Titanic submersible

It happened in international waters so its going to be a mess

Is the submersible registered anywhere? Is question 1

It might.
In my case it won't affect my decision at all.
There are pictures of the wreck available and my interest goes as far as looking at them, no more than that.

The naievety of breakfast TV presenters abounds again - today Ms Diamond was suggesting there should be a release button inside so they could all get out and float to the surface! Shame nobody thought of it

LOL that is funny. Bless their little hearts, gotta love the meeja. When I worked in the print publishing industry, the journalists were all equally oblivious to anything mechanical, or mathematical. They were all the kids at school who did well in English but failed to grasp percentages and fractions. Every year or so they seriously reported a local nutjob/conman who claimed he had made a machine that produced more electricity than it used and could thus be used to supply remote towns from a minimal supply. They religiously reported it as a scientific breakthrough every year -- as he announced he just needed a bit more financial backing from investors to market his machine. They could not be convinced it defied the laws of physics and continued to provide the charlatan with free publicity.

I don't think it is registered anywhere. Could not get certification. Legal action may end up in the USA where the company is based and lawyers are more abundant even than AR15s. Investigation is being run by the Canadian Transport Department and the US Coast Guard. They both have a dog in the fight as they provided most of the rescue support, at a cost of millions. Legalities may depend too on what country waivers and contracts were signed in etc. As you say, it will be messy.

Interesting reports keep referring to the US's "top secret listening device" that picked up the sound of an implosion on day one. Pretty sure that is defence-speak for a submarine. It is what they do. But you never give away their location. It is all smoke and mirrors with those guys.

More likely to be one of the chains of hydrophones the US has deployed in the Atlantic. It used to be called SOSUS (some detail in Wikipedia), but that (now declassified) technology will have ben superseded by something else.

On the disclaimer for "crew" vis "passengers" if this was a development or "test" dive there is a well established principle that the crew should only comprise those persons essential for the operation of the vehicle. People have been sanction in the UK at least for breaking this in aviation. It was tried by operators of vintage military aircraft. Thesr is now a route between vintage / military and commercial aircraft regultaion which has allowed the sale of flights in twin seat spitforws for example. I have been in the back of a twin seat spitfire over 25 years ago before this change but I was genuinely carrying out a flight test to investigate an unusual fault.

Robert

.

Perhaps she should be forced to watch this, to get a sense of proportion:

Edited By Michael Gilligan on 24/06/2023 12:03:32

Canadian investigation will be by the Transportation Safety Board Canada
https://www.tsb.gc.ca/eng/index.html
By international convention the resulting safety report cannot be used for litigation.
US investigation could be Coast Guard or / and NTSB. Coast Guard can be used for litigation NTSB not.

Robert.

mmm... I'm still wondering about this statement. Keeping it simple, if 'vacuuous' vessel under a hydrostatic pressure suddenly just disappeared, the velocity of the fluid would be zero at that time and point. It has mass, therefore it accelerates. It must be the fluid at the boundary of the collapsing cavity that has maximum velocity, as it has nothing to stop it. The velocity of the fluid crossing the original boundary line will drop off quite quickly due the diminishing flow-rate, as the cavity volume tends towards zero.

My thinking is that if this chap wanted a headline to give to the baying press, he would quote that of the 'final velocity' of the fluid at the very centre of the vessel/cavity, and not that of the fluid "entering the imploding vessel" (ie. crossing the original boundary), perhaps ?

......perhaps I'm getting a bit carried away. Its not as though I have nothing else to do. I think I still harbour a lingering irritation over those people that used to say, things like "if you don't wear a seatbelt you will hit the dashboard with the force of an elephant"

gerry

Yes that sounds about right. (Not the elephant bit!) Water at the periphery would start off at 0kmh and accelerate from there. Still, with 6,000psi behind it, it will not be hanging about. Until it hits the water coming in from the opposite side, with literally crushing results for anything in between.

Edited By Hopper on 24/06/2023 13:17:16

A simplistic alternative view … At the instant that the tube fails, a column of water [of whatever head is relevant] descends to fill the space. … There isn’t enough time for anything to significantly change shape.

MichaelG.

I think it might be more complicated than that though. A google search for "fluid dynamics of implosion" reveals a world of head-achingly complex books, PhD theses and theories, like THIS one. It seems it is not necessarily a certain thing and depends on many factors.

