OceanGate Submersible Goes Missing During Titanic Dive

[toucana]

n 2022 the BBC filmed inside the OceanGate Titanic submersible that has now gone missing during a dive to see the wreck of the Titanic, which lies on the seafloor about 12,500 feet below the surface, and around 370 miles off the coast of Newfoundland.

https://www.bbc.co.uk/news/av/world-us-canada-65958697

In the screenshot below, Stockton Rush the Chief Executive of OceanGate who is believed to be one of five people missing aboard the submersible is seen explaining how it works

“It’s got one button, and that’s it. We run the sub with this game controller - It’s made by Logitec, but it’s basically a Sony PS style controller”  he says  -

What could possibly go wrong ?

Edited June 20, 2023 by toucana
typo 'submersible'

[swansont]

3 hours ago, toucana said:

What could possibly go wrong ?

I know this is probably rhetorical, but we can’t know, without more detail.

A properly-designed submersible would likely have a way to surface that didn’t rely on the main control. Maybe it did, but there was a leak that couldn’t be overcome by the ballast tanks. Maybe orcas got them.

[Bufofrog]

As an ex submariner this skeezes me out... Yuck.

[toucana]

59 minutes ago, swansont said:

I know this is probably rhetorical, but we can’t know, without more detail.

A properly-designed submersible would likely have a way to surface that didn’t rely on the main control. Maybe it did, but there was a leak that couldn’t be overcome by the ballast tanks. Maybe orcas got them.

I've read elsewhere on the BBC website that a submersible of this type would normally have a hydraulically operated ballast-release system that jettisons several hundred Kilos of metal to restore positive buoyancy, and allow the vessel to float back to the surface.

The hydrostatic pressure at this depth (2.3 miles underwater) is around 25,000 PSI -  far beyond the 'crush depth' threshold for any normal pressure-hull submarine - so any leak would have been instantaneously terminal.

[swansont]

According to a CBS story about the sub you have to sign a waiver acknowledging that the sub is experimental and not certified by any regulatory agency before you go on the dive.

part of that vid is embedded in a twitter post here

https://www.yahoo.com/entertainment/cbs-story-oceangate-missing-titanic-125815139.html

[toucana]

US court filings disclose that OceanGate fired a whistleblower in 2018 who raised concerns about the safety of the glass viewing port in the submersible that has now gone missing.

https://newrepublic.com/post/173802/missing-titanic-sub-faced-lawsuit-depths-safely-travel-oceangate

David Lochridge who was the director of marine operations, and was responsible for the safety of all crew and clients, had voiced a number of concerns about the safety of the submersible. He was particularly concerned that the manufacturers of the glass viewing port would only certify its safety to a depth of 1300m (The Titanic lies nearly 4000m below the surface on the seabed).

The submersible was built as a cylinder of 5” thick carbon fibre with Titanium end-caps. David Lochridge had refused to green-light manned tests of the submersible until further NDT engineering studies had been carried out into the effects of pressure cycling on the hull and window seals at extreme depths.

"Lochridge learned that the viewport manufacturer would only certify to a depth of 1,300 meters due to experimental design of the viewport supplied by OceanGate, which was out of the Pressure Vessels for Human Occupancy (“PVHO”) standards. OceanGate refused to pay for the manufacturer to build a viewport that would meet the required depth of 4,000 meters."

The submersible lost contact quite abruptly around 1h 45m into a planned 2h descent to the sea floor.

[exchemist]

3 hours ago, toucana said:

US court filings disclose that OceanGate fired a whistleblower in 2018 who raised concerns about the safety of the glass viewing port in the submersible that has now gone missing.

https://newrepublic.com/post/173802/missing-titanic-sub-faced-lawsuit-depths-safely-travel-oceangate

David Lochridge who was the director of marine operations, and was responsible for the safety of all crew and clients, had voiced a number of concerns about the safety of the submersible. He was particularly concerned that the manufacturers of the glass viewing port would only certify its safety to a depth of 1300m (The Titanic lies nearly 4000m below the surface on the seabed).

The submersible was built as a cylinder of 5” thick carbon fibre with Titanium end-caps. David Lochridge had refused to green-light manned tests of the submersible until further NDT engineering studies had been carried out into the effects of pressure cycling on the hull and window seals at extreme depths.

"Lochridge learned that the viewport manufacturer would only certify to a depth of 1,300 meters due to experimental design of the viewport supplied by OceanGate, which was out of the Pressure Vessels for Human Occupancy (“PVHO”) standards. OceanGate refused to pay for the manufacturer to build a viewport that would meet the required depth of 4,000 meters."

The submersible lost contact quite abruptly around 1h 45m into a planned 2h descent to the sea floor.

