Tourist submersible visting the Titanic is missing 101

[JohnRBaker]

This is a developing story:

Titanic tourist submersible goes missing with search under way

https://www.bbc.com/news/world-us-canada-65953872

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[JStephen]

Wow.
Do they have sonar systems that can track it as it goes down, I wonder?

I recall reading long ago of the Trieste, "Nine metric tons (20,000 pounds) of magnetic iron pellets were placed on the craft as ballast, both to speed the descent and allow ascent since the extreme water pressures would not have permitted compressed air ballast-expulsion tanks to be used at great depths. This additional weight was held in place at the throats of two hopper-like ballast silos by electromagnets. In case of an electrical failure, the bathyscaphe would automatically rise to the surface." I wonder if the Titan has any similar fail-safe system?
What I find online describes the hull monitoring system (but unclear why that is even needed) but not a lot of detail otherwise.

 

[dik]

I would think that a problem at that depth would be pretty definitive...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[JStephen]

It occurs to me that a pinhole leak anywhere in that thing would be pretty much fatal. But any problem that wasn't instant should get some sort of distress call out, too.
They could potentially lose power or propulsion and be "okay" but stranded. From what I'm reading, they have enough supplies for 96 hours, and normally go down and back up in 8 or so.
I've read of them picking up underwater sounds when a sub imploded, but that was a much larger submarine presumably much shallower. But I would wonder if they didn't already have a pretty good idea of what went on down there.
Edit: Reading another article, they were planning to dive about 4:00 AM Sunday. And the Coast Guard is currently doing aircraft searches of the area, for whatever that implies.
Edit: They lost contact 1:45 into the dive. But this has happened before, also, the surface ship has to direct the sub to the Titanic wreck, and on one previous trip, they lost contact and therefore couldn't find the wreck. So potentially not as dire as it sounds.
Edit: A quote: "He added that because the passengers are sealed inside the vessel by bolts applied from the outside, 'there's no way to escape, even if you rise to the surface by yourself. You cannot get out of the sub without a crew on the outside letting you out.'"

 

[dik]

Youtube

https://www.youtube.com/watch?v=jyt7H2tF76w

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[ldeem]

When I read about the pressure hull construction (Ti end's with carbon fiber composite middle section) I had a gut reaction this is not a good idea. Two different materials, differing modulus of elasticity and thermal expansion coefficients would make for a very challenging analysis. Then considering using carbon fiber composite in compression application and finally the hull monitoring system.

Hopefully I am wrong about the pressure hull.

Some videos of the construction can be found here

https://youtu.be/WK99kBS1AfE

https://youtu.be/Vi4J1LDS504

 

[LittleInch]

Same thing will happen to one of those ultra space tourist vessels as well. Basically every flight / dive is a test flight / dive given the very few that they do.

Despite all the warnings I don't think they all really understood that.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[dik]

I suspect the sub's owner has already had their legal department review the contract with the passengers.

Can a large electromagnet (with a long cable) be used to retrieve the sub, if they find it?

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[thebard3]

If this thing sank, it's likely to be an enduring mystery as it's almost certain to never be found. If it didn't sink, and is bobbing around out there somewhere, then the occupants will be trapped until it is found and opened from the outside. I believe in either case, it should have some kind of autonomous locators that function regardless of the condition of the vessel.
I'm just conjecturing and opining here. Perhaps someone with firsthand knowledge can pipe in.

Brad Waybright

The more you know, the more you know you don't know.

 

[JStephen]

On the electromagnet- the sub is carbon fiber and titanium. But I gather that it does have drop weights, and if not entangled or collapsed, should have bobbed to the surface by now.
There's all kinds of things that could be done with sufficient time. But they can't hardly get equipment to the site to start looking within the 96 hour time-frame. So if they're not found on the surface, they're probably not going to make it.

 

[dik]

Thanks... didn't know that it was substantially non-magnetic. If located, it may be difficult to connect to it.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[btrueblood]

The design engineer listed on their website is no longer employed?

 

[dik]

That may say something about the company, too.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[dragon6172]

I suspect the sub's owner has already had their legal department review the contract with the passengers.

The CEO is onboard the missing sub. Just like the Captain of the Titanic, it seems he will have gone down with his ship.

 

[Cool_Controls]

I watched the video of oceangate gluing the titanium ring to the carbon fiber tube, I know structural adhesives are a thing and this joint should always by under compression, but it still gives me the willies. Does anyone know how a connection like that could be inspected or monitored?

 

[Murph 9000]

If this thing sank, it's likely to be an enduring mystery as it's almost certain to never be found. If it didn't sink, and is bobbing around out there somewhere, then the occupants will be trapped until it is found and opened from the outside. I believe in either case, it should have some kind of autonomous locators that function regardless of the condition of the vessel.
I'm just conjecturing and opining here. Perhaps someone with firsthand knowledge can pipe in.

The US Navy has a ship which could very likely find it if it's on the bottom, RV Petrel. Unfortunately, RV Petrel is currently laid up in Leith, Edinburgh, Scotland; with some damage after it recently fell over in dry dock. Petrel can operate beyond 4000m depth and would have a decent chance of locating it if USN were willing to allocate the resources for the search. I don't know the current status of the repairs to Petrel, but it could be many months before she can even leave Scotland. Petrel is the ship which located and surveyed the USS Indianapolis at 5500m, operated by Paul Allen's ocean research organisation at the time.

The Royal Navy also have RFA Proteus which is similar to RV Petrel. It's also currently laid up in dry dock, undergoing conversion and refit. Even if Petrel, Proteus, or a similar deep ocean research/surveillance vessel were on site today, that type of search could take a very long time to locate it on the bottom; the chances of finding it within the 96 hour window would be small.

If it's on the surface, there's a decent chance it will be located within the small time window where rescue would be possible. The weather and sea conditions sound like they are reasonable, and that type of maritime search and rescue is something which is well practiced and it's feasible to get a lot of resources into the area quickly.

As far as locators go, underwater is not so easy. On the surface, the standard would be an EPIRB, but normal commercial EPIRBs probably would not be able to handle the 400 bar pressure they would experience if externally mounted at 4000m depth. If it was on the surface and had a functioning EPIRB, this story would already be over; that scenario is pretty much a guaranteed rescue within about 12 hours.

 

[Cool_Controls]

Does anyone know if the submarine operated with a high oxygen environment? Heck even a simple lithium battery fire in a space that small could be deadly.

 

[dik]

Thanks, dragon... their board is likely reviewing the contracts.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Cool_Controls]

I`m sure they are reviewing the refund verbage.

 

[thebard3]

if USN were willing to allocate the resources for the search

I don't know who would pony up the cash to look for it. Also, It's doubtful to even be in the immediate vicinity of the Titanic, or it could be right on top. Who knows? If it's not, then due to it's small size, would be kinda like looking for a piece of a needle in a haystack.

Brad Waybright

The more you know, the more you know you don't know.