What Type of Fire Extinguisher Do You Need on a Boat? (Explained!)

The Coast Guard states that all boats should have no less than one B-1 marine fire extinguisher at the ready at all times. This is not a law but highly recommended.

Here are the requirements for having a fire extinguisher that every boatman must consider:

  • Permanently installed fuel tanks
  • A closed compartment containing a portable fuel tank
  • Unsealed double bottom at the hull that does not entirely store flotation materials
  • Enclosed living spaces on the boat
  • An inboard engine

The size of your vessel will determine the number of extinguishers you must keep on board. The length also indicates what type of fire extinguisher you need.

  • Less than 26 feet: 1 B1 extinguisher
  • Between 26 and 40 feet: two B1 or a B2
  • Between 40 and 65 feet: three B1 or two B2

If you have a vessel longer than 65 feet, you should check applicable federal regulations for the required type of fire extinguisher.

What Type of Fire Extinguisher Do You Need on a Boat?

Most boat fire safety needs are manageable with a tri-class dry chemical extinguisher, which is ideal for boats with electronics or engine compartments that lack a fixed well. 

A tri-class extinguisher is a device most likely to handle all types of fire. You can get an A, B, or C solution. Purchasing an ABC device greatly improves your chances of safely stopping a variety of fire types.

Know Your Fire Extinguisher

Take time to review directions on the extinguisher closely. Many consumers fail to do that. While the extinguisher looks easy to use, most people tend to find they don’t know what to do — or in the heat of the moment, forget what to do. 

Always examine the device for performance. If there are friends or family of age who regularly ride with you, everyone should know how to retrieve, activate, and use a fire extinguisher. 

Make a monthly inspection of the extinguisher part of standard boating maintenance. Here are some tips:

  • Make sure the fire extinguisher is fully charged. Check the gauge.
  • You don’t want any broken seals.
  • Inspect the hose for cracks or leaks. 
  • If you have a dry chemical extinguisher, check the weight of the device. It should meet the minimum weight as noted on the label.

If any of these criteria fall short in your inspection, replace that extinguisher immediately.

How the Fire Extinguisher Works

It’s a good idea to know how fire extinguishers function.

Once a fire starts, it burns and generates heat. When water hits the flame, the liquid boils and dissipates. The resulting steam floats away, taking the heat with it and stopping oxygen from feeding the fire.

The typical fire extinguisher also works to separate the fuel from oxygen. Since the fire needs oxygen to keep going, you use the extinguisher to coat the fuel with a compound that keeps oxygen away. 

However, keep in mind that various types of fires exist, and you must address each one differently.

Types of Boat Fires and the Extinguisher to Combat Them

There are three primary classifications for fuel sources. They are liquid, solid, and electrical fires. Each category burns differently and shows what type of fire extinguisher you need on a boat. 

Class A: Combustible Solids

Class A is a solid combustible fire fueled by paper, textiles, plastics, or wood. Water or a Class A device – that usually contains monoammonium phosphate – will put out this fire. 

Class B: Flammable Liquids

Class B fires come from a source of flammable liquid, such as grease and gasoline. You can’t use water because it will only intensify and spread the flame. A Class B fire extinguisher uses a dry chemical, like powder or foam, to remove oxygen and smother the flame.

Class C: Electrical Hazards

Class C fires result from an electrical mishap. Again, water is useless in this situation because it conducts electricity and can result in electrocution. Class C fire extinguishers may contain potassium chloride, potassium bicarbonate, or monoammonium phosphate to put out electrical fires.

The primary reason Class B is the suggested protectant on boats is that gasoline fires are the most common type on these vessels. 

There are two other types of extinguishers. Class D is for more industrial conditions where you’d have flammable compounds, such as titanium or magnesium. 

Class K is a solution engineered specifically for the kitchen. The design is for tackling fires when there are mishaps with vegetable fats, cooking oils, animal fats, or grease. Fires ground in these elements break out fast and spread quickly. 

While you can have a Class K on your boat, it doesn’t make sense since Class B can handle the same situations.

How and Where to Store Your Fire Extinguisher

The recommendations state that you always store your fire extinguisher in an upright position. When you set extinguishers up horizontally, you increase the possibility of compacting the contents at the tank’s base. 

That condition is a threat. It means you could grab the extinguisher at a critical moment only to find the imbalance results in a propellant discharge without the extinguishing agent.

Depending on the size of your boat, keep extinguishers in rooms most likely to see a fire. That can include the cabin, hull, kitchen (or grill areas), or bilge.

Another good idea is to have a fire extinguisher in high traffic or high-risk areas. Keep tri-class or dry chemical extinguishers near exits in those areas.

When placing extinguishers, take into account:

  • Where the gas tank is located
  • Where the kitchen and/or grill are and if those areas get cleaned regularly
  • Where boaters congregate
  • How often you clear trash and debris
  • Where you’re storing gasoline and other flammable liquids

You want to know the areas that have a high probability of a fire. Make sure the kitchen is clear of oil spills, trash, and debris.

The answers to these questions not only tell you where you need to put devices but should also provide insight into how many fire extinguishers you need. In the case of a fire, you wouldn’t want to cross a great distance to get an extinguisher. Fires grow fast, and you don’t want to find out just how fast!

Using the Extinguisher

The last thing you want to do is figure out how to work an extinguisher when you need it most, which is why regular inspection and knowing that the device is operational matters. 

Most importantly, stay calm when you attack a fire. Many fires have surged while anxious boaters fumbled to get their fire extinguisher working.

  • Pull out the pin.
  • Aim the nozzle or hose from the safest distance. (That should be instructions in the operational guide.)
  • Squeeze the lever to release the contents.
  • Thoroughly cover the fire by sweeping the hose or nozzle across the inflamed area.

Pull. Aim. Squeeze. Sweep. That’s P.A.S.S.


Knowing what type of fire extinguisher you need on a boat is just the first step in keeping you safe. Ensure you know how to use it properly, regularly clean the vessel to avoid hazards, and engage in safety precautions for storage to improve the chances of safe water adventures. 

For further details on understanding different fire extinguishers, check out these tests and reviews performed by the National Fire Protection Association