OceanGate Submersible Goes Missing During Titanic Dive

[mistermack]

That's interesting, and is in line with what James Cameron said on interview, that he had heard that in their last communication with the mother ship, the crew reported that they had "dropped the weights", and so were performing an emergency ascent. 

It seems hardly possible that the sub could descend too fast. The volume of air in the sub is fixed, barring collapse, so the bouyancy should be fixed. I can't think of many ways that the bouyancy could be compromised without catastrophic failure. Maybe an external mechanism had some sort of failure and let water in to a separate section? It seems hardly likely, and that probably wouldn't affect the integrity of the hull. 

Maybe the hull did delaminate early, and allowed some water in without collapsing? That seems hardly feasible. I can't really think of a likely or realistic scenario for this kind of loss of bouyancy at all. The thing weighed about 10 tons, so to affect it's bouyancy by a significant amount would take quite a bit of flooding.

[Genady]

How often the CEO was piloting the submersible? Did he do it this time to show how much he trusts its safety?

[mistermack]

If the transcript is genuine, I'm thinking that the sub had a separate section at the rear, and that began to flood, without initial failure, causing the error messages and the too fast descent. That's if it's genuine. It does have a genuine ring to it. 

[swansont]

14 minutes ago, mistermack said:

The volume of air in the sub is fixed, barring collapse, so the bouyancy should be fixed.

Water density increases under pressure. The vessel itself would decrease in volume (bulk modulus isn’t infinite)

https://water.lsbu.ac.uk/water/water_density.html

[Genady]

18 minutes ago, swansont said:

Water density increases under pressure.

This would increase rather than decrease the submersible's buoyancy, wouldn't it?

[TheVat]

On 6/29/2023 at 6:03 PM, Genady said:

In such a short time the system perhaps did not reach thermal equilibrium, so the incineration might be not total. Some DNA might be found.

In tooth pulp, very likely.  (I'm a bit late catching up with this thread)

[swansont]

32 minutes ago, Genady said:

This would increase rather than decrease the submersible's buoyancy, wouldn't it?

Yes. But as long as the compression of the submersible’s material and water are not the same, the effects won’t cancel.

[mistermack]

The effect is a bit of a red herring anyway. It's likely to be tiny, in either direction, and would be accounted for in the design, and would have happened identically in all of the previous dives, so it's not going to have any bearing on an out-of-normal nearly double descent rate.  And in any case, the descent rate is shown as excessive, right from the start, when the pressure would have been much lower. 

If the transcription is genuine, the bouyancy/weight balance must have been seriously compromised early in the dive, and they should have abandoned descent far earlier. How they could be doing such a dive, and not be acutely aware of their rate of descent boggles the mind. 

But the transcription being genuine is a big if at the moment. 

[John Cuthber]

2 hours ago, mistermack said:

The volume of air in the sub is fixed,

No, it's not.
Submarines get squashed to a measurable degree- some would say an alarming extent- even when they are working properly.
 

 

2 hours ago, Genady said:

Did he do it this time to show how much he trusts its safety?

I suspect he did it because he enjoyed it.

 

2 hours ago, mistermack said:

It seems hardly possible that the sub could descend too fast.

It will if it leaks at all.
 

 

1 hour ago, TheVat said:

In tooth pulp, very likely.  (I'm a bit late catching up with this thread)

Is there any point?
Has anyone said the victims are not the "right" people?
DNA will confirm the identities of any bits of body that they find.
I guess that's useful in terms of labeling a coffin but I imagine the victims will be considered "lost at sea".

Anyway, I predict further empty speculation.

[Genady]

1 hour ago, John Cuthber said:

I suspect he did it because he enjoyed it.

 

1 hour ago, John Cuthber said:

Anyway, I predict further empty speculation.

 

[TheVat]

1 hour ago, John Cuthber said:

Is there any point?
Has anyone said the victims are not the "right" people?
DNA will confirm the identities of any bits of body that they find.
I guess that's useful in terms of labeling a coffin but I imagine the victims will be considered "lost at sea".

Anyway, I predict further empty speculation.

