Missing Titanic tourist sub

[Nuke]

1 hour ago, SunlitZelkova said:

With this attitude why should we even care? Why should we waste tax dollars to search? This is just the underwater equivalent of someone getting hit while crossing the street.

I do not believe it was well engineered. An employ raised concerns about safety and was fired.

On a separate note, I have seen some takes on Twitter saying it is only a matter of time before some space tourism company does the same thing. What are your guys' thoughts on that? I disagree because there is better regulatory oversight for spaceflight. Rather than being akin to the loss of the Titan, any space tourism disaster will probably end up being more Challenger-like.

taking risks on a long enough timeline will inevitably lead to deaths. it is unavoidable. its a matter of personal responsibility to accept any risks you may chose to take. if you are handed a waiver it usually means that a corporate bean counter figured out the death rate for a given activity, figured out that it is not zero, how much it would cost per instance, determined the cost over time, and decided that it could not afford to engage in that activity if they had to pay the price of such inevitabilities. in other words, a safe world is a boring world. we all have to take measured risks, driving, flying, eating sushi from the convenience store, dating that one freaky girl everyone else is afraid of, survival demands it. some people are willing to take a little more than others. and im sure everyone who got into that sub was aware of what they were doing.

[monophonic]

17 hours ago, Gargamel said:

I can’t think of a membrane that would survive those depths and have a reliable fail time.  

I don't think the membrane would have to bear the full pressure. It would just have to cover the water sensitive bit(s) and transfer the force to the backing materials while dissolving slowly. Still hard enough a problem at 3800 meters.

16 hours ago, tater said:

Again, submarines are above and beyond any normal rescue though. Requiring commercial operators to have insurance (or money in escrow) to cover such a costly rescue is different than requiring Joe Blow to do the same for a sailboat (which I am not suggesting). Just seems like a different situation given the inherently higher risk of these operations, combined with their commercial nature. Requiring insurance is not strange, cars have to have insurance already. The plus in this case is that high insurance costs incentivizes more attention to safety, and perhaps even better testing to demonstrate safety to achieve lower insurance costs.

Yes, cars are required to have insurances. Yet the emergency services do not just pack up and return to station if at the crash site it turns out the car did not have an insurance. Putting human life above any financial concerns is a moral choice, and I am well aware some people and nations draw a line there at quite varied levels.

16 hours ago, Lisias said:

Assuming they are still alive, this is merit of the submarine's project.

Au contraire from stupid people criticising the use of a of-the-shelf game controller from a famous game manufacturer, the thing was well engineered. There're lots of safeguards on it (granted, perhaps a few more are needed).

However… exploring the bottom of the sea is as dangerous as exploring the space - lots and lots of things can go wrong, and a single one will ruin your day and probably end your life. No matter how well you engineer something, sooner or later it will fail due something no one had thought of, or plain tear and wear. It's unavoidable that an accident would happen one day in the same sense that's unavoidable sooner or later someone will die on space: hell, we can't prevent people from dying while crossing streets!

An untested safeguard does not guard safety. I have no documents on how those were tested, but given the bits that have come to light I am not confident. Worst - and most telling - I think is the "let's routinely operate this hatch window at 300% the certified maximum depth" mindset. I doubt any of the safeguards had been properly end-to-end tested, definitely not at real operating conditions i.e. from 3800 meters depth. That would have required multiple trips to that depth and sitting there until the safeguards bring the sub to the surface. At least one trip per combination of safeguards required to trigger for an ascent to get forced.

1 hour ago, Nuke said:

taking risks on a long enough timeline will inevitably lead to deaths. it is unavoidable. its a matter of personal responsibility to accept any risks you may chose to take. if you are handed a waiver it usually means that a corporate bean counter figured out the death rate for a given activity, figured out that it is not zero, how much it would cost per instance, determined the cost over time, and decided that it could not afford to engage in that activity if they had to pay the price of such inevitabilities. in other words, a safe world is a boring world. we all have to take measured risks, driving, flying, eating sushi from the convenience store, dating that one freaky girl everyone else is afraid of, survival demands it. some people are willing to take a little more than others. and im sure everyone who got into that sub was aware of what they were doing.

