Titanic tourist submersible goes missing

[Kd9truck]

Originally Posted by Statistical

The actual experts on the scene based on the location of the wreckage and size of the debris field estimate it imploded around the time communication were lost. We are unlikely to ever know more than that.

A 3800m tether are you serious?

There will be no bodies recovered. Can you mentally visualize what 5500 psi would do to anything other than a pressure vessel. Pounds per square inch. As in almost 3 tons not 3 tons in total 3 tons on every square inch of surface. Essentially putting a human sized object into a 3000 ton hydraulic press.

Respectfully Sir, they laid fiber optics cables across the bottom of the Atlantic, the long line fishing vessels tow 25 miles of line. I spent 80 hours on the construction of an aramid fiber known by its proprietary name, Technora….I did this before I helped integrate it into a personal escape system PSS for the second largest fire municipality in the world I think it would be a good candidate. Guys was a billionaire. Nobody tapped that guy on the shoulder ? unfortunately A Billionaires life was worth 250k.
No plan B
It’s a tragedy

[Chotu]

Originally Posted by Statistical

One unknown decision is why carbon fiber. There have been dozens of deep sea submersibles that all together have to have made hundreds of dives over the last 60 years and none have failed catastrophically at depth like this. None also used carbon fiber. Yes carbon fiber is strong but so is steel if you use enough. Carbon fiber is light but hard to see how that is an advantage here. The boyancy is coming from the low pressure air inside the pressure vessel which is a lot lighter.

Obviously they had a reason otherwise they would have just used steel but not sure what it would be.

Like I said up thread, I guarantee you will find shredded carbon fiber and the titanium end caps will be just fine. 100% the carbon fiber failed.

In addition, using two different types of materials in something that cycles with 5500 pounds per square inch on it? Not a good idea. They have different expansion and contraction rates. Using two different materials in this application is just asking for trouble in my opinion.

[Pete7]

Originally Posted by Kd9truck

It’s a tragedy

True.

Perhaps we should leave the RMS Titanic to rest in peace. It is after all a grave.

[Uncle Bob]

Originally Posted by Pete7

True.

Perhaps we should leave the RMS Titanic to rest in peace. It is after all a grave.

Wholeheartedly agree.

Could it possibly be, now that the outcome is known, time to allow this thread to also rest in peace?

[Franziska]

Originally Posted by Simi 60

Let that sink in.

Hi, I'm with you on that.
Especially now when it comes to recovery.

Thing is the poor people on the fishing boat had virtually no chance of being alive once it sank and had no lobby either.

The folks in the sub might have been alive (now we seem to know they were not) and had many contacts to important people.

[RaymondR]

"The boyancy is coming from the low pressure air inside the pressure vessel which is a lot lighter."

Nope, the buoyancy comes from the displacement of the water. I think it's called "Archimedes Principal".

I suspect they used carbon fiber to exploit the weight reduction. Early bathyscapes used a big tank of petrol to achieve neutral buoyancy because of the massive weight of the steel pressure vessel.

[cyan]

The comms were sketchy, the controls were sketchy, but most importantly, the mechanical design was obviously sketchy, as Chotu pointed out.
There are many safe submersibles that are also certified. This one was not. This one was rogue, experimental and dangerous. The late CEO, Stockton Rush, was warned. If only the passengers were better informed...

March27, 2018
Oceangate Inc
1205 Craftsman Way, Suite 112
Everett, WA 98201

Dear Stockton,

This letter is sent on behalf of our industry members who have collectively expressed unanimous concern regarding the development of TITAN and the planned Titanic Expedition. Our apprehension is that the current experimental approach adopted by Oceangate could result in negative outcomes (from minor to catastrophic) that would have serious consequences for everyone in the industry.

The MUV industry has earned itself an enviable safety track record over the past 40 years. This is partly due to the diligent engineering discipline and professional approach exercised by members of the industry, but also due to the collective observation of (and adherence to) a variety of safety standards.
This reputation is solid because it was hard won over many years of diligence application and has resulted in a safe and successful record of operation. Our members are all aware of how important and precious this standing is and deeply concerned that a single negative event could undo this.

Your marketing material advertises that the TITAN design will meet or exceed the DNV-GL safety standards, yet it does not appear that Oceangate has the intention of following DNV-GL class rules. Your representation is, at minimum, misleading to the public and breaches an industry-wide professional code of conduct we all endeavor to uphold.

We do all agree that a performance-based testing program for design verification is a recognized and valid approach to new technologies. However, we recommend that at a minimum you institute a prototype testing program that is reviewed and witnessed by DNV-GL (or ABS). While this may demand additional time and expense, it is our unanimous view that this validation process by a third-party is a critical component in the safeguards that protect all submersible occupants.

