Firefighters Suspected Her Lithium Batteries. Now, There's a Big Insurance Investigation
$5 Million Power Cat Burns, Sinks at Longboat Key
Update 8:28 p.m.: An alert reader has identified the batteries in the sistership photo below (or possibly the vessel in question herself). He said they were Mastervolt Lithium Iron Phosphate (LiFePO4) batteries. The question remains, however, whether Steady AF was similarly equipped.
The yacht had ignited at a marina on Longboat Key in Florida, but it was her owner in Ontario, Canada, who actually noticed the fire first. By dawn on Tuesday, August 6, the Aquila 70 Luxury—flagship of the MarineMax powercat fleet—lay wrecked with her starboard hull underwater.
The name of the vessel is Steady AF,1 and she cost about $5 million. Now, she is the subject of an insurance investigation after Longboat Key firefighters surmised her lithium-ion battery bank may have been the cause of the fire, although no official determination has been made.
Steady AF will be towed from the Florida’s West Coast to its East Coast, where there are shipyards that can haul a vessel with a 27-foot beam. The investigator is Bruce Kerns of Kerns Fire Consultants, Apollo Beach, Florida. Kerns’ website notes that he has 35 years of forensic experience. (He also happens to be a sailor.)
The owner of the boat is Rob Tyler, 62, who gave a town in Ontario, Canada, as an address. That’s where he was when he noticed smoke.
He had been watching the boats cameras for a couple days due to of Tropical Storm Debby. A Longboat Key fire official wrote in his report. “At 1945hrs on 8/5/2024 he noticed what appeared to be smoke coming from the rear of the vessel. He then called his dockhand at (2001hrs) and got no answer. He called several others with no answer. He then called the Moorings emergency number. Dockhand James Staples arrived and noticed smoke at the rear of the vessel and called 911.”
According to the report, Tyler then booked a flight back to Florida. When he arrived at the scene at 4 p.m. the next day, fire officials reported that he appeared shocked.
Tyler told Longboat Cay fire officials that he had been monitoring the boat’s electrical system over the weekend—the fire was on Monday—and noticed that the voltages were fluctuating. He asked a marina employee to have a look, Patrick Sherman.
Sherman, according to the fire department report, checked and toggled the shorepower breaker, and checked the breakers on board the boat, too. One was tripped, and he reset it. That was Saturday.
Tyler, according to the report, had Sherman return on Sunday. He touched the batteries, and they were not hot. Someone else checked the boat on Monday, while Tyler watched over the live feed from his vessel’s camera system.
When firefighters arrived at 8:40 p.m. on Monday they saw smoke around the stern. Steady AF was tied to a facedock, with the adjacent slip occupied by another vessel. Engine access was possible through aft deck hatches. Firefighters found flames when they opened the starboard hatch. They soaked the engine space “with no effect on the fire.”
The on-scene commander called for fire-suppressing foam as the flames spread into the saloon. According to the report, the foam had little effect as the fire spread upward into the flybridge. The boat began listing to starboard.
At this point, fire officials surmised that they were dealing with a lithium-ion battery fire undergoing thermal runaway. That is, the internal heat inside battery cells had risen so high that the fire is nigh unstoppable. “Command called for transition to defensive attack with three fireboats from various angles and handlines from the dock,” fire officials later wrote, describing a change in tactics.
“You’re fighting a losing battle. You basically have to let it do its thing,” Assistant Chief Jentzen Barton told a local media outlet.
Now, the object would be to prevent the fire from spreading while waiting for it to burn itself out, which it did at around 6 a.m. on Tuesday, leaving Steady AF half sunk and her batteries submerged.
Lithium-Ion technology has been widely adopted by both manufacturers and individual boaters, and the American Boat & Yacht Council concluded two years ago that Lithium Iron Phosphate (LiFePO4) technology was safe after the standards-setting agency conducted a series of tests.
As far as Steady AF, there is no indication in the reports about which lithium technology was installed in the boat, but, according to a reader, the batteries pictured in the publicity shot above are Mastervolt LiFePO4.
Earlier in 2022, ABYC had adopted its long awaited standard for lithium-ion battery installations. It’s instructions were bareboned, stressing the need for quality batteries and monitoring systems and strict adherence to manufacturer instructions. ABYC is adding to the standard as more data comes.