My post on the use of tooth pulp was simply a reply to another poster on the type of DNA that can survive almost any kind of calamity.  While I am not personally invested in bodily remains being found, I can understand their use in reconstructing what exactly happened.  I don't think those who perished will mind if their bits serve a scientific purpose.  I hope that speculation of mine is not too empty for you.  If it is, you are free to move along.  

[John Cuthber]

2 hours ago, TheVat said:

  I don't think those who perished will mind if their bits serve a scientific purpose. 

It's a lot easier to ask their next of kin...

[mistermack]

They still have the sales page online. Which I find a bit distasteful. Particularly the bit at the bottom about "recently featured in" :       https://oceangateexpeditions.com/     

 

[Endy0816]

On 7/6/2023 at 8:32 AM, Genady said:

How often the CEO was piloting the submersible? Did he do it this time to show how much he trusts its safety?

Reading online was apparently typical.

[studiot]

I don't know the details of the naval architecture of the Titan.

But it's design must be  (or perhaps should have been ?) subject to the same stability/bouyancy considerations as other submersibles.

The current speculation about the effect of loss of volume due to compression is relevant here.

A general submersible is compressed as it descends and the effects are neither negligible on bouyancy nor stability.

These are separate considerations.

In order to maintain stability the distribution of the variable mass component must be considered.

Some bouyancy force is derived not from Archimedes but from lift due to the motion of the hydroplanes.

These must be correct or the sub will enter an uncontrollable nose dive.

https://www.marineinsight.com/naval-architecture/understanding-stability-submarine/

[Endy0816]

10 hours ago, studiot said:

I don't know the details of the naval architecture of the Titan.

But it's design must be  (or perhaps should have been ?) subject to the same stability/bouyancy considerations as other submersibles.

The current speculation about the effect of loss of volume due to compression is relevant here.

A general submersible is compressed as it descends and the effects are neither negligible on bouyancy nor stability.

These are separate considerations.

In order to maintain stability the distribution of the variable mass component must be considered.

Some bouyancy force is derived not from Archimedes but from lift due to the motion of the hydroplanes.

These must be correct or the sub will enter an uncontrollable nose dive.

https://www.marineinsight.com/naval-architecture/understanding-stability-submarine/

 

Yes, would normally trim or balance out everything so nose is slightly upward. Gives some small leeway in an emergency, such as flooding or a loss of propulsion.

The presure is rather disturbing to contemplate when you start hearing the boat groaning or see doors swinging freely in their frames after having been compressed.

Considering the number of accidents of even military submarines over the years, the CEO was insanely reckless in regards to safety.

Edited July 10, 2023 by Endy0816

[Airbrush]

Was the Titan sub descending too fast?  Did anyone check out this Youtube transcript?  Authentic or fake?  Did they implode at about 9:47?  Was the crew in panic mode for about 20 minutes? 

According to the transcript, at 9:28 was the first alarm:

"We're noting an alarm from the rtm."

Last message from Titan at 9:46am:

"...reading red on the A power bus.  I switched to B. at 3457m more sounds aft"

 

 

Edited September 15, 2023 by Airbrush

[swansont]

Snopes concludes it’s a fake, so if that’s correct, this is moot

https://www.snopes.com/fact-check/titan-sub-transcript/

 

“Efficiency and brevity were a priority. There was absolutely no chitchat (such as "Enjoy the dive, gentlemen"). Often, the actual exchanges even omitted the verb, newspaper headline-style ("Bottom time up"), to save time and typing.”

Scroll to the end to see all of David Pogue’s analysis (correspondent who went on a dive, and so has first-hand knowledge)

[mistermack]

From what I remember, it does seem to be that they descended faster than standard. And they dropped the weights, and cradle, which should have got them rising at a good rate, but it only resulted in a very slow beginning of an ascent. 

It seems to me that they must have started taking on water early on, which would explain a faster descent and very slow beginning of ascent. They would have noticed if water was coming into the passenger part, but there was a separate chamber, so I think that began to fill on the way down, which they were unaware of. Nobody seemed to ask the question, why are we going down faster than usual? If they had done that, and aborted the dive, they would probably have survived.