Tourist mini sub missing off titanic

[cockerpunk]

Originally Posted by Seahawk

That is what is most interesting to when combined with CP posts: how did they know, without multiple dives and post mission analysis then unmanned to failure with data capture, what was good versus bad noise emissions?

Happy to learn more.

because AE is an educated guess at what is happening AT BEST. thats why its not suitable for a safety system. AE monitoring of the cracking doesnt actually tell you how big they are, if they are clustered together, what is actually cracking, is this a continuation of a crack, or a new crack? the answer to any of of those questions dramatically determines the outcome from perfectly safe, to 'we didnt even have time to think about the AE and it killed us.'

[Seahawk]

Perfect. Thanks.

[Tobra]

Seems like the cracking would be carbon fibers breaking. Lots of noise on the first dive, less on each subsequent dive, until the last one

I still can't get past the epoxied butt joint holding it together

They fired all the old white guys that said it might not be safe

[cockerpunk]

Originally Posted by Tobra

Seems like the cracking would be carbon fibers breaking. Lots of noise on the first dive, less on each subsequent dive, until the last one

I still can't get past the epoxied butt joint holding it together

They fired all the old white guys that said it might not be safe

could be the fibers, could be the glue holding the fibers, could be the glue unsticking from the fibers, could be the glue holding on the end caps. could be a new crack, could be an old crack extending, could be a lot of things. using AE as a go-no go on safety is not a great idea because of this. you dont really know for sure what you are hearing in the material. some of these events might have tell-tale AE signatures, but most probably do not, and to find out for sure what those tell tale signatures sound like, you gotta crush a lot of stuff, very specifically, which its very clear they did not do.

[otto_kretschmer]

According to this program the Titan did 12 dives to the Titanic. Its possible the sub did more after this episode was filmed.

I can see how Rush got complacent. 12+ successful dives to 12000 ft. He did some destructive tests with a scale model so he thought he knew where the limit was.

[Jeff Hail]

Any new commercial or private adventures down to the bottom now have this stigma to deal with as well as what may be seen other than the main attraction. Very unfortunate event.

[Mahler9th]

Perhaps of interest:

https://www.nwyachting.com/oceangate-prepares-for-titanic-dive/

Ocean Industry

There are reports that they did a lot of testing and analysis.

Including unmanned submersions at great depths, instrumented with their hull monitoring system.

There are reports that a variety of labs were engaged to help them test.

There are reports that after one manned dive, they may have retired a capsule and did analysis which required destruction.

There are reports of at least one other sub made with CF that was developed over time by experienced people (at HOT) and that the Titan perhaps leveraged learnings from that effort as did apparently some of their subcontractors.

Much has been said about dissimilar materials, yet we know there are deep subs made from acrylic and at least one famous unit was made of ceramic.

And this famous sub was tube shaped and had ti end caps and metal flanges. And these were glued on. I provided some links to related technical info on this sub.

It imploded. Lots of info on that famous sub and its loss.

Depths greater than 4k feet I reckon.

I have not found any info on the Titan's hull monitoring system except what was published by a reporter at a link I provided previously-- an article by a reporter that interviewed Mr. Rush. Mr. Rush's description is far from a technical presentation, but it does suggest some thought was applied and testing was done.

I suspect that the hull monitoring system was protected by IP so perhaps there is some info in the public on that.

Perhaps in the literature as well, although I have not found any.

We may find out that the implosion had nothing to do with carbon fiber, ti flanges, hull monitoring, construction, porthole specs, et cetera.

We may find out that it was some typical item that is used in many subs.

Let's see what can be learned.

And yes, ventilators are very complex medical devices.

[Mahler9th]

Perhaps of interest:

https://www.researchgate.net/publication/235174559_Ceramic_External_Pressure_Housings_For_D eep_Sea_Vehicles

"Only glasses, ceramic and carbon fiber reinforced plastic can provide the necessary weight to strength ratio to make the external pressure housings for undersea vehicles positively buoyant at the abyssal design depth. This group of materials poses unique challenges to the designer and fabricator of pressure housings. This paper summarizes the findings of the R & D program aimed at developing the technology for the design, fabrication, and testing of ceramic housings culminating in the application of ceramic housings to the WHOI ROV/AUV diving system with 36,000 ft (11,000 m) capability (Figure 1)."

https://www.researchgate.net/publication/289330840_Operations_to_11000m_Nereus_ceramic_hous ing_design_and_analysis

[Mahler9th]

Ti end caps on ceramic tubes:

https://apps.dtic.mil/sti/citations/ADA273061

[otto_kretschmer]

Rush was a tinkerer. He should have just copied the Aluminaut, now on display at the Science Museum of Virginia in RIchmond.

https://en.wikipedia.org/wiki/Aluminaut

It can take 7 down to a test depth of 15k feet.

Proven technology from the 60s.

[URY914]

https://news.yahoo.com/pictured-first-fragments-destroyed-titan-151027948.html

[URY914]

https://news.yahoo.com/imploded-titanic-submarine-seen-first-144824288.html

[otto_kretschmer]

The titanium bits are intact. The carbon fiber hull is probably in fist size chunks on the bottom of the ocean.

[cockerpunk]

idk what he means by that evidence not showing it imploded violently.

looks like the carbon fiber hull imploded perfectly, and left everything else.

[otto_kretschmer]

Originally Posted by cockerpunk

idk what he means by that evidence not showing it imploded violently.

looks like the carbon fiber hull imploded perfectly, and left everything else.

It seems every youtuber and his mom is jumping on this story and most don't know anything about engineering.

This is a harsh lesson but avaition is full of bad designs, dead pilots and crashed planes. Anyone following Stockton Rush should stick with metallic hulls.

[David]

I modeled a 7' diameter, 5" wall thickness titanium sphere and a similar dimension rounded end tube to check stresses. I fixed a small spot on each and applied 5,500 psi pressure to simulate 12,500 ft depth. Note that sphere max Von Mises Stress is about 26 ksi while the tube max Von Mises Stress is about 43 ksi.

[GH85Carrera]

So the Titanic is in 12,600 feet of water. The water pressure is 5,878 Pounds per square inch!

So every single square inch has 5,878 pounds of pressure pushing on it. Wow.

Like climbing Mt. Everest, I just don't understand that drive in others. I do not think it should be regulated away. People will still sky dive, scuba dive and partake in very risky behaviors. The remains of the company will be sued into oblivion with only the lawyers winning.

It was likely an instant death. One moment they were happy and alive and then just gone in milliseconds.

[aschen]

its not impossible that memory cards in cell phones and data loggers would still have data. We have recovered flash memory data from flooded downhole tools exposed to in excess of 10ksi.

Semi conductors dont really have void space and have tiny effective areas, so counter intuitively they sometimes survive.

[dad911]

Originally Posted by GH85Carrera

....
It was likely an instant death. One moment they were happy and alive and then just gone in milliseconds.

One would hope, for their sake. I could also see a scenario where the CF was crackling and his hull monitors going off, but not enough time to climb.

I wonder if there was any sort of black-box/recording of the capsule......

[Baz]