As long as everything they say to get you sign said waiver is 100% true, that's ok. As soon as something deviates from truth that waiver becomes evidence of foul intent. Do you think they wrote in the waiver that they totally dismissed 60 year old safety lessons and operate safety critical hull pieces way outside their  certified operating conditions? I doubt anyone in that sub was at all aware of what they were really doing - least of all the CEO.

[magnemoe]

2 hours ago, DDE said:

OceanGate apparently chose jurisdictions that had nonexistent regulatory oversight. Similar shenanigans are likely to ensue in space tourism; attempts to impose the launching country's safety standards could be repelled by whinging over "denial of access to space to developing nations".

Wouldn't want to keep Elbonia's space program down!

Now ocean going ships can generally go to any port so its an legal tricks to register them in in countries with no taxes for shipping and few to none regulations. 
Yes other countries can deny the ship access to its ports but this is rarely done.

Space tourism require an spaceport who can launch an Soyuz sized rocket at an minimum. Now for suborbital trips things is much simpler but they still need to operate out of the hosted country. 
If they operate from another they have to follow that country's rules. 

[Lisias]

7 minutes ago, monophonic said:

An untested safeguard does not guard safety. I have no documents on how those were tested, but given the bits that have come to light I am not confident. Worst - and most telling - I think is the "let's routinely operate this hatch window at 300% the certified maximum depth" mindset. I doubt any of the safeguards had been properly end-to-end tested, definitely not at real operating conditions i.e. from 3800 meters depth. That would have required multiple trips to that depth and sitting there until the safeguards bring the sub to the surface. At least one trip per combination of safeguards required to trigger for an ascent to get forced.

That's the problem I see with the current "safety mindset". 737 MAX had all the documentation demanded by FAA, and still...

People just don't understand that "certified limits" are just it: limits that the manufacturer bored to certify, they just don't implies on operational limits. People working on manufacturing knows that it's not rare that whatever you sell is able to sustain way more abuse than certified, but since the customers are not willing to pay for a more thoroughly certification process (as the current certified limits are enough). The whole experimental thingy has its name for a reason.

Proof of concept? I have a MacMini working fine for 12 years. I still use that Mac Crap for work, because it's good enough and it had survived my last rig I had bough to replace it due "certified limits concerns". Go figure… 

(And not, this is not an absurd comparison,  I'm talking about manufacturing: the same Six Sigma process that can be used on computers can be used on submarines).

I'm not trying to pull any dirt under the rug, but first we need to know about the dirt.

Unless you are some authority on the field, the fact you don't have any documents or have doubts means squat. And if you are an authority on the field, then you are accomplice of the problem you are denouncing, and I don't see a reason to take what you say too much seriously due conflict of interest.

If the thing was experimental, if everybody onboard were perfectly aware of the risks, and still decided to go - well, it was their choice: it's a free World and people are allowed to make such choices.

I will agree with you, however, if known flaws were being covered up for the sake of profit - that would be a criminal offence to my eyes.

[monophonic]

1 hour ago, Lisias said:

That's the problem I see with the current "safety mindset". 737 MAX had all the documentation demanded by FAA, and still...

Well, you see, 737 MAX had all the documentation, but the hardware did not match the documentation. Boeing paid 2,5 billion USD for that fraud.

1 hour ago, Lisias said:

People just don't understand that "certified limits" are just it: limits that the manufacturer bored to certify, they just don't implies on operational limits. People working on manufacturing knows that it's not rare that whatever you sell is able to sustain way more abuse than certified, but since the customers are not willing to pay for a more thoroughly certification process (as the current certified limits are enough). The whole experimental thingy has its name for a reason.

Certified limits are exactly that, indeed. Especially they don't imply that the device will take any more abuse than certified. It is not rare that it will, but that's only when it is cheaper to put in the extra margin in the design than reduce the variability in the manufacturing process to negligible levels. There is no guarantee that the unit you got will take any extra. Especially not in a small rate niche product manufacturing like deep sea viewport dome windows.

2 hours ago, Lisias said:

Proof of concept? I have a MacMini working fine for 12 years. I still use that Mac Crap for work, because it's good enough and it had survived my last rig I had bough to replace it due "certified limits concerns". Go figure… 

Compared to the piles of MacMinis that were dumped in the first year because they just broke down for no discernible reason? Congratulations, you won the hardware lottery! Wanna bet your life on repeating that?