Jim Healy is an East Coast cruiser with a Monk 36 named Sanctuary. Healy, is a former member of the ABYC technical committee that is preparing to rewrite ABYC lithium battery standard for publication in July 2025. Healy and marine surveyors with whom Loose Cannon has spoken, stress that despite their growing acceptance, lithium-battery technology is still not fully understood.
Writing for the online forum of the Marine Trawler Owners Association, Healy recently argued that marine lithium-ion battery installations are like one big, collective beta test:
A lot has been learned and a lot has changed in the last three years in the area of lithium bateries on boats, and a lot is still coming to light as write these lines. Yes, there will be a new standard in 2025 for lithium batteries. It will have extensive changes over the current standard. But, do not expect it to be complete. We are in a period of beta testing a new and emerging technology, and we still don't have all the answers we'd like to have.
Most skepticism of lithium-ion on boats is directed at individual owners who convert to lithium batteries on a “drop-in” basis, not so much boatbuilders. The MarineMax Aquila 70 is professionally outfitted to U.S. and international standards. Aquila is a brand created in 2013 by MarineMax with Chinese company Sino Eagle Group with its factory in Hangzhou City, China. The Aquila 70 debuted in 2021.
Usually, after an article like this is published, lithium-ion adopters will comment about the distinction between the high-energy lithium-ion batteries found in phones and other portable devices, and the more stable LiFePO4 batteries for boats. And which, yes, do have a much better safety record.
Meanwhile, investigator Bruce Kerns will be looking for evidence of manufacturing or installation defects that will help Steady AF’s insurer to recover whatever monies it pays out from parties deemed to be at fault. Kerns did not respond to a message with questions.
Steady (As Fuck). Likely the name refers to the lateral stability of catamaran designs, combined with a bulbous bows (albeit pointy ones), which might reduce pitching motion.
While it's technically not an ABYC violation, because they are after the fuses, the row of exposed bus bars above the battery bank, between the fuses and switches, represents poor electrical attention to detail. When I see this sort of practice on a vessel, it immediately makes me wonder what other sloppiness exists, and I almost always find it.
I always cite exposed DC positive terminals as serious hazards, especially high current, again even though insulation is technically not required by ABYC E-11 (I sit on the ABYC electrical standards committee, which includes lithium batteries, these standards are imperfect, and always works in progress, but that's another post).
Having inspected and helped design many large LFP (and conventional) battery banks and charging systems, I'm fairly well convinced that LFP batteries from respected manufacturers like MV, Victron, Lithionics and others aren't catching fire. However, because these batteries can accept sustained very high rates of charge, and discharge, they stress electrical systems in ways they were not previously stressed with AGM batteries. This means, a stainless steel washer incorrectly located under a fuse or ring terminal, on an LFP system, can lead to a fire rather than just turning purple. This places a very high responsibility on installers to avoid even the smallest errors, like inserting a stainless washer in the current path.
In this case it appears the system was at rest per se, so this scenario should not have been possible, however, such a scenario could have previously led to an overheated connection, which later arced, which in turn caused this fire.
In addition to other locations, smoke detection in the vicinity of chargers and battery banks is mandatory in my book, and for vessels of this value, smoke alarms that report remotely to an app or text, are highly recommended. If this vessel were so equipped, the fire may have been detected far sooner than the owner seeing smoke on a camera, and the source possibly eliminated. The fluctuating voltage was a clue, but there's no substitute for smoke detection. Presumably the owner's insurer didn't have a lithium exclusion. Hopefully the forensic fire investigator's report is made public, but that is unfortunately rare.
It's likely the fire had nothing to do with the batteries, aside from them possibly feeding power into burning conductors, that could been ignited by something else. I don't think the LFP cells in the MVLi batteries can even burn all that hot. However, in a forced overcharge, it's likely they can burn hot enough to melt and burn the plastic cases, which can create a lot of smoke which could appear like a more significant fire than is actually occurring.
A key question is which on-board breaker was it that tripped and was reset.
And the fluctuating voltage is interesting, suggesting that they should look at AC to DC charging, and possibly whatever large AC or DC loads may have been running at the time...which may have been powered by the tripped breaker; only to be reset...rather than carefully checking whatever device/load that was. It's possible they may have been able to discover the fire/heat source, before they gave it another chance to go up in smoke....