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.

• The length of the vessel is 26 feet or more.
• The vessel has closed compartments.
• The vessel is powered by an inboard or stern drive engine.
• The vessel is carrying passengers for hire.

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.

All powerboats (except outboards) that are fueled with gasoline must have one of the following.

• A backfire flame arrestor on each carburetor. Flame arrestors must be approved by the USCG or comply with SAE J-1928 or UL 1111 standards and be marked accordingly. Periodically clean the flame arrestor and check for any damage.
• An arrangement of the carburetor or engine air induction system that safely disperses any flames from a backfire to the atmosphere outside the vessel.

Paper or automotive filters are not USCG–approved and are dangerous to use.

Backfire Flame Arrestor A U.S. Coast Guard–approved backfire flame arrestor should be on each carburetor of inboard or stern drive engines fueled with gasoline.

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.

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 Limits

All vessel engines must be equipped with an effective, permanently installed muffling system that cannot be bypassed. Vessel operators may not hear sound signals or voices if the engine is not adequately muffled.

• Vessels built before January 1, 1995, must not exceed 90 dB(A) using the stationary test.
• Vessels built on or after January 1, 1995, must not exceed 88 dB(A) using the stationary test.
• While operating on lakes and rivers wider than 500 feet, it is unlawful to exceed 75 dB(A) as measured from shore.
• Contact your local sheriff’s department for a free screening of your vessel’s noise.

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.