What "contact" was lost? I thought radio didn't work under water. 

[Externet]

The "contact" communication with a submarine can be conducted in ultrasonics, ultra low radio frequencies, optical methods.  Radio waves are severely attenuated in seawater. ☹️

Tridimensional directional sensing/finding at long ranges is not simply achieved, worsened by noise floor levels and interference masking signals.   Side-scan sonar is very limited in range to conduct a search.

Edited June 21, 2023 by Externet

[geordief]

58 minutes ago, Externet said:

The "contact" communication with a submarine can be conducted in ultrasonics, ultra low radio frequencies, optical methods.  Radio waves are severely attenuated in seawater. ☹️

Tridimensional directional sensing/finding at long ranges is not simply achieved, worsened by noise floor levels and interference masking signals.   Side-scan sonar is very limited in range to conduct a search.

Could they have attached one or two "echo locator" devices on the side of the Titanic before they paid it any visits ?

It would send reports to the surface every few hours.

 

Would it be able to scan the area on a continuous  basis  and be useful in this sort of a need.

 

At that range would it have  a directional ability?

[swansont]

They’re picking up banging sounds

https://www.cnn.com/americas/live-news/titanic-missing-sub-oceangate-06-21-23/index.html

[Externet]

57 minutes ago, geordief said:

Could they have attached one or two "echo locator" devices on the side of the Titanic before they paid it any visits ?

It would send reports to the surface every few hours.

 

Would it be able to scan the area on a continuous  basis  and be useful in this sort of a need.

 

At that range would it have  a directional ability?

Unsure if you mean echo locator as a ping beacon, or a 'repeater' attached to the Titanic that picks up nearby? submarine noises/com and relays in higher power to surface/distant receiver.

If a locating/searching receiver is at surface -say 5Km- from a beacon in the lost submersible,  to triangulate in 3D the arriving timing shifts of a signal to find its source, I have to assume it would take synchronized time receivers hundreds of metres or Kms apart to measure and compute direction for the 1500m/s acoustical propagation signal.  And that is if they are not moving by currents/tumbling by the seafloor.  Sea is not water at rest.

If by magic they had an extra week or even a month of air supply, they would still be doomed, no food, no heating, no drinking water, probably no light in board. 🥵

Edited June 21, 2023 by Externet

[TheVat]

I've wondered if the ballast release mechanism jammed.  Otherwise  seems like they would have popped up like a cork by now.  If they can home in on the banging, how would they get a cable down there and hooked on to winch it up?  Some kind of waldo/robot?  

I thought most deep ocean submersibles had a safety tether attached when they dove, but apparently this one didn't.

On 6/20/2023 at 8:42 AM, swansont said:

Maybe orcas got them.

They say aging billionaires are tender and delicious.  

Edited June 21, 2023 by TheVat
tether question

[mistermack]

4 hours ago, exchemist said:

US court filings disclose that OceanGate fired a whistleblower in 2018 who raised concerns about the safety of the glass

I think this is going to become known as OceanGategate. 

My initial reaction was that if they are not back on the surface after a few hours from losing contact, then they are done for. I can't imagine that they would continue on, having lost contact, so they should have been on their way back up after 1.5 hours or so. The fact that it didn't happen must mean that they can't surface, even in emergency conditions. It's sad but nearly hopeless, I think. I'd like to be wrong though.

[exchemist]

30 minutes ago, mistermack said:

I think this is going to become known as OceanGategate. 

My initial reaction was that if they are not back on the surface after a few hours from losing contact, then they are done for. I can't imagine that they would continue on, having lost contact, so they should have been on their way back up after 1.5 hours or so. The fact that it didn't happen must mean that they can't surface, even in emergency conditions. It's sad but nearly hopeless, I think. I'd like to be wrong though.

But what I want to understand is how can they “lose contact” when that’s what happens anyway as soon as they submerge?

[Genady]

10 minutes ago, exchemist said:

But what I want to understand is how can they “lose contact” when that’s what happens anyway as soon as they submerge?

This is what I've found so far on this question:

Quote

The Titan would have had an acoustic link with its surface vessel, set up through a transponder (a device for receiving a sonar signal) on its end, and a transceiver (a device that can both transmit and receive communications) on the surface vessel.

This link allows for underwater acoustic positioning, as well as for short text messages to be sent back and forth to the surface vessel - but the amount of data that can be shared is limited and usually includes basic telemetry and status information.

(What are submersibles, how do they communicate? (rte.ie))

[exchemist]

20 minutes ago, Genady said:

This is what I've found so far on this question:

(What are submersibles, how do they communicate? (rte.ie))

Ah I see. So sonar can be used to transmit text. Interesting.

