Explosions that happen at the ramp are often caused by fumes built up in the bilge/engine compartment. That’s why you run your blower for a few minutes before starting the boat. For a boat that’s out on the water already, the bilge pumps have been operating all along, although they can fail.
One man who was interviewed on Good Morning America this morning had lost five family members, his parents and his three sisters. I cannot imagine his heartbreak right now.
How horrible.
I am no nautical engineer, but for a boat of this size, two exits, widely separated, would seem at least adequate. Having only one might be dangerous, but knowing there were two makes me feel like the design didn’t contribute to the problem.
The most recent news report I saw this morning says that the escape hatch didn’t lead to the rear or outside of the boat, but to the deck above, in the dining area next to the galley.
If the purpose of the fan is to evacuate potentially explosive gas then yes. If not it assumes a sealed fan motor or a unit that blows into the bilge versus pulling the air from the bilge. Otherwise you risk igniting fumes.
If this is a propane issue then no amount of exits might have helped. Propane won’t explode in the classic sense. It will expand out and burn up all the oxygen around it. video.. This was a small leak and you can see it rapidly burn along the floor line where the heavier than air gas leaked and then ignited off the pilot light of the water heater. If there is no ignition source close to the ground then the gas builds up until it finds an ignition source. It then pushes itself outward from that source as it burns.
The boat is sunk in 64 feet of water.
One interesting fact came out today. One of the people who perished was the cook who was hired for the charter. He’d worked for them many times before. He would typically start preparing breakfast at around 4am which was when the fire started. The galley fire hypothesis makes more sense now.
I hadn’t heard that yet, but today was crazy at work and I haven’t kept up with the news. It completely makes sense though given what we know. If the galley’s on fire then neither of the exits are workable.
I did walk down to the harbor at lunch to look at the growing memorial. Couple thoughts: that’s more news trucks than I think I’ve ever seen in one place, and seeing Vision and Truth with the empty berth between then was a sobering moment to say the least.
The distress call went out at 3:15 a.m., so that timeline doesn’t work. Also the owner of the boat was interviewed and stated the kitchen was all electric, so not a gas leak. Could be an electrical fire or exploded battery; divers use a lot of rechargeable lithium ion batteries and typically leave them charging overnight, often on a table in the galley, where the fire appears to have started.
Slow burns like the one in your video happen when there is inadequate opportunity for the fuel to mix with the air before ignition. the “small” leak in your video was large enough that a river of mostly homogenous propane was able to reach the burner; the progress of the flame front after that is limited by mixing of the propane and air. See figure M3-10 on page 17 of this PDF file: hydrogen, acetylene and ethylene burn pretty fast, but the alkanes (methane, ethane, propane, butane, etc.) are all in the same ballpark, and in fact propane actually has a flame speed slightly higher than natural gas, the latter of which is famous for occasionally blowing houses to bits. Bottom line, if a propane vapor cloud is given adequate time for air to diffuse into it, then you have a mixture that is capable of rapid combustion. Were this not true, it would not be possible for internal combustion engines to run at their usual range of speeds when using propane.
Here is a premixed propane-air explosion.
The video you linked to shows a more complex event, a boiling-liquid/expanding-vapor explosion (BLEVE). The sequence of events in your video is something like this:
- a tank containing pressurized liquid propane ruptures.
- the liquid, no longer under pressure, rapidly vaporizes and expands.
- the violently-expanding cloud of gaseous propane and atomized liquid propane (the white cloud in the video just before the fire happens) mixes with the surrounding air.
- the cloud reaches an ignition source, and a flame front propagates across the cloud.
A BLEVE like this is quite rare. Propane tanks contain safety valves that will vent propane vapor if the pressure exceeds a predetermined limit. This presents the risk of a fire from the expelled vapor, but reduces the risk of a violent tank rupture and subsequent massive explosion. You can still get the tank to rupture, but it typically takes a huge fire to get the tank so hot that the safety vent can’t release propane vapor fast enough to keep the pressure down below the rupture limit. The alternative is a structural flaw in the tank that allows it to spontaneously rupture.
The batteries divers might use would be pretty small; even diver propulsion units only have batteries the size of motorcycle batteries (~20 A-h). A charging problem might start a fire and spray some sparks, but it wouldn’t instantly incapacitate everyone in the sleeper cabin.
According to this article, “Authorities said Tuesday there was no indication of an explosion.” The only alternative to an explosion is a vigorous fire that spreads over a short-but-finite amount of time. But I’m puzzled as to how a fire could have spread so rapidly as to block both exits before any of the passengers could get out. 30+ people down there, and not one of them was a light sleeper or insomniac who could notice the growing fire before it blocked both exits?
That’s interesting… because the specs for the galley list an “Onboard built-in Bar-B-Que”.
A college friend on FB just posted a picture of one of the victims who he worked with in Antarctica. It’s an amazing small and fragile world.
A couple questions to consider would be:
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How well-lit was the berthing compartment at night?
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How aware were the occupants of an emergency exit?
Finding your way anywhere in the dark is difficult. Finding your way in the dark to an exit you don’t even know is there, possibly with a bunch of people trying to go the other way down a narrow passage, and maybe a bunch of backpacks, blankets, and pillows cluttering up the deck is something else.
I hope everyone died in their sleep. I fear they may have died in circumstances I cannot, or at least should not, seek to describe.
Fair points. Presumably one of the responsibilities of the crew when taking on a new set of passengers it to inform them of the location of things like fire extinguishers and emergency egress points. No doubt the coast guard and/or NTSB will be asking whether this was done.
The news last night had an interview with a Coast Guard official who visited the stricken vessel’s sister ship, which had the same/similar berthing layout including the emergency exit from the berthing deck. They showed the emergency exit on this boat, and it was a small hatch that required significant contortions to access and pass through. The Coast Guard Official expressed doubts about the utility of such an exit.
Could it be an electric BBQ?
Friends of mine who have been on that boat said that it was part of the safety briefing. Somewhere I saw a picture of the hatch and it would be next to useless in getting a lot of people out quickly in a fire situation. I was probably more designed for a sinking boat.
The boat got yearly Coast Guard checks and passed all of them. I can’t sat whether some of the things that passed were because they were grandfathered in. Once the cause is determined, we may well see some changes.
they said on the news that it’s a requirement that a crew member be on watch at all times. Probably more concerned about sinking or getting hit by other boats.
It wouldn’t surprise me if emergency systems are revisited. It might be something as simple as locating more fire suppression switches around the boat and turning off flammable gas tanks at the source when not in use and venting the bulkheads continuously.
I just read an article from USA Today that the victims are believed to have died due to smoke inhalation. So the limited points of egress wasn’t the reason for their deaths.
There’s a lot of talk about overheating lithium batteries as being potentially the point of origin for the fire. Given the extra layers of scrutiny those already get for air travel, if they played a part in this tragedy, I wonder what the reaction would be.