Based on this it seems pretty likely that it immediately imploded and the ‘banging’ was from the Titanic debris itself.
Though they could not confirm that it was really the sub (they probably thought that it was, but they can't officially say it).
The latter is more probable to me as it has never been tested under water for more than a few hours at a stretch.
This will also be consistent with your banging hypothesis which was only heard after a day or two when it got lost. And also with the fact that no immediate sound disturbance was registered with the controlling ship.
I of course would very much hope it imploded way before any psychological trauma was inflected on the passengers, but sadly I think the most consistent hypothesis with the little data we have is that it got lost and went astray for around two days then imploded.
They got lucky with that until they didn’t.
They even fired a guy for whistle blowing about the porthole.
It’s a shitshow from start to finish.
The filing states that OceanGate refused to pay for the manufacturer to build
a viewport that would meet the Titan’s intended depth of 4,000 meters. The
Titanic lies about 3,800 meters below the surface.
The filing also claims that hazardous flammable materials were being used
within the submersible."It imploded later" requires at least two failures, first of power/comms, and THEN of the structure itself.
Occam's Razor
It imploded later requires only one failure (the structural failure), just as the relatively short time duration option requires only one failure. Right away is also a later event.
We have no way of knowing what its structural true condition was in terms of whether it was more likely to make it a very short duration or something more like a day.
is only good as a heuristic for finding which hypothesis to test first.
It's basically a scientist's "where there's smoke there's fire".
Wouldn't an implosion be really loud?
"Lost then imploded" explains both by adding only a small extra assumption so by occam's razor is strictly superior to imploded straightaway as far as I can see.
My money is on simple catastrophic failure of the hull and it not being detected either because the private company is run by jokers who weren't listening for it or because they have been running around like chickens with their heads cut off because the CEO and paying customers just died and they don't want to have to report that to the family, government, media, insurance company, etc... Either explanation is plausible, but I'm slightly more inclined to go with the second simply because they were actively trying to communicate with the sub when it happened and it seems so improbable that they could miss it.
As for the banging sounds heard days later, there are a thousand possible sources of those, especially with a dozen or more other vessels on the scene. Anything from a buoy with a loose part clanking away, to some waves breaking and clapping on the surface, to a whale slapping its tail, to extraneous noise from one of the search vessels or its equipment, to other sources of sea life making a racket. It's a bit like trying to listen for the buzzing of a bee in a basketball stadium with a game going on. Any signal you get is far more likely to be something else, but when you have literally no better options, every signal, no matter how unlikely, is worth investigating. Then they report they investigated and found nothing, and in a bit of target fixation, people assume it must have been people in the sub. Understandable, but it's not necessarily the most likely/logical conclusion.
> The latter is more probable to me as it has never been tested under water for more than a few hours at a stretch.
That's not true, they've successfully reached the Titanic several times over a dozen or so expeditions. Mike Reiss (a famous writer for The Simpsons) said his trip reached the Titanic but got lost for most of the ~8 hour trip, but that another group on his trip had several hours to explore the Titanic.
is there more information on these dissolvable ties? or their redundant ballast systems?
https://unsungscience.com/news/back-to-titanic-part-1/
Excerpt from the transcript:
But what if the hydraulic system breaks? Well, then they have roll weights.
KYLE: Ah, so, we’ve got these weights here on the side, these are roll weights, we can actually roll the sub and those come off, and that gains us some buoyancy to come back to the surface.
These are pipes that sit on a shelf that juts out from either side of the sub, held in place only by gravity. If everyone inside the sub shifts their weight to one side, the sub tips enough to let these pipes roll off.
If that doesn’t work, there are ballast bags, full of metal shot, hanging below the sub.
KYLE: These bags down below, we drop those off using motors and electric fingers.
OK. But what if the electronics go out, and the hydraulics fail, and everyone inside has passed out unconscious?
KYLE: There’s fusible links within these that actually can dissolve and come back in time if it’s drop off.
Fusible links are self-dissolving bonds. After 16 hours in seawater, those bonds disintegrate, the weight bags drop off automatically, and you go back to the surface.
You'd think - but past passengers have said that when they dove they lost contact as well.
Mutiple trip passengers said they lost contact every time.
So multiple anecdotes of loss of contact with the same vehicle without an implosion. The jankiness of this operation continues to be discovered bit by bit.
ETA:
https://abcnews.go.com/US/former-titanic-submersible-passeng...
David Pogue seems to concur with this [1]. He saw them lose track of where the sub was located (wrt to the Titanic wreck), but he said the support ship never lost the ability to communicate with the sub.
[0] https://bleav.com/shows/what-am-i-doing-here-with-mike-reiss...
That indicates a certain blase, routine attitude to communication loss.
This is more concerning, given that metal fatigue is an understood phenomenon (1).
(1) https://www.faa.gov/lessons_learned/transport_airplane/accid...
...With titanium hemispheres at each end, so some sort of poorly understood titanium carbon-fibre interface.
That would mean it had two mostly independent failures (which is less likely than one).
The only way it wouldn't have already surfaced on day 1 is if it got stuck on something (and lost power, unlikely), or it imploded.
https://community.sw.siemens.com/s/article/what-is-a-sn-curv...
If the were too cheap to design and build it properly then they were too cheap to check for wear and tear properly.
A sub is subjected to static stress mostly. Quite a lot actually at these depths. And having it certified for 1.3 km hints to over stressing.
As was pointed out, the submersible is pretty large and its a essentially a large cylinder which induces stress in the middle. Usually you make deep sea submersibles out of a sphere or spheroid because you don't have this failure modes.
It isn't surprising it failed. They were strong claims that the company did do enough test, rejected safety advice and even had the CEO claim that at one point the titan wouldn't be able to reach the titanic because it (a model maybe?) had experience a pressurization failure. To say nothing of the materials they were using.
Just comically bizarre that anyone involved in the project thought it would somehow survive let alone be safe.
So saying it got lost and imploded after a few days solves two problems. Explains why there was no implosion noise originally, and that the banging heard afterwards was the implosion. Also it has a history of losing contact in its previous tours.
Why would they be listening? They would be looking at a device that was communicating via SMS or some radar screen at best.
> and that the banging heard afterwards was the implosion
Every 30 min?
We don't know that. There's a chance a noise was recorded but it wasn't made public in order not to compromise rescue attempts.
Weren't there a lot of boats and other resources listening once it was reported missing?
It's one thing for the tender to not hear an implosion when no one else was following this excursion. It seems harder to explain no one hearing an implosion when a growing number of resources were trying to detect any signs of activity from the sub.