All vessels are required to have a Type B fire extinguisher on board if one or more of the following conditions exist:
- Inboard engine
- Closed compartments where portable fuel tanks may be stored
- Double-bottoms not sealed to the hull or not completely filled with flotation material
- Closed living spaces
- Closed storage compartments in which flammable or combustible materials may be stored
- Permanently installed fuel tanks
Approved types of fire extinguishers are identified by the following marking on the label—“Marine Type USCG Approved”—followed by the size and type symbols and the approval number.