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, U.S. Coast Guard–approved fire extinguisher(s) on board if one or more of the following conditions exist:

• Inboard engine
• Vessel length of 26 feet or longer
• Closed compartments where portable fuel tanks may be stored
• Double-bottoms which are not sealed to the hull or which are not completely filled with flotation material
• Enclosed living spaces
• Closed storage compartments in which flammable or combustible materials may be stored
• Permanently installed fuel tanks

Approved types of fire extinguishers are identified by the following marking on the label—“Marine Type USCG Approved”—followed by the size and type 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 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(s) and check for any damage.

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 Level Limits

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

• Every vessel with an engine must be equipped with a muffler system in good working order and in constant operation to prevent excessive noise.
• A vessel must not exceed the following noise levels.
  • Measured using a stationary test: For engines manufactured before January 1, 1994, the maximum noise level is 90 decibels; for engines manufactured on or after January 1, 1994, the maximum is 88 decibels.
  • Measured from the shoreline: For all vessels, the maximum operational noise level is 75 decibels.
• You may not remove or modify a muffler or muffling system if the result is increased noise level.
• The use of a muffler cutout or a muffler bypass system is prohibited except while engaged in organized racing events in an area designated for that purpose.

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.