Fire extinguishers are categorized based on the type of fires they put out and the type of chemicals they use to do so. A B-I fire extinguisher is designed to put out fires that boil and that are started from all flammable liquids. Usually, boats carry B-I fire extinguishers, as the fires that start on boats are usually from flammable sources and are boiling fires. This is also will prevent the need for people to jump overboard.