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Why isn't Titan classed? (2019)

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Re: Why isn't Titan classed? (2019)

#161

Post by qayxc »

AlbertCory wrote: post #108
advael wrote: post #78

What a profoundly stupid take by a profoundly irresponsible company. This is a great example of why you should consider anything a company says about itself to be marketing, and treat it with commensurate skepticism. "We're so innovative we don't have time for safety regulations" - An idiot, destined to harm someone unless pure dumb luck causes their company to fail first

> We're so innovative what I'm wondering is: what's the incentive to be "innovative" in the first place? Unless "innovation" is an end in itself. Is there some great unmet need to send people to extreme depths, especially when unmanned probes can do most necessar work nowadays?

> Is there some great unmet need to send people to extreme depths, especially when unmanned probes can do most necessar work nowadays?

Two reasons: 1) they had plenty of paying customers, so there was a demand

2) the CEO wanted to be remembered as an innovator, views this as being an explorer, and wanted to inspire people (he said so in interviews)

Re: Why isn't Titan classed? (2019)

#162

Post by phkahler »

xupybd wrote: post #79
DeRock wrote: post #56

Earlier quoted context omitted.

Their reasoning is fundamentally flawed. > The vast majority of marine (and aviation) accidents are a result of operator error, not mechanical failure. As a result, simply focusing on classing the vessel does not address the operational risks. Aka "classing doesn't mitigate all problems, so we're not going to do it at all"

I've heard the same argument against unit testing and strong typing.

If I recall correctly, even NASA found unit testing to be of limited value, finding a small fraction of software bugs. That's not to say "don't do it" but my stance is that the developer should do some ad-hoc testing for everything they write, just don't formalize and document it or you'll land on the wrong end of cost/benefit.

I can point to some subtle logic bugs that no sane unit test would have caught.

Re: Why isn't Titan classed? (2019)

#163

Post by programd »

stickfigure wrote: post #73
cbzoiav wrote: post #16

> The vast majority of marine (and aviation) accidents are a result of operator error, not mechanical failure. Could that be because the vast majority of mechanical designs go through processes designed to validate them and catch flaws? They also use SpaceX as an example. SpaceX ran a large number of unmanned launches to prove out the design before putting people on board. Several of those ended in loss of the vehicl…

The first space shuttle launch was crewed. It ended up with a ~2% failure rate. The Titan made about 50 dives. So, from a reliability perspective, on par with the shuttle. I posit that half the people on HN would volunteer for a hypothetical next shuttle flight without thinking twice.

Space Shuttle - "a ~2% failure rate"

Which incidentally was exactly what the engineering studies predicted while it was being designed. Which really says something about the quality of engineering analysis which went into creating the Shuttle.

For reference you can nerd out on the following awsome books:

"Space Shuttle Decision, 1965-1972 (History of the Space Shuttle, Volume 1)"

"Development of the Space Shuttle, 1972-1981 (History of the Space Shuttle, Volume 2)"

Re: Why isn't Titan classed? (2019)

#165

Post by mustacheemperor »

hadlock wrote: post #158
ajross wrote: post #37

Earlier quoted context omitted.

That's exactly it. If OceanGate had build and dropped a few dozen of these hulls empty, as many times as needed to reach failure, whatever design flaw caused the implosion almost certainly would have been noticed. It's the hubris of diving in what amounts to a prototype that's at issue here, not any fundamental technical mistake.

The design flaw was that they used a construction material strong in tension, but weak in compression. For a task that is almost entirely compression. On a vehicle that has no need for weight savings. Also in a couple photos looks like they have drilled and screwed a monitor mount directly into the pressure vessel, creating future failure points, rather than gluing a piece of plywood to the hull and screwing into tha…

>On a vehicle that has no need for weight savings

Most deep sea submersibles only seat a couple people, which wouldn't work for the 'titanic tourism carnival ride' business model. I would guess the weight savings were intended to enable a sub with more capacity that could still be winched on and off the support ship without more complex/expensive heavy lifting equipment.

Re: Why isn't Titan classed? (2019)

#169

Post by _yb2s »

Alupis wrote: post #44
ARandomerDude wrote: post #34

Earlier quoted context omitted.

That’s pretty wild. The operator was able to tell when they were going deeper based on the sound of the carbon fibers cracking in the hull.

These sort of sounds occur even in metal (steel/titanium) submersibles.

I would say that is different. A steel part will make sounds as it rapidly flexes under pressure or temperature cycling, but those sudden movements can be within the "endurance limit" of the material, and not lead to fatigue or failure.

The hull sounds they were hearing in Titan were likely snapping of carbon fibers (based on the linked video above), which means a permanent reduction in strength each time it happens.

DeepFlight Challenger, the unused submarine that pioneered this type of design, was intended only for single use:

"But the company that built DeepFlight Challenger has told The Telegraph it refused to back the project, insisting the submarine was suitable for only one dive and could not be reused because of the pressure on its structure at such depths."

"The problem is the strength of the vessel does decrease after each dive. It is strongest on the first dive.” https://www.telegraph.co.uk/news/science/science-news/112919...

Re: Why isn't Titan classed? (2019)

#170

Post by lb1lf »

RajT88 wrote: post #47
ARandomerDude wrote: post #34

Earlier quoted context omitted.

That’s pretty wild. The operator was able to tell when they were going deeper based on the sound of the carbon fibers cracking in the hull.

Holy Shitballs. Cracking noises! Things which you never want to hear on a submersible! (insert "this is fine" meme)

You hear those in conventional subs, too, as you go deeper the hull makes all sorts of worrying creaks. (During a sea trial, I had to be aboard a sub from $NAVY diving to 900 feet and change - the crew assured me the sounds were normal...)
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