2 hours ago, Lisias said:

(And not, this is not an absurd comparison,  I'm talking about manufacturing: the same Six Sigma process that can be used on computers can be used on submarines).

How much "Measure" and "Analyze" can you do when your entire production to date is two units of differing designs? Six Sigma is geared for mass production. Submarines are not mass production, deep sea subs especially.

2 hours ago, Lisias said:

I'm not trying to pull any dirt under the rug, but first we need to know about the dirt.

There's the proven hostile action against employee who raised safety concerns. There are other bumps on the rug, and that prior example assigns increased probability on those being more dirt.

2 hours ago, Lisias said:

If the thing was experimental, if everybody onboard were perfectly aware of the risks, and still decided to go - well, it was their choice: it's a free World and people are allowed to make such choices.

I will agree with you, however, if known flaws were being covered up for the sake of profit - that would be a criminal offence to my eyes.

At least we agree on the points that matter. Although I would count covering up lack of measures against unknown flaws as criminal too.

[Lisias]

58 minutes ago, monophonic said:

Well, you see, 737 MAX had all the documentation, but the hardware did not match the documentation. Boeing paid 2,5 billion USD for that fraud.

This was a contributing factor, but the root cause of the tragedy was the MCAS, and this crap was certified by FAA and it matched exactly the documentation aproved by FAA.

And I'm not seeing anyone sueing the FAA for fraud. Something to think about.

 

1 hour ago, monophonic said:

Certified limits are exactly that, indeed. Especially they don't imply that the device will take any more abuse than certified.

The point you are ignoring is that it doesn't implies it will not neither.

In true, for any certified limit you can expect from 50% to 100% tolerance for abuses as a safety guard for future manufacturing problems as low graded material being leaking into manufacturing for a reason or another.

Additionally, the certification is done using the weakest link of long chain of parts and materials. A part of the machine can be certified to be used on harsh conditions when matched with better side components.

This bureaucratic mindset is exactly the reason that leaded Boeing to fail on StarLiner, while SpaceX succeeded on Dragon doing exactly the opposite.

 

1 hour ago, monophonic said:

Compared to the piles of MacMinis that were dumped in the first year because they just broke down for no discernible reason? Congratulations, you won the hardware lottery! Wanna bet your life on repeating that?

Nope. I just blhad bought a 2012 MacMini, two years before the thing going the Dodo way.

You see, MANUFACTURING. 2014 MacMinis are a completely different beast than 2012.

And yeah, I learnt that the expensive way: by loosing my time on a 2014 one.

Both passed the manufacturer certification standards, but only the older passed on mine.

 

1 hour ago, monophonic said:

How much "Measure" and "Analyze" can you do when your entire production to date is two units of differing designs? Six Sigma is geared for mass production. Submarines are not mass production, deep sea subs especially.

Dude... Six Sigma is a quality assurance process... please do some diligent research before throwing weak arguments on a (until now) serious conversation...

 

 

[Nuke]

4 hours ago, monophonic said:

As long as everything they say to get you sign said waiver is 100% true, that's ok. As soon as something deviates from truth that waiver becomes evidence of foul intent. Do you think they wrote in the waiver that they totally dismissed 60 year old safety lessons and operate safety critical hull pieces way outside their  certified operating conditions? I doubt anyone in that sub was at all aware of what they were really doing - least of all the CEO.

failing to disclose all the risks is fraud. lets see their waiver hold up in court if that happens. not to say that the involved parties wouldn't find some other way to sue the sub operators. or that even the would be rescuers wouldn't seek compensation for their efforts (especially considering there is at least one rich dude on board). one thing is sure, the lawyers will get rich off of this. 

[tater]

7 hours ago, SunlitZelkova said:

With this attitude why should we even care? Why should we waste tax dollars to search? This is just the underwater equivalent of someone getting hit while crossing the street.

We still send an ambulance to scoop up the victim (and maybe people to hose off the street).

That said, the expense of multi-day air/sea ops by the navy and coast guard of 2 countries is a nontrivial expense. As I think I said up the thread, there should be some way that commercial operations compensate the countries for those expenses, at least for operations that are in excess of normal maritime activity.

 

7 hours ago, SunlitZelkova said:

I do not believe it was well engineered. An employ raised concerns about safety and was fired.

