All vessels are required to have a Type B fire extinguisher on board if one or more of the following conditions exist:
- Inboard engines
- Closed compartments under seats where portable fuel tanks may be stored
- Double bottoms that are not sealed to the hull or not completely filled with flotation materials
- Closed living spaces
- Closed storage compartments in which flammable or combustible materials may be stored
- Permanently installed fuel tanks (any tanks 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.