[mistermack]

If I was designing it, I would like to have a fibre optic cable running from mother ship to sub. The stuff is everywhere these days, so it's hardly a hard-to-source new-fangled idea. Apparently, losing contact was a fairly regular occurrence. Personally, I wouldn't tolerate that situation if I was running the show.

Contact was lost after 1hr45m so it's not likely that they were fully descended at that point. (I'm guessing). If the rule was to abandon the dive and re-surface on loss of contact, they would have been back on top within an hour or two. 

[swansont]

3 hours ago, TheVat said:

They say aging billionaires are tender and delicious

They’re like veal.

3 hours ago, TheVat said:

I've wondered if the ballast release mechanism jammed. 

There are multiple mechanisms, according to one story I ran across. The main one is apparently release of weights by tipping the submersible to some angle (everyone gets on the same side and it lists)

[TheVat]

1 hour ago, mistermack said:

If I was designing it, I would like to have a fibre optic cable running from mother ship to sub. The stuff is everywhere these days, so it's hardly a hard-to-source new-fangled idea. Apparently, losing contact was a fairly regular occurrence. Personally, I wouldn't tolerate that situation if I was running the show.

Contact was lost after 1hr45m so it's not likely that they were fully descended at that point. (I'm guessing). If the rule was to abandon the dive and re-surface on loss of contact, they would have been back on top within an hour or two. 

From what I've read about submersibles, many do have some kind of tether to a surface support vessel, with a comlink and a physical support.   But high tensile strength tethers have quite a bit of weight especially as depths go to Titanic depth, and many ships can't handle them.  But a lighter weight FO cable seems manageable, and more affordable.  

[swansont]

7 minutes ago, TheVat said:

From what I've read about submersibles, many do have some kind of tether to a surface support vessel, with a comlink and a physical support.   But high tensile strength tethers have quite a bit of weight especially as depths go to Titanic depth, and many ships can't handle them.  But a lighter weight FO cable seems manageable, and more affordable.  

You’d have to unspool it fast enough that there’s slack, but not so fast it tangles up. And the connection (and fiber) has to be strong enough to pull the rest of the cable. Not sure you can do that with a >4 km cable.

[TheVat]

3 minutes ago, swansont said:

You’d have to unspool it fast enough that there’s slack, but not so fast it tangles up. And the connection (and fiber) has to be strong enough to pull the rest of the cable. Not sure you can do that with a >4 km cable.

Ok, I see the problem,  thanks.  Crossing trips to the Marianas Trench and the Titanic off my bucket list.  

[mistermack]

I suppose you could design some floats to be deployed at intervals along the cable, to neutralise the weight of the cable. The ones near the bottom would have to be pretty rigid, to take the pressure, but if the sub can take it, then a rigid sphere of carbon could too. 

[swansont]

1 hour ago, mistermack said:

I suppose you could design some floats to be deployed at intervals along the cable, to neutralise the weight of the cable. The ones near the bottom would have to be pretty rigid, to take the pressure, but if the sub can take it, then a rigid sphere of carbon could too. 

Winding and unwinding becomes far more difficult if you add other shapes, and now the cable connection has to pull even more mass, which is less streamlined , so there’s even more resistance.

On 6/20/2023 at 6:53 AM, toucana said:

“It’s got one button, and that’s it. We run the sub with this game controller - It’s made by Logitec, but it’s basically a Sony PS style controller”  he says

Not uncommon in the military. 

https://arstechnica.com/gaming/2023/06/missing-titanic-sub-isnt-the-first-to-use-game-controls-for-heavy-machinery/

There was a story a while back about the US navy designing a controller (I think it was for periscopes) that was clunky. The off-the-shelf solution worked much better.

edit:

https://www.geekwire.com/2017/u-s-navy-swapping-38000-periscope-joysticks-30-xbox-controllers-high-tech-submarines/

[mistermack]

It might be that standard fibre optic cabel simply wouldn't function at deep ocean pressures. It might get crushed so much that signals get blocked. I don't know what kind of cables are used to cross the oceans, but if they just lie static on the ocean bed, then weight wouldn't be so much of a factor, so they can be designed to be more robust and pressure resistant. 

Maybe you would need a special fibre-optics, that have water rather than air in the tube, so that pressures would not be a factor.

In the ocean, the weight of the cable would be supported by the water, so that the weight that needs supporting would be the difference between the weight of cable, and the weight of water it displaces. With a bit of work, you could come up with a cable of neutral bouyancy that could withstand enormous pressures. 

Of course, what's possible is not likely to be financially viable. It's a very limited market.

[Genady]

The submersible is either on the surface or on the bottom. If it is on the bottom, it will perhaps never be found. The search efforts will quickly stop after the rescue will turn to recovery. (MHO.)