Depends on how it was lost. I still tend to think it never made it to the wreck and imploded, in which case yes. If the pinger failed and they continued the dive anyway, that's a combination of not having a backup (poor design), and bad decision-making. The latter is very related though, as it points to a lack of a robust safety culture in the company.

8 hours ago, SunlitZelkova said:

On a separate note, I have seen some takes on Twitter saying it is only a matter of time before some space tourism company does the same thing. What are your guys' thoughts on that? I disagree because there is better regulatory oversight for spaceflight. Rather than being akin to the loss of the Titan, any space tourism disaster will probably end up being more Challenger-like.

The will certainly happen at some point for space tourism. Regulation is not the solution, IMO. Not until it is not a touristic stunt, but actual travel. Should they do point to point—then it gets regulated like an airline. A few randos to space? Dangerous and risky. As I pointed out above, a number of the tallest peaks on Earth (the 8000m peaks) have huge mortality rates (deaths per summit). Literally Russian roulette levels of risk and people do it every year. And yeah, the space risk will be live streamed.

The first stranded mission someplace will be very much like the last few days, but we'll have coverage, and no chance of rescue.

[tater]

4 hours ago, monophonic said:

Yes, cars are required to have insurances. Yet the emergency services do not just pack up and return to station if at the crash site it turns out the car did not have an insurance. Putting human life above any financial concerns is a moral choice, and I am well aware some people and nations draw a line there at quite varied levels.

In my example, yeah, the US/Canada would have to be willing to pull the plug on rescue ops for uninsured commercial operators. Again, I am suggesting a rule explicitly for submarines, not for surface vessels. We've been doing rescues on surface vessels forever, that's fine. The difficulty level is orders of magnitude higher with a missing sub (so tiny). The insurance is only for the sub, else they'd get the same surface search any other wreck would get. Air and sea assets using surface search radar, etc. Remember that this incurs nonzero risk to the aircrews. This entire search was completely fruitless after some time, BTW. They know how long to deploy some asset that could drop a 2+ mile line with an ROV to try and hook it to the vehicle, then lift 10,000kg. If that pull the trigger to pulling up the sub with zero delay was 24 hours, then the last 24 hours of search was 100% pointless. If you add slop to deploy, and actually have a few hours to work out issues it's longer. Realistically there was never any hope of rescue. It should be OK to do that math and tell everyone it's pointless.

OTOH, the navy/CG might want to do the search, it's good training. <shrug>

 

19 minutes ago, Nuke said:

failing to disclose all the risks is fraud. lets see their waiver hold up in court if that happens. not to say that the involved parties wouldn't find some other way to sue the sub operators. or that even the would be rescuers wouldn't seek compensation for their efforts (especially considering there is at least one rich dude on board). one thing is sure, the lawyers will get rich off of this. 

I've seen a few people who went on the other dives to the wreck saying that the experimental nature was explicit, and that death was mentioned in the waiver multiple times. Course we all get trained to sign that stuff and ignore it with all the safetyism, I signed something like that for my kids at the trampoline park (a place that my wife thinks the orthopedic surgeon should set up a mobile clinic in the parking lot ).

One guy said he decided this sub was too dangerous, that all the others used a sphere to maximize strength. These people traded slight comfort to spread out with their lives.

[tater]

One thing is clear, the taxpayers should not spend a dime looking for the wreck or bother with recovery at this point.

We do so for wrecks where there is data that impacts the safety of others—airliner goes down in the ocean, for example—but this is not the case here.

[Lisias]

43 minutes ago, tater said:

One thing is clear, the taxpayers should not spend a dime looking for the wreck or bother with recovery at this point.

We do so for wrecks where there is data that impacts the safety of others—airliner goes down in the ocean, for example—but this is not the case here.

Not exactly… You see, the S&R teams costs a lot of money on training and equipment being used or not, the costs of one search itself besides pretty high for our humble standards are just a drop on the ocean that it's the overall budget for keeping these Search and Rescue teams operational.

Besides, jumping in on these high profile efforts has a pretty positive P/R to them, helping them to secure funding for the next fiscal year (too much time without accidents, politicians start to withdraw money from them and use it on things that would bring them votes).

If any of these guys manage to rescue the submarine with survivors, you can bet your mouse they will secure funding for 10 years - not to mention an increase on the applicants, that currently is their worst nightmare (very few people enjoys the heavy training and the boring routine of S&R, not to mention the meagre payment). And lots and lots of Fundraising events from grateful tycoons.  