Together we are all beneficiaries of the excellent safety record of MUV operations over the years; but each one of us is also a steward with a responsibility to sustain this achievement. We would be grateful if you could confirm that Oceangate can see the future benefit of its investment in adhering to our industry accepted safety guidelines and protocols for ultimate success and that of the MUV community.

https://int.nyt.com/data/documenttoo...b3764/full.pdf

[GordMay]

Originally Posted by Kd9truck

Hi Pete,
Good question

Can I ask you do you know it was instantly? May there have been warning sounds that would have alerted them? ...

Titan was equipped with a real-time acoustic monitoring system, which OceanGate claimed, could detect the onset of buckling, in the carbon fiber hull, prior to catastrophic failure.[1] Stockton Rush held a patent on the system.[2]

[1] ➥ https://www.smithsonianmag.com/innov...nic-180972179/

[2] ➥ https://worldwide.espacenet.com/pate...3DUS11119071B1

[jsal]

Originally Posted by Statistical

There will be no bodies recovered. Can you mentally visualize what 5500 psi would do to anything other than a pressure vessel. Pounds per square inch. As in almost 3 tons not 3 tons in total 3 tons on every square inch of surface. Essentially putting a human sized object into a 3000 ton hydraulic press.

Based on how violent an implosion is and also the amount of heat that gets generated, there's no way we're going to be finding any bodies.

All of this seems like it could've been so avoidable if Stockton Rush wasn't trying to be such a maverick. In a way, it's a bit fitting that the CEO who refused to heed multiple calls for concern is down there with a captain who refused to heed multiple iceberg warnings.

Such a shame.

[boatman61]

From an old interview with the owner it emerged that the 7inch thick acrylic viewing screen was visibly squeezed as the depth increased.. an uneducated guess is that is what gave.
Its been subjected to that pressure several times previously and judging by the cavalier acknowledgement of 'rule bending' it's unlikely it was switched out after each dive but, it's also unlikely we'll ever know for sure.
Now..it might sound inhumane but like the migrants, you pays your money, you take the chance.
No one is forced into it, conscious decisions.

[Franziska]

Originally Posted by boatman61

From an old interview with the owner it emerged that the 7inch thick acrylic viewing screen was visibly squeezed as the depth increased.. an uneducated guess is that is what gave.
Its been subjected to that pressure several times previously and judging by the cavalier acknowledgement of 'rule bending' it's unlikely it was switched out after each dive but, it's also unlikely we'll ever know for sure.
Now..it might sound inhumane but like the migrants, you pays your money, you take the chance.
No one is forced into it, conscious decisions.

And one might add, according to the BBC Stockton once said, if you don't break things you have not innovated enough. He related that to fully certified industrial subs not failing catastrophic for many years.

Not sure that is the right attitude when carrying paying tourists.
I have no problem with that attitude if it comes to test pilots on experimental vehicles.

No passenger vessel, charter boat or similar would get away with that attitude.
In a way his guests signed up to be high net worth guinea pigs.

[CaptTom]

I think, now that the outcome is (more or less) known, this is the right time to talk about it.

First, focusing on this one incident should not be considered disrespect toward all the migrants and others who face tragedy every day. This was a suspense story. We didn't know what happened. We didn't even know the names of the people involved when the story first started circulating. So it wasn't celebrity status which caught our attention. It was the mystery of what happened, how it happened, why it happened. We all want to learn from others' mistakes, as we should.

I'm learning a lot from this discussion. I wasn't planning a trip in an un-certified deep-dive submersible. But I'm sure some nugget of information about this case will become useful some day.

[neilpride]

One question I have is that the 2 cones were supposed to be titanium, and the center tube? CF coated titanium, or completely in CF? because as far as I know CF is great in tension, but not in compression.

I mean that every time that sub goes down to 3800 m, the CF hull undergoes compression and expansion, and the only thing that has the filaments enduring that suffering is the matrix resin, so in repeated cycles I do not know how they can find out that there is no delamination.

Titanium is more than proven in subs.
CF ?

[GordMay]

The compressive strength of a carbon fiber composite may be a system property, which is influenced by a combination of various structural features, [rather than by any single feature], in addition to a material property.

[MicHughV]

Interestingly, from I've gathered so far, is that the US Navy seemed to already know the fate of this vessel back on Monday, due to their "secret" underwater monitoring system.

But this reminds me of the space shuttle Challenger explosion back in 1986 shortly after take off. One little mishap is all it takes to start a chain reaction in a highly stressed machine in a basically unfriendly environment, regardless of all the technical know how involved in the design.

No doubt, more information will be coming as time passes by, but seeing as the debris field, is basically out of reach, any conclusion is likely to be subjective.