Titanic tourist sub missing

[Checkmite]

Less black corn flakes than I was expecting.

It's a tiny model, so the carbon fiber strands are comparatively larger.

Certainly the implosion of a large carbon fiber hull like the Titan's would look different.

 

[Skeptical Greg]

.....so if they could rock the submersible enough, they would drop off.

Unbelievable, but believable in the context of the tragedy.

 

[SpuriusMaximus]

That's precisely why I DON'T think the ballast was intentionally released, and its being found separated was a result of the explosion instead. As I was saying, the interval from hull actually starting to delaminate and being picked by that acoustic monitoring and everyone being thin red paste, is less than the time needed from the signal from the eyes or ears to reach the brains. That they'd actually have time to literally rock the boat is IMHO... improbable.

Let me explain my reasoning some more: the whole 'safety' of the thing was akin to a holed condom. It just gives you a false sense of security when you're screwed

But give a false sense of security it does. Between the monitoring and that dissolving cord, you could sit there and think that nah, it's safe, the alarm didn't sound, until it was too late to do anything.

As evidenced by the fact that just that happened in 2022. The sub had to be taken out of commission and repaired after it. But that's the key word: "AFTER". They just sat through the whole thing even when the hull had started some (thankfully) minor delamination, thinking that it's safe. They did not rock the boat to abort. It tells you that things had to get REALLY critical for that.

 

[bruto]

Unbelievable, but believable in the context of the tragedy.

Could have been worse though. Next step was to get out and push.

 

[jeremyp]

Unbelievable, but believable in the context of the tragedy.

As I understand it, that was a deliberate design decision. It gives them a way to release the ballast without having any power.

 

[arthwollipot]

As I understand it, that was a deliberate design decision. It gives them a way to release the ballast without having any power.

But you've got to admit, it sounds janky as ****.

 

[jeremyp]

That's precisely why I DON'T think the ballast was intentionally released, and its being found separated was a result of the explosion instead. As I was saying, the interval from hull actually starting to delaminate and being picked by that acoustic monitoring and everyone being thin red paste, is less than the time needed from the signal from the eyes or ears to reach the brains. That they'd actually have time to literally rock the boat is IMHO... improbable.

Let me explain my reasoning some more: the whole 'safety' of the thing was akin to a holed condom. It just gives you a false sense of security when you're screwed

But give a false sense of security it does. Between the monitoring and that dissolving cord, you could sit there and think that nah, it's safe, the alarm didn't sound, until it was too late to do anything.

As evidenced by the fact that just that happened in 2022. The sub had to be taken out of commission and repaired after it. But that's the key word: "AFTER". They just sat through the whole thing even when the hull had started some (thankfully) minor delamination, thinking that it's safe. They did not rock the boat to abort. It tells you that things had to get REALLY critical for that.

My impression, from what Cameron says is that they believe that Titan had aborted the mission for reasons other than the location of the ballast. Perhaps the surface vessel got a message saying they were aborting. Even if I am wrong about that, they haven’t released the exact location of the ballast. Maybe it was a long way from the rest of the wreckage, too far to be explained by an explosion. Until we get all the details, your hypothesis is no more than a guess (as is mine).

Also, you would not normally have to rock the sub to abort. That’s only for the case where power has failed or the electrical mechanism failed. We don’t know if that happened in this case.

As for the acoustic warning system, I’d like more details about how it worked before declaring it would give them no time to react. Clearly it wasn’t good enough to save them but there’s a large gap between not enough time to save the crew and not enough time to react at all.

 

[SpuriusMaximus]

Well, it IS just a hypothesis. I'm just explaining what gives me that idea. Otherwise, yeah, your guess is as good as mine. In fact, probably better, if you're sober

 

[jeremyp]

But you've got to admit, it sounds janky as ****.

Well yes but can you think of a better method of releasing the ballast without using electrical power?

 

[arthwollipot]

Well yes but can you think of a better method of releasing the ballast without using electrical power?

I was going to say a simple lever and catch, but then I started thinking about how to get mechanical force from the inside of the pressure vessel to the outside of it, and I couldn't think of any that didn't introduce fatal weaknesses.

But you've got to admit, it still sounds janky as ****.

 

[MRC_Hans]

Some of the deep dive vessels have ballast held in place by electromagnets. If the power fails, it simply drops off.

Hans

 

[jeremyp]

Well, it IS just a hypothesis. I'm just explaining what gives me that idea. Otherwise, yeah, your guess is as good as mine. In fact, probably better, if you're sober

I am sober but I don’t think my guess is better than yours. In fact, the first draft of my reply included “we don’t know that the acoustic warning wouldn’t give them enough time to save the sub”.

That sentence is obvious bollocks. They’re all dead so the one indisputable fact is that they weren’t given enough time to save the sub.

