As an ex-submariner I have been following this and it does not sound good. First it has been way too long without hearing from teh sub, they cannot stay underwater very long without surfacing for clean air, since they are a diesel sub. It has now been reported that the last communication with them they said something about a battery short. Now it has come out that the ears in the ocean have heard a loud explosion, non-nuclear and most likely from the sub. The water in the area is about 10,000 feet deep. There is no way this type of sub can possibly go that deep without being destroyed.
I still hold out hope, but I very seriously doubt that anyone will return from the sub. They may or may not be able to find it too. It is one of the hazards of being a submariner.
Ex-submariner here too. Once I heard that it had been 3 days since anyone heard from them I knew they were goners. I don't think there is any hope for them at this point....I hope I'm wrong, but I doubt it.
The scariest thing I went through was after a minor refresh (we were in dry dock for 3 months). We went out for 'angles & dangles' and at test depth running at flank speed a fire broke out and filled the sub with smoke. I was a newbie, so I was oblivious to the real danger until I saw the panic in the eyes of people who had been aboard for years. Luckily for us it was just some paper that got sucked up into the ventilation ducts and hit a heater, but it was a pretty tense 10-15 minutes!
I had a few too many exciting moments on the sub. Three times below test depth was pretty bad, but the last patrol someone shot a torpedo at us just as we left Guam. Quiet was a lot better.
I am going to take a stab at what happened. One report said that the last transmission from the sub was that they had a battery short. Most likely they had a cell reverse while running pretty hard on the battery. That causes that one cell to have the whole voltage across it like as if it was being charged at extremely high voltage. This would generate a lot of both Oxygen and Hydrogen, which could then explode. It would not be the first time a battery cause a sub to go down.
I had a few too many exciting moments on the sub. Three times below test depth was pretty bad, but the last patrol someone shot a torpedo at us just as we left Guam. Quiet was a lot better.
I am going to take a stab at what happened. One report said that the last transmission from the sub was that they had a battery short. Most likely they had a cell reverse while running pretty hard on the battery. That causes that one cell to have the whole voltage across it like as if it was being charged at extremely high voltage. This would generate a lot of both Oxygen and Hydrogen, which could then explode. It would not be the first time a battery cause a sub to go down.
Makes me wonder if there was anything in place to isolate/bypass the cell, in case of such an event. (I have done telecommunications work using large banks of cells. We didn't have anything like that, but I wouldn't be surprised if the technology existed - especially nowadays. But then I never heard of such an occurrence, either. in the telecom world.)
With that said, I have to assume that the resulting explosion, if that's what it was, would be severe enough to breach the hull. I certainly can imagine some awful ways to meet my maker, but such an event would have to be near the top of the "horrible" list. My heart goes out to all who are affected by this.
Makes me wonder if there was anything in place to isolate/bypass the cell, in case of such an event. (I have done telecommunications work using large banks of cells.lecom world.
The only way to bypass the cell would be to jumper around it. Big jumpers too, since even on a Nuclear powered boat like I was on it was about 260 VDC and 6500 amp hours for the battery.
This article was written by someone without much knowledge. They are making a big deal out of cutting the boat in half to replace the batteries and such. That is a normal occurrence on all subs when they are retrofitted. They have to cut holes in the hull to get things out. There is no way to fit any of the machinery through the hatches.
And yes, I do believe they were probably crushed in the depths. Most subs don't go very deep. Maybe a thousand feet or so at the most. And the depth there is over 10,000 feet. At 44 lbs/square inch for every 100 feet of depth, it gets to high pressure fast. If the battery blew it probably breached the hull and they would go down fast. And there would be nothing they could do to stop it.
The news is reporting that the last communications with this sub was that they were snorkeling on the diesel and they sucked in water, which went through the ventilation system and shorted out the cabling to one of the batteries. They then switched off of that battery and were on the other one, But it appears that they then had an explosion, which could have been from one of the batteries. Sad, sad story.
It is starting to look like my original thesis about having a battery problem causing a battery cell to reverse is the likely problem. As seen in this report towards the end.
This is copy pasted from a submariner on Reddit, it’s a description of what would happen at crush depth. It is facunatigly terrifying:
Reaching crush depth wouldn't be a slow crushing. Once the first deformations appear in the pressure hull, the whole thing caves very very fast, likely over the course of a couple seconds at most, depending on the pressure when it finally gives (44psi per hundred feet, at 1800 ft would yield almost 800psi, that's a lot of pressure, and a massive release of energy once the hull finally gives.).
The strength of the hull comes from its shape more than material strength (though that does play a massive factor).
What feels slow, and would feel like an eternity, would be everything that leads up to crush depth.
Well before you reached crush depth, you'd know you were doomed. You'd be able fight the ship for a while, trying to restore hydraulics for control surfaces, high pressure air to blow out the ballast tanks, fighting to manually close ballast tank vents if they've been pushed out of position, trying to restore propulsion any way you can, fighting the fire that may have destroyed your battery and filled your world with chlorine gas and smoke. All this activity and rush feels fast, it may be 15 minutes, it may be 2 hours, but all it does is give you hope. Then when you're exhausted and everybody is looking around in a moment of calm, the last battle lanterns will fail and you'll spend the rest of your life in a darkness you can't possibly have imagined until that moment. You hear a lot of creaking and groaning, growing louder and more insistent over the course of a few minutes. Suddenly, you feel, more than hear, a terrible rending of metal, and your 14 psi world becomes damn near 800 in barely a few seconds, and you never hear anything again.
Threedog - A lot of things that are in the article that you quoted are true. The pressure is about 44 lbs per square inch for every 100 feet of depth in sea water. And if the sub was crushed by going too deep it would get to a certain point where it would collapse into itself. The point where it would collapse into itself would be at the bulkheads for the different compartments of the sub. And if the submarine was experiencing problems most of the hatches would have been shut, maintaining the integrity of each compartment. So it might collapse in stages as it got deeper.
Having said all of that, this article explains the explosion. The explosion from these reports was from a leak when they were snorkeling. The inlet valve is designed to shut if it touches the water. The inlet is on a mast so the sub can be submerged and still run the diesel. But, sometimes the sub transients in depth and the snorkel will open and close as the mast goes down into the water and back up. In this case it sucked in way too much water and shorted out one of the battery's cables. This causes a huge electrical draw on the battery and when that happens it can reverse the weakest cell. It would be like electrically connecting a single cell across the DC input. So instead of seeing about 2.88 VDC across the cell it will see maybe 260 VDC. This then makes the battery act as an oxygen generator and it will disassociate the water into hydrogen and oxygen at different poles. This can generate a huge amount of hydrogen and oxygen in a short time. It is one of the worst nightmares for a submariner. It only takes a spark then to ignite it in an explosive manner.
When this explosion happens it will blow a huge hole in the side of the sub and it will start taking on water rapidly, and there is no way to stop it if the hole its too big. So you would already have a compromised hull, leaking rapidly causing the sub to go deep fast. And as it would go deeper it would build up the pressure around the hull as explained before. If the ship was buttoned up with the bulkhead door latched of dogged down then as it went deeper the pressure would increase and eventually the hull would break at the bulkhead joints and collapse into themselves.
It would take at least 10's of seconds to go from normal depth to crush depth even with a battery explosion. So not only would you be busy trying to plug the hole from the explosion, if it even was possible. You would know you were on your way down to your death.
This was always something that is in the back of the mind or any thinking sub sailor.
Myself, I had three occasions where we went past test depth. One was due to a mechanical problem and one was due to incompetence and stupidity and the last one was a death wish.
