Missing Titanic tourist sub

[kerbiloid]

https://news.sky.com/story/submersible-debris-brought-ashore-after-deadly-implosion-12911152

[magnemoe]

1 hour ago, Nuke said:

while the gamepad memes are amusing, it didnt make the pressure hull implode. unless one of the tourists got mad and threw the controller at the inside of the tube. it would be amusing if they recovered it. 

It has two major issues, First is that the controller might be mission critical if you move toward the bottom or Titanic and it stop working , without secondary controls you will hit it and might get damaged or stuck.
its not designed for an marine environment.
But the worst part is wireless who makes it much less reliable. Now if it can work bout with  usb if plugged in or wireless if not, that makes perfect sense. 
 

[Nuke]

9 hours ago, magnemoe said:

It has two major issues, First is that the controller might be mission critical if you move toward the bottom or Titanic and it stop working , without secondary controls you will hit it and might get damaged or stuck.
its not designed for an marine environment.
But the worst part is wireless who makes it much less reliable. Now if it can work bout with  usb if plugged in or wireless if not, that makes perfect sense. 
 

not sure wireless is an issue, deep down where you have less ambient radio noise. most of the problems people have with wireless tech can be narrowed down to overuse of the frequency band in densely populated areas. wireless controls are most certain more reliable than wired ones (of course i have a cat that's a known cable chewer, so i might have a bit of a bias there), because it doesn't take much to mangle a usb cable.  worst you can do with a wireless controller is  interference, which probibly isn't very bad under 2.5 miles of seawater.

game controllers are pretty reliable though. and if you need redundancy, take two and never let the battery drop below 50%. keep a couple charging cables on board, and make sure the software on the device you plug it into has an alternative control method even if you have to turn thrusters on and off from the command line. you can have a vastly overengineered controller built into the sub and not get the same redundancy. 

it may also be non-stock. they could have disassembled it, gave the pcb a conformal coating to protect it from corrosion, replace the thumbstick modules for more robust industrial ones using hall sensors, hell they could have put it in an after market machined aluminum case, ive seen controller mods like that. im a hotas guy and would rather have a warbrd or warthog or some high end model stick hard mounted to the control panel with managed internal cabling. its sort of like how the rutan boomerang used a power mac as its avionics. its not production worthy but its fine for a one off. 

[Lisias]

22 hours ago, Nuke said:

game controllers are pretty reliable though. and if you need redundancy, take two and never let the battery drop below 50%. keep a couple charging cables on board, and make sure the software on the device you plug it into has an alternative control method even if you have to turn thrusters on and off from the command line. you can have a vastly overengineered controller built into the sub and not get the same redundancy. 

Reliable enough to be used by the Navy on their subs.

 

[razark]

48 minutes ago, Lisias said:

Reliable enough to be used by the Navy on their subs.

Something something lowest bidder.

[Lisias]

9 minutes ago, razark said:

Something something lowest bidder.

And, yet, they went there and back. In one piece.

[SunlitZelkova]

18 hours ago, Lisias said:

Reliable enough to be used by the Navy on their subs.

 

But not for controlling the actual sub itself. Although I will say the game controller is by no means the fatal design flaw of the thing.

[Lisias]

33 minutes ago, SunlitZelkova said:

But not for controlling the actual sub itself. Although I will say the game controller is by no means the fatal design flaw of the thing.

You see, nothing is so bad that can't go worse.

Army’s Laser Weapon Operated by XBOX Controller

https://warfarehistorynetwork.com/armys-laser-weapon-operated-by-xbox-controller/

And agreed, the Titan's problem was not the controller, it wasn't even technical. Apparently it was human - too few experienced engineers hired for the job, and the lead (apparently only?) engineer got itself caught into a self-confirmation bias without anyone to put him in check.

[SunlitZelkova]

1 hour ago, Lisias said:

And agreed, the Titan's problem was not the controller, it wasn't even technical. Apparently it was human - too few experienced engineers hired for the job, and the lead (apparently only?) engineer got itself caught into a self-confirmation bias without anyone to put him in check.

