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Analyzing Onboard Fire Claims

Onboard fires happen more than you'd think. Here's what digging into the GEICO | BoatUS Marine Insurance claim files teaches us about preventing them.

Causes of boat fires charts

Fire ranked No. 5 among the causes of loss for GEICO | BoatUS Marine Insurance between 2015 and 2019. The majority of these fires started in a few very specific places aboard, with many of them originating in the engine compartment where fuel and an ignition source have a high likelihood of coming together. Maintaining your boat well, particularly with respect to the electrical and fuel systems, is the best way to prevent fires aboard. However, there are five specific areas that lead to most of the fires we see in our claim files. If every boater paid attention to these, we could prevent a third or more of all fires aboard boats.

Battery cable connector

While loose battery connections, chafed battery cables, and aged battery switches can all cause fires aboard, the most common cause of battery-related fires is operator error: reversing the battery cables or connecting them in series when they should have been in parallel or vice versa. If you're disconnecting your batteries for any reason, photograph the configuration using your phone, label the battery cables, and mark the positive lug with red fingernail polish to avoid a shocking experience when you reconnect them.

Exhaust hose

Any interruption of cooling water can lead to overheating and then to a fire. In this case, a blockage of the raw-water intake caused the overheating. Other exhaust fires are caused by impeller failures due to age or sediment in the water. If your engine overheats, check the engine compartment before getting underway again. Change your impeller every other year, after a grounding, or when operating in particularly dirty waters.

Marine fire claim

More than a quarter of the time, our insureds' boats burn when something else goes up in flames — the marina, the storage facility, the house, the garage, the barn, the neighbor's house. In more than 70% of those cases, it's the marina that burns. A high percentage of those fires start on someone else's boat. That means that every boat owner has a responsibility to prevent fires on board, not just to keep his or her boat safe, but also to keep the people, boats, and property around it safe.

Shorepower inlet

Bringing air conditioning, microwaves, electric heaters, and other AC electrical appliances aboard makes life on the dock more comfortable and convenient but also greatly increases the risk of fire. Most AC electrical fires start somewhere between the marina pedestal and the shore power inlet on the boat. BoatUS has long recommended using only marine-grade power cords with proper adapters and replacing them at the first sign of wear on the cord or pitting on the blades of the plug. But an analysis of our fire claims has identified another high-risk area on boats more than 10 years old: the back of the shore power inlet where the ship's wiring connects to the terminals. Replacing the shore power inlet on older boats if it is original, or at least pulling it out and inspecting the connections, could well save your boat.

Voltage regulator

On older outboards, the voltage regulator is by far the most common cause of fires. The failure rate increases with age after 10 years. So if your outboard is at least 15 years old, replacing the regulator may well keep you from having a bad day on the water.

Wiring harness

Wiring harnesses and starters cause a disproportionate number of fires on boats that are more than 25 years old. If you have a vintage boat and those parts are original, consider replacing them. Most of these older boats had relatively simple wiring harnesses, so if the manufacturer is no longer in business or the part is no longer available, a good electrical technician can put one together for you.

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Mark Corke

Contributing Editor, BoatUS Magazine

A marine surveyor and holder of RYA Yachtmaster Ocean certification, BoatUS Magazine contributing editor Mark Corke is one of our DIY gurus, creating easy-to-follow how-to articles and videos. Mark has built five boats himself (both power and sail), has been an experienced editor at several top boating magazines (including former associate editor of BoatUS Magazine), worked for the BBC, written four DIY books, skippered two round-the-world yachts, and holds the Guinness World Record for the fastest there-and-back crossing of the English Channel — in a kayak! He and his wife have a Grand Banks 32.