All vessels are required to have a Type B USCG–approved fire extinguisher on board if one or more of the following conditions exist:
- Inboard engine
- Double-bottoms that are not sealed to the hull or that are not filled completely with flotation materials
- Closed living spaces
- Closed compartments where portable fuel tanks may be stored or 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 type and size symbols and the approval number.