A building fire gets a fire department in minutes. A vessel fire offshore, in the Gulf Stream, or at a remote anchorage gets whatever is aboard. The crew and the boat’s own systems have to detect the fire, knock it down, and keep it from reaching fuel tanks or spreading through the accommodations before anyone else can help.
Modern yachts make that harder. They carry large fuel loads, lithium battery banks, generators, high-output inverters, galleys, and accommodations finished in wood, fabric, and foam. Commercial vessels add passengers who do not know the boat, long operating hours, and machinery running at sustained load.
Protection works in layers: automatic fixed systems in machinery spaces, smoke and heat detection in the accommodations and engine room, and portable extinguishers of the right type and rating where the crew can reach them. Coast Guard rules set minimum carriage requirements by vessel size and type, and ABYC A-4 and NFPA 302 describe how equipment should be selected and installed.