I would say it was technical- carbon fiber isn’t the best for submarines- but it was brought about by human error. The sub did just fine on previous times but it seems they kept using the same hull over and over again, and it degraded and went kablooey.

[lajoswinkler]

I don't really understand the engineering idea behind using carbon fiber for outside pressure.

Those fibers are strong for tensile stresses and make up excellent pressure vessels when the direction of winding criss-crosses (Titan's fibers were just wound like coil). However, they crumble upon compression, and they have different response to stress than epoxy, so it's certain that epoxy microfractures and fibers detaching from epoxy substrate will develop on cycling the stress.

To be blatanly honest, I think Oceangate is very much a form of cargo cult - fancy, modern, high technology material used for the sake of it, when it really was the thick epoxy resin that held against caving in, deteriorating more with each change of pressure.

Edited July 1, 2023 by lajoswinkler

[magnemoe]

31 minutes ago, lajoswinkler said:

I don't really understand the engineering idea behind using carbon fiber for outside pressure.

Those fibers are strong for tensile stresses and make up excellent pressure vessels when the direction of winding criss-crosses. However, they crumble upon compression, and they have different response to stress than epoxy, so it's certain that epoxy microfractures and fibers detaching from epoxy substrate will develop on cycling the stress.

To be blatanly honest, I think Oceangate is very much a form of cargo cult - fancy, modern, high technology material used for the sake of it, when it really was the thick epoxy resin that held against caving in, deteriorating more with each change of pressure.

Now  composite pressure vessels are used for helium in rockets and here we talk of hundreds of bars but as you say that is to prevent expanding who composites are much better at. 
But it should still have microfracture issues more so because cryogenic temperatures. 

Else I agree it was an stupid material to use, its not that weight is critical here.  As I understand the submarine was not an conversational submarine. It used weights, I assume they dropped one weight then the reached the bottom and the rest then they wanted to go up again. Sounds weird and cheap but it should be an very reliable system if designed correctly. 

[lajoswinkler]

1 hour ago, magnemoe said:

Now  composite pressure vessels are used for helium in rockets and here we talk of hundreds of bars but as you say that is to prevent expanding who composites are much better at. 
But it should still have microfracture issues more so because cryogenic temperatures. 

Else I agree it was an stupid material to use, its not that weight is critical here.  As I understand the submarine was not an conversational submarine. It used weights, I assume they dropped one weight then the reached the bottom and the rest then they wanted to go up again. Sounds weird and cheap but it should be an very reliable system if designed correctly. 

Allegedly, all ballast was dropped before it was crushed. The crew knew something was going wrong. We will never know what they exactly thought or how long it took from the initial alarms to aborting mission to crushing, but it is likely, even though they experienced no pain, they've died in some degree of fear. Owner was probably more aware of what was going on.

[kerbiloid]

1. Still no signs that the hull was a problem, rather than something insde.
If the ballast had been dropped, it's definitely not due to the hull leaks. This tells that the hull was intact.

2. If the craft is a technological prototype of a mass-produced deepwater submersible, the militaries would be ok with the risk, as it had performed several divings.
Especially, since the company is based in Everett, WA, at the navy base.
Something related to this, but made of cheap carbon snots.

So, not the hull is what to look at.
Probably, the hull was the most innocent part of that.

Something went wrong inside.

Edited July 1, 2023 by kerbiloid

[lajoswinkler]

31 minutes ago, kerbiloid said:

1. Still no signs that the hull was a problem, rather than something insde.
If the ballast had been dropped, it's definitely not due to the hull leaks. This tells that the hull was intact.

2. If the craft is a technological prototype of a mass-produced deepwater submersible, the militaries would be ok with the risk, as it had performed several divings.
Especially, since the company is based in Everett, WA, at the navy base.
Something related to this, but made of cheap carbon snots.

So, not the hull is what to look at.
Probably, the hull was the most innocent part of that.

Something went wrong inside.

