Transcription
An electric boat explodes while charging. Debris flying over 40 feet across the canal. And yes, even lithium iron phosphate batteries can go into thermal runaway. You found stashed. I'm Pat, firefighter, mechanical engineer, and battery guy.
On August 5th, 2025, an electric Day narrow boat at the Gaytown Marina, it exploded and caught fire while it was charging. This wasn't a minor incident. The blast was big enough to warp the boat steel structure and blow debris across the water to the other side of the marina. The deflagration hazard, that's one of the main challenges with lithium iron phosphate batteries. And by deflagration, I mean explosion. But I'll come back to that.
Here's what I found about the boat. The vessel is part of the ABC Leisure Group's higher fleet. It's a 36 ft electric day higher narrow boat powered by a 10 kW electric motor. Just be aware the footage I'm showing here, it's from a similar boat from their fleet, but they're designed to be for a leisurely day out, like a trip, hanging out with your family, maybe a a small group of friends, having a picnic, definitely having some tea over there, and it just it's designed to putter along this canal system for the day.
In the past, these boats would have run off diesel engines. However, in this case, the motor run off of 48vt lithium ion batteries. There were lithium iron phosphate batteries, LFP, however you want to say it. But there were two battery banks, each 20 kwatt hours. One was set up for the actual motor itself, for the propulsion of the boat. The other was set up for the cabin for the house, for things like the refrigerator, the electric stove, the teac kettle, some outlets on board. It's really similar to what you'd see on a lot of RV or off-grid setups.
This boat had no diesel, propane, or gas systems. Even the stove inside the cabin was completely electric, making for a fully zero emission setup. At least emissions, you know, at the boat itself. The motor sat underneath the stern deck with the batteries. Realistically, this is a terrible place for batteries. That's because typically that compartment, it gets a fair amount of moisture inside. Water will come in both through the rudder post and the prop shaft, and the village is constantly removing water. So, yeah, the battery is sitting in a fairly moist environment. Not a good idea.
It's also an enclosed space, limited ventilation, fine for normal operation, but if the battery goes into thermal runaway, that confined volume can fill up quickly with smoke. I use the term smoke loosely because that smoke is actually an extremely flammable vapor.
Let's talk about two different battery chemistries. Nickel, manganese cobalt, or simply NMC. Those batteries tend to burn violently when they fail. And here's the thing, it's not technically the battery itself that's burning. Yes, they get extremely hot, but when NMC batteries go into thermal runaway, it releases gases made up of roughly 25% hydrogen, 35% carbon monoxide, both flammable, and then 35% carbon dioxide, and a mix of other hydrocarbons. The chemical reaction itself, again, it's so hot that the carbon monoxide and the hydrogen, they ignite almost immediately and they burn violently. Believe it or not, I'd rather see fire because the alternative is not good.
That's because lithium iron phosphate or LFP batteries, those failures often cause explosions. LFP batteries typically off gas a flammable cocktail that's about 55% hydrogen and 10% carbon monoxide. Since thermal runaway in LFP cells isn't quite as hot, those gases can build up until a deflagration occurs. You know, a big boom. Since the boat used LFP batteries, that's likely what happened here.
On the morning of the 5th, the boat was on charge. Witnesses reported a large bang followed by flames engulfing the cabin. Glass shattered, parts of the hatch blew off, and the fire spread rapidly. While the location of the batteries was in the stern directly under this area here, it had a path to off gas and that allowed the rest of the structure to get consumed pretty quickly.
So, how did that gas get into the vessel? How did it get into the cabin? And what ignited the mixture? If you look at where all the electronics are located, you'll see large openings through the bulkhead for the wiring. A single battery failure would have off-gassed enough to make the atmosphere inside that battery compartment or the engine compartment, motor compartment, whatever you want to call it. It would have been an extremely rich mixture of flammable vapor. But inside the cabin, that larger volume would have allowed the gases to mix into a perfect explosive concentration. It would only have taken a single spark from something as simple as a fridge to set that whole thing off.
Should something like this happen? No. The batteries themselves each have an internal battery management system. It balances the cells and the charging system should work with that battery management system to ensure there's no issues. But unfortunately, electronics can fail. And even though each battery should be perfectly sealed, we know nothing is perfect and being in a moist environment is a possible failure mode.
If you look at the aftermath, the damage tells a story. The cabin structure is ballooned outward as the blast tried to push the boat apart from the inside. Several panels are missing entirely, either blown clear by the explosion or destroyed in the fire. And some of those panels made it to the other side of the marina. This isn't the kind of damage you see from a slow smoldering fire. It's the result of a rapid pressure buildup and a violent release. The hull itself was still afloat, but the inside cabin was gutted.
When Northampton Shire Fire Rescue arrived, they faced a problem similar for all lithium-ion battery fighters. You don't just put them out. Water was applied, but not to extinguish the burning cells. And they really didn't have access to those batteries. Anyway, firefighters were cooling surrounding buildings like the locker containing fuel and guarding tools and controlling embers that could ignite nearby boats. Apparently, the decision was made to sink that boat and suppress the fire. My guess is they flooded the motor compartment and only sunk the back of that boat. Even then, it wasn't the end of it. After the water was pumped out, the batteries reignited, which isn't really that much of a surprise.
Fires on the water are always dangerous, but lithium-ion batteries are especially aggressive in closed spaces. Even with lithium iron phosphate chemistry, which again, it is typically safer, but it can still fail, produce intense heat, flammable vapors, and explosions. They need to be located in compartments that are well ventilated. The placement of large capacity lithium-ion batteries inside a passenger compartment or adjacent to that cabin where you've got the risk that it can off gas into the cabin. That's a problem when things go wrong and it becomes a life safety hazard if people are in the boat.
I'm seeing this type of hazard more and more, especially in off-grid setups in motor homes and RVs. Look, I get it. I use LFP batteries in my own motor home, but I respect the hazard and I understand the hazard. I've seen a lot of installs where the batteries are mounted underneath the bed. And while this example is just a single battery, I've seen some setups that are upwards of 10 kilowatt hours. That's incredible. What happens if there's a failure? Are you even going to be able to get out in time? The carbon monoxide production alone could incapacitate you before you even realize there's a failure. It's all about common sense. And people selling these batteries as 100% safe, it's going to get somebody killed.