 

[jeremyp]

Some of the deep dive vessels have ballast held in place by electromagnets. If the power fails, it simply drops off.

Hans

Yeah, that would be better.

 

[arthwollipot]

Some of the deep dive vessels have ballast held in place by electromagnets. If the power fails, it simply drops off.

I guess this is why I'm not a deep-sea engineer.

 

[erwinl]

I was going to say a simple lever and catch, but then I started thinking about how to get mechanical force from the inside of the pressure vessel to the outside of it, and I couldn't think of any that didn't introduce fatal weaknesses.

But you've got to admit, it still sounds janky as ****.

Neither can I.

I admit that it does give some credits to the concept of using a Bluetooth controller to control the machinery with. Thereby keeping the hull itself completely solid.
Now, the wisdom of using Bluetooth and a simple games controller is another question, but as a concept, I can see the possibilities.
Knowing the range and strength of Bluetooth, I suspect we have the reason for the carbon fiber hull here (or otherwise the Bluetooth was chosen after the design choice for the carbon fiber was made) as I don't think it will penetrate a solid metal hull.

Related question.
How do the other deep dive submersibles handle the question of the operator being inside, and the machinery they want to operate outside, without compromising their pressure hull?
Does anyone know?

 

[Andy_Ross]

As I understand it, that was a deliberate design decision. It gives them a way to release the ballast without having any power.

A correctly designed system would have released the ballast in case of power loss, the default power off condition should be the released one.

 

[Andy_Ross]

Well yes but can you think of a better method of releasing the ballast without using electrical power?

A big mechanical lever but as I already posted, the failsafe way to do it is to release the ballast if power goes off.

 

[Andy_Ross]

Some of the deep dive vessels have ballast held in place by electromagnets. If the power fails, it simply drops off.

Hans

That's the correct way to do it

 

[P.J. Denyer]

Neither can I.

I admit that it does give some credits to the concept of using a Bluetooth controller to control the machinery with. Thereby keeping the hull itself completely solid.
Now, the wisdom of using Bluetooth and a simple games controller is another question, but as a concept, I can see the possibilities.
Knowing the range and strength of Bluetooth, I suspect we have the reason for the carbon fiber hull here (or otherwise the Bluetooth was chosen after the design choice for the carbon fiber was made) as I don't think it will penetrate a solid metal hull.

Related question.
How do the other deep dive submersibles handle the question of the operator being inside, and the machinery they want to operate outside, without compromising their pressure hull?
Does anyone know?

That assumes that what the controller connects to is outside the hull which seems unlikely (especially given the monitors inside the cabin). I wonder what was running it? I'm thinking a Raspberry Pi!

 

[MRC_Hans]

Neither can I.

I admit that it does give some credits to the concept of using a Bluetooth controller to control the machinery with. Thereby keeping the hull itself completely solid.
Now, the wisdom of using Bluetooth and a simple games controller is another question, but as a concept, I can see the possibilities.
Knowing the range and strength of Bluetooth, I suspect we have the reason for the carbon fiber hull here (or otherwise the Bluetooth was chosen after the design choice for the carbon fiber was made) as I don't think it will penetrate a solid metal hull.

Related question.
How do the other deep dive submersibles handle the question of the operator being inside, and the machinery they want to operate outside, without compromising their pressure hull?
Does anyone know?

Well, I don't know how the Titan worked, but I know a bit about older types of deep-sea vessels.

Carbon fibre is at least partially conductive, so I doubt Bluetooth (which works in the microwave band) can penetrate it very well, if at all. It certainly can't penetrate metal, not even tin foil.

Lower wavelengths could probably go through the CF hull, such as the ones used in NFC.

In traditional bathyscaphes, where the hull is a metal sphere, all functions going through the hull, i.e. windows, hatches, wires, are essentially made in the same way: Cones. A suitable conical hole is made in the hull, and a conical glass pane (VERY thick), or hatch, or insulator with a centre wire, is fitted into the hole. There are of course seals or gaskets and retaining rings or opening mechanisms as appropriate, but what keeps the opening shut and water-tight is the pressure from outside. Thus, the pressure on, say, a window is transferred to the surrounding hull through the conical shape and balances the forces from the hull. So, if made right (there will be a bit of engineering to figure out the exact slope of the cone), the holes will not weaken the hull significantly.

Presumably, the window of the Titan was made in this way. This also explains why it was not present when the wreckage was recovered: It was simply blown outwards by the explosive phase of the implosion. ... And being made of acrylic, it was probably shattered.

Come to think of it: While the CF cylinder would be more or less conductive, it would probably be possible to apply a voltage between the end domes and thus have a way to pass a signal to the outside equipment. It would be a single channel, but you could probably pass an USB channel through that way. It would have a very low impedance, but that is only a question of a proper driver.

Hans