It doesn't have to leak for the emergency to be high enough to drop the ballast. It's a composite material and will not suddenly cave in without any warning (the problem is that such warning would be perfectly useless since time until disaster is so short). Hull had sensors and I'm pretty sure there were several seconds between first alarm and ballast being dropped automatically or manually by the operator.

What could happen inside for the hull to be compromised?

[magnemoe]

1 hour ago, kerbiloid said:

1. Still no signs that the hull was a problem, rather than something insde.
If the ballast had been dropped, it's definitely not due to the hull leaks. This tells that the hull was intact.

2. If the craft is a technological prototype of a mass-produced deepwater submersible, the militaries would be ok with the risk, as it had performed several divings.
Especially, since the company is based in Everett, WA, at the navy base.
Something related to this, but made of cheap carbon snots.

So, not the hull is what to look at.
Probably, the hull was the most innocent part of that.

Something went wrong inside.

It was dropped say some minutes before implosion the crew might notice something is not right.  It could be sensors on the hull warning that something is wrong. 
Yes it could be something else like an unrelated electrical or communication fail. 

This was an commercial craft design to dive to shipwrecks at the ocean floor. Navy had nothing to do with it at all. 

And very little except the hull failing could cause it to implode. Yes it could impact something at speed but we know it was not the case. 
Worst case internal might be an fire, but that would run out of oxygen long before it could damage the hull. 
It could be the porthole, some reports say it was not rated for the depth and it was missing then they lifted it up, yes it could also be the water hammer after the implosion hitting it from inside there it is much weaker and can probably be popped out pretty easy. 

[kerbiloid]

1 hour ago, lajoswinkler said:

It doesn't have to leak for the emergency to be high enough to drop the ballast.

It does have a reason to do drop the ballast.
And as they have done it, the hull was definitely intact when they had noticed that something is not right.
So, the problem wasn't in the hull.

1 hour ago, lajoswinkler said:

What could happen inside for the hull to be compromised?

Probably something what affected its structural integrity. A hit, an explosion, a fire.

1 hour ago, magnemoe said:

It was dropped say some minutes before implosion the crew might notice something is not right.  It could be sensors on the hull warning that something is wrong. 

At the foursome Venusian pressure there are only two states of the hull: 1 and 0.
So, the ballast equipment was intact before the hull was crushed.

[lajoswinkler]

On 7/1/2023 at 7:39 PM, kerbiloid said:

It does have a reason to do drop the ballast.
And as they have done it, the hull was definitely intact when they had noticed that something is not right.
So, the problem wasn't in the hull.

Probably something what affected its structural integrity. A hit, an explosion, a fire.

At the foursome Venusian pressure there are only two states of the hull: 1 and 0.
So, the ballast equipment was intact before the hull was crushed.

There wasn't a jackhammer inside. Who would hit it so hard?

What is there to explode? Fire would be consumed very fast, way before affecting anything.

No, there is not just 1 and 0. It is a composite, heterogeneous material that had sensors inside, material prone to delamination, material that produced audible cracking on previous missions. This is not a homogeneous material that shows no signs of stress and suddenly gives in. Thick-walled, homogeneous, one-body steel spheres do not produce any sounds. Elasticity graphs for steel and composites are very different.

I am talking about seconds between alarms and implosions, not the scenario where the vessel is slowly squashed. It would be a fast, exponentially worse material tearing and then water hammer pulse.

[kerbiloid]

52 minutes ago, lajoswinkler said:

There wasn't a jackhammer inside. Who would hit it so hard?

A tiny piece of metal like a bolt, a nut, anything thrown enough fast, by a spring, a gas pressure, or else.

A battery.

52 minutes ago, lajoswinkler said:

What is there to explode?

From batteries to hydraulic and pneumatic cylinders.

***

Upd.

To continue the meme...

6 bar.

Spoiler

Edited July 2, 2023 by kerbiloid

[Meecrob]

55 minutes ago, kerbiloid said:

gas pressure

I think you are neglecting to consider the almost 6000psi outside the vessel. Lets pretend someone smuggled literal TNT aboard. According to :

https://www.sccm.org/getattachment/cc197ca2-fe84-47c0-b3ef-7d00abd6271b/Conventional-Explosions-and-Blast-Injuries

1 Kg of TNT produces an overpressure of 33.4psi, or in other words roughly 180Kg of TNT would need to be detonated to simply equal the outside pressure.