[steve9728]

I missed the news but after the summary of information from various media, I have these points of confusion:

1. How did they get a deep dive qualification for something of this engineering quality that is almost like a toy? Frankly speaking, it should not even be allowed to go to sea.
2. How does this company market this toy-like thing, and get the rich people on board? (And the rich people really f* buy it??)

The only good thing about this submarine is that it can't screw those of us who aren't that rich.

[tater]

42 minutes ago, Lisias said:

Not exactly… You see, the S&R teams costs a lot of money on training and equipment being used or not, the costs of one search itself besides pretty high for our humble standards are just a drop on the ocean that it's the overall budget for keeping these Search and Rescue teams operational.

Besides, jumping in on these high profile efforts has a pretty positive P/R to them, helping them to secure funding for the next fiscal year (too much time without accidents, politicians start to withdraw money from them and use it on things that would bring them votes).

If any of these guys manage to rescue the submarine with survivors, you can bet your mouse they will secure funding for 10 years - not to mention an increase on the applicants, that currently is their worst nightmare (very few people enjoys the heavy training and the boring routine of S&R, not to mention the meagre payment). And lots and lots of Fundraising events from grateful tycoons.  

True, the training value alone is nonzero I guess.

 

[tater]

2 minutes ago, steve9728 said:

I missed the news but after the summary of information from various media, I have these points of confusion:

1. How did they get a deep dive qualification for something of this engineering quality that is almost like a toy? Frankly speaking, it should not even be allowed to go to sea.
2. How does this company market this toy-like thing, and get the rich people on board? (And the rich people really f* buy it??)

The only good thing about this submarine is that it can't screw those of us who aren't that rich.

They clearly managed to market it well enough to get some customers. As for "certification," who would certify it? They could literally flag the vessel form any country they liked, find one that wants the fee, and done. This is a caveat emptor thing IMO. Do your homework before risking your life.

That said, as I posted above, this sort of trip is grossly less dangerous than high level Himalayan mountaineering. Up to ~1 in 4 die (vs successful summits, vs total participants it's <1%, think for peaks over 6000m is more like 10%). Base jumping is ~1.6% mortality.

 

[Minmus Taster]

An ROV has found a field of debris on the seabed. It's over, at least they probably didn't feel it.

[Kerbart]

4 minutes ago, Minmus Taster said:

An ROV has found a field of debris on the seabed. It's over, at least they probably didn't feel it.

Could there be any other vessels that sunk there in the past, responsible for a debris field?  Not familiar with the Northern Atlantic there, but it's not inconceivable that it's just from a ship that sank there, say, a hundred years ago?

[Minmus Taster]

1 minute ago, Kerbart said:

Could there be any other vessels that sunk there in the past, responsible for a debris field?  Not familiar with the Northern Atlantic there, but it's not inconceivable that it's just from a ship that sank there, say, a hundred years ago?

It was found near the wreck of the Titanic but it's implied that this is a new field of debris. The Titanic's debris field is very well studied;

Spoiler

 

[Gargamel]

2 hours ago, tater said:

That said, the expense of multi-day air/sea ops by the navy and coast guard of 2 countries is a nontrivial expense. As I think I said up the thread, there should be some way that commercial operations compensate the countries for those expenses, at least for operations that are in excess of normal maritime activity.

And as I said up thread, there is such a system.    If the rescue is required by negligence or such, then they do get billed.   Regardless of what size of boat.    Did you try to cross the Pacific in a regular canoe?    Yeah you’re getting billed.    Did you start a company to take tourists on a submarine and it might have been lost due to poor design?    You’re getting billed.   
 

After.    
 

There’s no scenario where we as humans should ever not send an emergency response to those in need.   
 

If the insurance company didn’t do their due diligence and make sure the proper risk assessments and coverage amounts are in place, that’s on the insurance company, not the client nor the  regulating country.  

[steve9728]

Deep-sea creatures: thanks for the gift of nature!

[Ryaja]

Rest In peace the members of this poor sub, you will be remembered.

[tater]

First, USCG report "debris field," so implosion.

 

36 minutes ago, Gargamel said:

After.    
 

There’s no scenario where we as humans should ever not send an emergency response to those in need.   

