Marine Fire Extinguishers
Do you have a proper marine fire extinguisher aboard your boat? You may only have seconds to put out a fire. And fire on board is serious stuff; there’s nowhere to go but overboard, and that’s a whole other problem. Here’s what to look for in marine fire extinguishers.

Fire Types and Extinguishing Agents
Class A fires include ordinary combustibles such as wood, paper, cloth, trash, etc. The best extinguishing agents for an A fire are water or chemical foam.

Class B fires involve flammable or combustible liquids. The best extinguishing agents for a B fire are carbon dioxide, dry chemical or aqueous film-forming foam (AFFF).

Class C fires involve electrical equipment. The preferred extinguishing agent is carbon dioxide. Dry chemical can be used.

Class D fires involve combustible metals, like magnesium. The best extinguishing agent is a dry powder suitable for the metal involved. This class of fire is not likely to occur on a fishing vessel.

What You Need
Fire extinguishers are classified by a letter and a Roman numeral. The letter indicates the type of fire (A, B, C or D) it is designed to extinguish, and the numeral (I, II, III, IV or V) indicates the size of the extinguisher. The higher the numeral is, the larger the extinguisher will be. Sizes I and II are portable by hand, and sizes III, IV and V are semiportable.

Regardless, all extinguishers used on boats must be U.S. Coast Guard-approved and rated for marine use. Boats that are less than 26 feet long must have at least one B-I extinguisher in place; boats 26 to 40 feet must have two of these. Boats larger than 40 feet but less than 65 feet must have three.

Easy as 1-2-3
Boating recommends you carry at least one more than the required extinguisher and at least one ABC-rated extinguisher.

Check out this video for tips on making sure your fire extinguishers are fit for service.