exist:

• Inboard engine
• Closed compartments where portable fuel tanks may be stored
• Double bottoms not sealed to the hull or which are not filled completely with flotation material
• Closed living spaces
• Closed storage compartments in which flammable or combustible materials may be stored
• Permanently installed fuel tanks (any tank where the removal of the tank is hampered by the installation of tie-down straps or clamps)

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.

• Extinguishers should be serviced at least every two years. See the label for additional servicing information.
• 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.

Backfire Flame Arrestors

Because boat 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)
• Clean the flame arrestor(s) periodically and check for any damage. The elements must be clean, and the grids must be tight enough to prevent flames from passing through. Use soap and water to clean.

Ventilation Systems

Ventilation systems are crucial. Their purpose 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 in either of these situations:
  • After fueling
  • Before starting the 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.
• Regularly check the ventilation ducts for obstructions, such as nests or debris. Make sure you can feel air coming out the cowl when the ventilation system is turned on.

WARNING: Gasoline vapors can explode. Before starting engine, operate blower for four minutes and check (using your nose) engine compartment for gasoline vapors. 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.

Powerboats are built to ventilate the engine when underway. As the boat moves along, an air intake scoops up fresh air and forces it down the air duct into the engine compartment. The exhaust sucks out the explosive fumes from the lowest part of the engine and fuel compartments.

Mufflers and Noise Level Limits

Vessel operators may not hear sound signals or voices if the engine is not adequately muffled.

• All vessel engines must be equipped with an efficient muffler, underwater exhaust, or other effective muffling device that prevents excessive or unusual noise.
• A vessel operating on Arizona’s public waters must not exceed any of the following noise levels.
  • A noise level of 86 dB(A) when the sound level is measured at 50 feet or more from the vessel
  • For an engine manufactured before January 1, 1993, a noise level of 90 dB(A) when the stationary sound level test (SAEJ2005) is performed
  • For an engine manufactured on or after January 1, 1993, a noise level of 88 dB(A) when the stationary sound level test (SAEJ2005) is performed
  • A noise level of 75 dB(A) when the shoreline sound level test (SAEJ1970) is performed

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.