Oceangate-gate....

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I'm seeing elsewhere that the Boeing 787 contains about 20 to 23 tons of carbon fiber, about twice the total mass (including titanium bulkheads and iron ballast) of Titan. Though much of that is in CF-reinforced composites, totaling up to even more mass.

It looks like Titan had a CF cylinder inside diameter of 56", so the outside would have been about 66". The 787 fuselage appears to be about 227" in diameter, though I'm not sure it is quite cylindrical.

 

I'm a few days late for most of this, but a couple comments...

1. Redundant surfacing mechanisms: Wouldn't have mattered in this case. When the pressure vessel failed, they were dead within 50 milliseconds. Not only were they crushed to nothingness(imagine the weight of one elephant per square inch), but they were incinerated at the same time by the heat of the implosion. Only after both of those, came the rebound explosion that scattered the remaining debris. Searching for a positive, it takes at least 100-500 milliseconds for the brain to register pain, so they literally didn't feel a thing.

2. de Havilland Comet: Contrary to popular belief, the square windows were not the primary cause of the Comet's issues. They weren't even a secondary cause. Heck, they weren't even square. Much of the square window myth came from news agencies misunderstanding the official reports. One of the real primary failure points for the Comets were a pair of cutouts on the top of the plane for the ADF antennas. In the report, these were referred to as the "ADF Aerial Windows". It's likely the press saw this and misunderstood what was meant. While the cracks did promulgate through the cabin windows, they didn't originate there. Mentour Pilot on YouTube did a great deep dive on the Comet misunderstanding not too long ago on his second channel, Mentour Now!.

 

Did that submersible even have any penetrations of the pressure hull, apart from the front window? After all the corner-cutting I've read thus far, I'm ready to believe that the submersible had two air-gapped technical systems: one inside the hull and another one outside it, communicating via $3 bluetooth dongle.

"See! We are geniuses! we eliminated all those pesky potential leaks! Now could somebody out there enter pairing code 84423 so we can surface?"

 

I'm keeping an open mind about this but agree its material characteristics remain an excellent research subject. One approach I'd heard about is to mix fibers with molten metal. The carbon fiber does not have to be held together with a polymer. For those worried about compression failure, the tensile strength of fibers can inhibit the deformation of impending compression displacement.

Bob Wilson

 

Yes, metal matrix composites use metal instead of resin.

https://en.m.wikipedia.org/wiki/Metal_matrix_composite

Posted via the PriusChat mobile app.

 

This likely won't play well in a courtroom:

"Over cigars one night, Rush told Weissmann that he got the carbon fiber for the Titan’s hull at a big discount because it was past its shelf-life for use in airplanes, Weissmann said. But Rush reassured him it was safe."

Local TV version: Previous passengers recall ill-fated Titan ...

AP version: Previous Titan passengers recall ill-fated submersible: 'I 100% knew this was going to happen' | AP News

Similar stories elsewhere indicate that it was scrapped from Boeing.

 

Don't ignore fatigue failure. This sub had made multiple trips to extreme depth and the pressure cycles likely had weakened the hull.

https://qr.ae/pyM2ZN

JeffD

 

I watched a YouTube video about the construction and it showed a linear wrap, not a cross weave wrap used for pressure vessels. One of my early mechanical engineering courses explained that a surface under stress, the force, exhibits a stronger strain at 45 degrees.

There may have been other failure modes but there really needs to be a debris analysis. I look forward to one or more crash safety groups final report.

Bob Wilson

 

De Havilland pioneered the pressurized cabin jet airliner. Boeing learned from De Havilland's mistakes and developed the 707. The revised Comet was totally safe but could not compete with the 707. For many years, it was employed by the Royal Air Force as in the AWACS role as the Nimrod. The were retired and replaced i the 2010's.

Twenty years earlier Boeing introduced the 247 and would not sell it to TWA. who commissioned Donald Douglas to eventually produce tle legendary DC 3, many of which are still flying today.

It's not always best to be the first.

 

111 years with no deaths? pretty good record

 

I suppose it is the most visited deep ocean site.

 

Beebe Bathysphere seems to have begun non-military deep (>1000 m) ocean exploration in 1934. One could start with that. Add up all the person hours since, with no fatalities (I guess there were not) since. Until Stockton and friends got their final rush.

What other wild explorations had that many initial person hours with no fatalities? Certainly not powered flight. This would be a basis for quantitative comparison. @bisco's claim was not such. Not to me. Hint was he said "pretty good" a phrase not typically used in quantitation.

 

Deep sea tourism can possibly exist and expand, but safety can never be second to economics. Aviation already proved this.

Stockton Rush, other than being a great name for a California AAA baseball team or maybe a particular batch of crystal meth, used an approach that was Lawnchair Larry-as-a-Service. Not even worth comparing to honest attempts.

There's an old abandoned city bus in Alaska that attracted almost as many tourists to their ruin before it was removed.

 

this guys been down 33 times, and the mariana trench:

james-cameron-titanic-titan-sub

and one time almost spoiled the graph in post #71:

james-cameron-had-near-death-titanic-sub-trip-russian-pilot-2023-6

 

There certainly have been other civilian deaths in the exploration submersible field. Just not at the Titanic. And maybe not seriously deep.

The one I'm thinking of, but haven't yet tracked down, snagged on some wreckage back in the 20th Century. Two people in front survived when rescuers freed the vessel, but the two in back had passed from hypothermia.

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Found it:
https://en.wikipedia.org/wiki/Johnson_Sea_Link_accident

See also the Internet Wayback Machine to this now-offline page:
https://oceangate.com/pdf/manned-sub-safety-statistics.pdf
archived at:
Wayback Machine