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 that are not sealed to the hull or that are 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 (any tank where the removal of the tank is hampered by the installation of tie-down straps or clamps)
Approved types of fire extinguishers are identified by the following marking on the label—“Marine Type USCG Approved”—followed by the type and size symbols and the approval number.