If Joe Blow takes a canoe across the Pacific, and gets billed... $2.4M for 24 hour air ops by 5 aircraft for 5 days at $4000/hr and can't pay, because he doesn't have $2400, much less $2.4M, nothing gets paid.

If a startup forms to take paying customers, and they in fact don't have the larger millions for mobilizing 2 navies and CGs for a few days, then the government takes what they can at pennies on the dollar because the company promptly declares bankruptcy?

Requiring insurance for such cases seems completely reasonable. This was NEVER an "emergency response" unless the thing was sitting on the surface. Surface search? Entirely reasonable, by all means, business as usual. Looking underwater? No, this was never reasonable, since I can't imagine a situation where a rescue was even possible. I think that if a commercial operation wants an unreasonable response, they should have to have the money sitting there (in cash, or insurance).

Even ignoring the (now incredibly likely) implosion on Sunday, they would have needed to know the location pretty much from the start to have any hope. ~900 miles from Boston, ~400mi from Canada. So even if all the required equipment was in Canada waiting to go—a solid day to get there. Then setting up for the rescue. From Boston? 2 days. Wasn't even reported til what. Sunday night? So if they new the exact location and deep sea rescue equipment... existed, then Monday night. Coming from the US, Tuesday night. Basically if they didn't have the location to within a few meters on Monday, no rescue was ever even remotely plausible.

I'm trying to think of another example where no rescue is possible, but you do rescue adjacent things anyway as an expensive show of concern—but the taxpayers end up footing the bill.

Edited June 22, 2023 by tater

[magnemoe]

1 hour ago, steve9728 said:

I missed the news but after the summary of information from various media, I have these points of confusion:

1. How did they get a deep dive qualification for something of this engineering quality that is almost like a toy? Frankly speaking, it should not even be allowed to go to sea.
2. How does this company market this toy-like thing, and get the rich people on board? (And the rich people really f* buy it??)

The only good thing about this submarine is that it can't screw those of us who aren't that rich.

They operate in international water registered in an country who has no regulations on stuff like this. 
At open sea you can do a lot stuff you can not to other places. Yes its limits as in you might be arrested in next port if you do serious crime, or fined if they detect you pollute or stuff but nothing regarding stuff like this until now. 
Now Canada and other will want to investigate and if they find that this thing was very unsafe they have an serious problem. 

As I understand this does not work like an standard submarine  with ballast tanks, it uses weights to sink then I assume they drop one weight near the bottom after two hours to get negative buoyancy. It also has short range so it has to be guided in by sonar messages from the mother ship, but this require the mother ship to track them all the way down so they can give course corrections like an wire guided torpedo. 
Yes it should work, well I assume they have internal guidance system and an sonar detecting the distance to the sea floor. The INS you will get is wrong if the mother ship position for you is very different from it. The sonar you know don't work then you hit the seafloor unless you have two systems. 

[kerbiloid]

19 minutes ago, tater said:

First, USCG report "debris field," so implosion.

Or ex. But will never know.

[magnemoe]

2 hours ago, Lisias said:

Not exactly… You see, the S&R teams costs a lot of money on training and equipment being used or not, the costs of one search itself besides pretty high for our humble standards are just a drop on the ocean that it's the overall budget for keeping these Search and Rescue teams operational.

Besides, jumping in on these high profile efforts has a pretty positive P/R to them, helping them to secure funding for the next fiscal year (too much time without accidents, politicians start to withdraw money from them and use it on things that would bring them votes).

If any of these guys manage to rescue the submarine with survivors, you can bet your mouse they will secure funding for 10 years - not to mention an increase on the applicants, that currently is their worst nightmare (very few people enjoys the heavy training and the boring routine of S&R, not to mention the meagre payment). And lots and lots of Fundraising events from grateful tycoons.  

Who is true, now this will use fuel and increase aircraft maintenance costs, you can offset this to some degree by having to train less this month. 
But S&R teams has billed people doing illegal or obvious stupid stuff. 

Been in an old cemetery up in the north of Norway where fishing was the main occupation. Lots of the large tombstones with many names on them with the dame death date, usually later was an guesstimate. 
Only benefit is that they tended to be old. Fishing is still dangerous but loosing ships is rare. 

[Scarecrow71]

12 minutes ago, kerbiloid said:

Or ex. But will never know.

Even if there was an explosion, with the amount of pressure pushing on the sub, it would have imploded.