Now I realize my numbers are all rounded and I did not consider the distance of the hypothetical explosion to the hull wall, etc, but I feel confident to say that, for example, a battery exploding and tossing some shrapnel is not going through 5 inches of carbon fibre with 6000psi on the other side of it.

 

Edited July 2, 2023 by Meecrob

[kerbiloid]

1 minute ago, Meecrob said:

I think you are neglecting to consider the almost 6000psi outside the vessel. Lets pretend someone smuggled literal TNT aboard.

I'm not.

No need to exceed the pressure. It's enough to run a crack.

[Meecrob]

Carbon fibre does not crack the way you think it does. it de-laminates. As said above, it is a heterogeneous material.

[kerbiloid]

9 hours ago, Meecrob said:

Carbon fibre does not crack the way you think it does.

Carbon fibre is a envelope, attached to other structures, plastic, metal, glass,

[magnemoe]

On 7/2/2023 at 7:51 PM, lajoswinkler said:

There wasn't a jackhammer inside. Who would hit it so hard?

What is there to explode? Fire would be consumed very fast, way before affecting anything.

No, there is not just 1 and 0. It is a composite, heterogeneous material that had sensors inside, material prone to delamination, material that produced audible cracking on previous missions. This is not a homogeneous material that shows no signs of stress and suddenly gives in. Thick-walled, homogeneous, one-body steel spheres do not produce any sounds. Elasticity graphs for steel and composites are very different.

I am talking about seconds between alarms and implosions, not the scenario where the vessel is slowly squashed. It would be a fast, exponentially worse material tearing and then water hammer pulse.

Its an communication log going around, its not verified true but it describes that some of the hull integrity sensors went red that caused them to drop ballast, later they dropped the bottom frame who the had to struggle a bit to do. 
I say this sounds very plausible,
According to this log decent velocity was much faster than expected and accent velocity was low after dropping ballast. But none reacted that decent velocity was fast who is weird. 

[lajoswinkler]

1 hour ago, magnemoe said:

Its an communication log going around, its not verified true but it describes that some of the hull integrity sensors went red that caused them to drop ballast, later they dropped the bottom frame who the had to struggle a bit to do. 
I say this sounds very plausible,
According to this log decent velocity was much faster than expected and accent velocity was low after dropping ballast. But none reacted that decent velocity was fast who is weird. 

I've seen the alleged transcript. Some people on Youtube are already cashing in hard on the transcript analysis like vultures, it's disgusting.

I tend to lean towards it being fakery plopped by some weirdo. Nobody reacting to a very fast descent is highly implausible. We all know now that the company was stingy, but this is their boss in the submersible, one would think that such situation would provoke a reaction. Deducing from the fast descent and very slow ascent alone, one could easily reach the conclusion that the preparation was so poor because of poorly calculated buoyancy. That's below capabilities of average science fair students in elementary school. It's really leading us to such conclusion and that raises suspicion if you ask me. Too blatant, too obvious. That's why I think the transcript could be fake. The only other solution is that Oceangate is on the level of papier-mâché, crayons and plasticine...

Edited July 6, 2023 by lajoswinkler

[lajoswinkler]

On 7/3/2023 at 7:02 AM, kerbiloid said:

Carbon fibre is a envelope, attached to other structures, plastic, metal, glass,

No, it's not an envelope. It is the pressure vessel. 12.7 cm thick layer. Fiber "reinforces" epoxy resin. I've put reinforces in quotation marks because it played minor role in strengthening the structure against outside pressure, despite what Stockton Rush was saying. Thick epoxy resin was holding back bulk of the force.

I'm not sure what the envelope was. Perhaps a sheet of titanium wrapped around the cylindrical body, preventing seawater from touching it.

Edited July 6, 2023 by lajoswinkler