Intuitively though, I would expect water to rush in simultaneously from the sides and bottom, not just the column from above, because pressure is virtually the same all round. Close enough to make no difference.

This paper HERE raises several interesting points. One is the compressibility of seawater at that depth and pressure means the fluid will initially expand as it is exposed to the low pressure void in the collapsing vessel, presumably adding to the kinetic energy involved. This results in a low pressure in the surrounding water, followed by a spike as the water rushing in hits other water and comes to a stop. The other point is that a brittle material (eg carbon fibre) will make the shock of the implosion greater than if it is a more ductile material such as a metal.

Still no clue as to where the various professors are getting specific figures for the speed of the water in an implosion at that depth. I suppose they could apply the old F = M*A and calculate something over the 20 milliseconds of time for velocity. No idea how you would apply it in a fluid situation like this. Its way above my pay grade.

.

Excellent find, Hopper

I have downloaded the book, and will see how much/little of that paper I understand this evening

MichaelG.

Of course, I couldn’t resist having a quick skim through

Unfortunately although the relevance to deep sea exploration vehicles is mentioned, all of the reporting concerns experiments at much shallower depth.

I am, however taking the liberty of posting this one graph, which I think tells us a lot !

.

.

Whatever clever analysis we might hope to do, or see to be done by others … I think the X-axis pretty-much says it all.

MichaelG.

Another paper worth looking-at [free download]
Again, the scale of things is not representative of Titan

**LINK**

https://royalsocietypublishing.org/doi/10.1098/rspa.2013.0443?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed

MichaelG.

Hi, there is a lot of this above my pay grade, but of course the highest pressure is at the bottom of the water column, which many of us had probably been shown by the simple lab experiment at school Old School Experiment so I suppose the implosion could have started at the bottom of the tube, assuming that is what had failed, but of course the actual pressure difference between the bottom and the top of the sub, wouldn't have very much at that depth. Unlike a compressed gas, there isn't an equal pressure in all directions in a column of water. During some of my day jobs, I've been involved in lock gate and stop logs, and the hardest part to stop leakage is at the bottom of them. Below is a photo of one set of two that a workmate and myself, were contracted to install the frames and the logs, in a brand new eel pass on the River Dove, near Stoke-on-Trent. Being brand new, we didn't get any leakage problems thankfully.

Regards Nick.

Useful input, from a man who knows rather than just ponders !

“Unlike a compressed gas, there isn't an equal pressure in all directions in a column of water.”

… Thanks for sharing your practical experience, Nick

MichaelG.

Edited By Michael Gilligan on 24/06/2023 17:13:33

Hi, having a quick look through the book Hopper linked too, and seeing how those tubes have flattened out in Fig 18 section 4.2., in my old job, they had a submersible dewatering pump, which weighed about 3 Tonnes, and it would pump water for about two miles, however the 10" PVC pipeline was going uphill for a short distance before dipping slightly and then a very sallow downward long slope to the outlet, this was across a quarry, all was fine and dandy, but when the level of the water got low enough, the pump automatically cut out, which was fine. The problem was when it cut in again, and it pumped for a short while and then tripped several times for no apparent reason, the electrician was called to look at it but found no problems, so it was assumed that something had got into it and was causing to much of a back pressure. So to cut a long story short, we had to look inside the pipeline, and it turned out that where the pipeline reached the highest point, which was a little below ground level for about 20M back towards the pump, about 6M of the 10" PVC pipe had been suck as flat as those tube in Fig 18 mention above. No thought was given to allow air to be drawn back into the pipeline when the pump stopped during installation, I had no involvement in putting the pipeline in, I might add, as it was a contacted out job, but it does show the power of our meagre 14 psi of Air we live in, and a somewhat small amount of water running downhill.

Regards Nick.

Hi MichaelG, thanks for your vote of confidence.

Though it is surprising how many people you think ought to know these sort of things, actually don't.

Regards Nick.

The sum is easy. Using the incompressible Bernoulli equation (the second simplest equation used in fluid dynamincs), I can say without doubt that the water will have a velocity of 944 ft/s (1036 km/hr).

All you have to be is the professor of a university and the press will believe you.

Bernoulli is only relevant for steady flow.

JA

Edited By JA on 24/06/2023 18:09:05

Edited By JA on 24/06/2023 18:15:23