All about marine fire extinguishers

The U.S. Coast Guard requires marine fire extinguishers on all recreational boats where a fire hazard could be expected from the engines or fuel system. So, how do you know which type and how many fire extinguishers to carry? We answer all your questions.

Does my boat need a marine fire extinguisher?

The Coast Guard requires fire extinguishers on boats with

inboard engines and outboard boats with closed compartments for storing permanent or portable tanks,
permanently installed fuel tanks, and
closed compartments or living spaces.

What type of marine fire extinguisher should I buy?

Coast Guard-approved extinguishers for boats should be

hand-portable,
have either B-I or B-II classification,
and must be provided with a mounting bracket.

Purchase only marine fire extinguishers with Coast Guard approval that has been certified by an independent testing agency, such as Underwriters Laboratories. Next, look for the section of the label that states “Marine Type USCG, Type A, Size II; Type B; C Size I.” (It should also contain a USCG approval number.) Make sure Type B is indicated on the label.

However, extinguisher markings can be confusing. For example, one extinguisher can be approved for several different types of fires (A, B, or C). In that case, it’s important to know that an extinguisher marked “Type A, Size II; Type B; C, Size I” counts as a required Type B-I extinguisher.

Hand-portable extinguishers come in two different sizes. Moreover, this size indicates the amount of chemical an extinguisher contains:

Size I extinguishers must contain a minimum of 2 pounds of dry chemical.
Size II extinguishers contain at least 10 pounds of dry chemical.

How many marine fire extinguishers do I need?

The minimum number of portable extinguishers you’re required to carry depends on your boat’s length. However, if you have a U.S. Coast Guard-approved fixed fire extinguishing system installed in your boat’s engine compartment, you can reduce the required number of extinguishers using the chart below.

Minimum Number of Hand-Portable Fire Extinguishers Required

Vessel Length

< 26 feet

26 to < 40 feet

40 to 65 feet

No fixed system

1 B-I

2 B-I or 1 B-II

3 B-I or 1 B-II and 1 B-I

With fixed system

1 B-I

2 B-I or 1 B-II

Do I need a fixed extinguisher system?

Fixed systems for use in engine compartments and enclosed spaces can be automatically deployed. For this reason, they are invaluable in saving a boat from an engine fire.

If your boat has an inboard, inboard/outboard, or jet drive engine in an enclosed space, you should strongly consider installing a fixed fire extinguisher system.

By discharging into a closed engine compartment, fixed extinguisher systems avoid adding oxygen to the fire. It’s important to note that to prevent reigniting a fire after a fixed system has discharged, you should not enter the engine compartment immediately. Instead, wait until the compartment has cooled and been well ventilated.

Where do I mount my handheld marine fire extinguishers?

Mount fire extinguishers near fire hazards but not so close that you can’t reach them safely during a fire. Don’t mount them where they will project into busy passageways. Most importantly, consider mounting extinguishers near the engine compartment, at steering stations, inside galleys, and in passenger cockpits. And if you sleep onboard, keep one near your bunk.

How do I maintain a marine fire extinguisher?

Check extinguisher gauges monthly.
Make sure they’re at full pressure. Gauges can sometimes be unreliable.
Recharge size I and II rechargeable extinguishers at a qualified service center. Rechargeable extinguishers have metal, not plastic, heads. Get them inspected annually.
Check for corrosion or mechanical damage to the extinguisher case.
Check and clean the discharge nozzle. Insects love to build nests inside.
Slowly rock dry chemical extinguishers from an upright to an upside-down position several times. If you feel a thud, the chemical has stuck together. This means the extinguisher won’t function properly.
Replace and dispose of old extinguishers properly.

How do I use a marine fire extinguisher?

To control a fire, you want to extinguish it while it’s still small. In addition, you can increase your chance of success by carrying more than the minimum required number of extinguishers onboard.

To put out a fire, hold the extinguisher upright and use the PASS technique.

What else do I need to know?

Never test a marine fire extinguisher by partially discharging it. It could leak and become unusable. Always make sure to recharge or replace partially discharged extinguishers. And lastly, purchase only Coast Guard-approved extinguishers designed for marine use.

For more information about marine fire extinguishers, download a Boater’s Guide to the Federal Requirements.