Fire on a boat is one of the skipper's greatest fears and one of the major causes of damage to boats. It is advisable that all boats carry marine designated fire extinguishers. For protection, all motorboats must carry readily accessible fire extinguishers that are U.S. Coast Guard approved. Fire extinguishers are classified by letters and numbers according to the type and size of fire they can put out. The letter indicates the type of fire: "A" for combustible solids like wood; "B" for flammable liquids; "C" for electrical fires; and "D" for combustible metals like magnesium.
Fire extinguishers are not required on outboard motorboats less than 26 feet in length, which do not carry passengers for hire, are of open construction and have no permanent gas tanks installed. ( But it's a darn good idea to have one anyway. )
Which Extinguisher (Type of Fire)
1. Carbon Dioxide -- C02 (A.B,C)
2. Halon/Freon (A,B,C)
3. Dry Chemical (B,C)
4. Foam (B)
5. Water (A)
Fires involving burning wood and paper (Class A) can be put out with water, but
do not use water on gasoline, oil, or electrical fires. Water will cause a gasoline or oil fire to spread and will further damage electrical equipment. Most boat fires consist of burning flammable liquids such as oil or gasoline (Class B).
Some boat fires are caused by faulty electrical wiring (Class C). The current overloads the wire, gets it hot, and sets the insulation on fire. An extinguisher must be able to put out this fire without giving the user a shock. Use dry chemical, C02, or Halon/Freon. The number indicates the relative size of the extinguisher. A B-II extinguisher has four to five times the amount of extinguishing agent than a B-I.
Check frequently to be sure that fire extinguishers are properly stored and undamaged. Replace cracked or broken hoses. Keep nozzles free of obstructions. Check pressure gauges for proper pressure. Make sure that locking pins and sealing wires are in place.
Never try an extinguisher to see if it works properly. The valve may not reseal and a gradual discharge of the extinguishing agent results. After using an extinguisher, have it recharged before using it again.