Why isn't Titan classed? (2019) • Hacker News Board

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

#191

Post by mustacheemperor » Fri, Jun 23, 2023, 10:41 PM UTC

mechhacker wrote: post #9

dpedu wrote: post #3

Patent for their hull monitoring system: https://patents.google.com/patent/US11119071B1/en

Saw this today. https://www.youtube.com/watch?v=0mSq6ibKKXQ

Interesting, he says the theory he currently finds most plausible and has heard from other experts is that water was able to penetrate the flange connecting the titanium caps to the pressure hull.

So the hull itself may not have been the first to go. But of course that failure is intrinsically connected to the carbon fiber nature of the sub.

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

#192

Post by sitkack » Fri, Jun 23, 2023, 10:42 PM UTC

phkahler wrote: post #162

xupybd wrote: post #79

Earlier quoted context omitted.

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.

Because their development process before a unit test would ever run is so rigorous!

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

#193

Post by micromacrofoot » Fri, Jun 23, 2023, 10:42 PM UTC

nprateem wrote: post #185

Anyone else wondering what was causing the banging every 30m the media seems to have forgotten about? There were reports saying nothing in nature could cause that...

it's the ocean, could have been anything really... someone just desperately read too much into this one

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

#194

Post by _yb2s » Fri, Jun 23, 2023, 10:42 PM UTC

ShroudedNight wrote: post #138

_yb2s wrote: post #103

Earlier quoted context omitted.

This is a really good point... from what I've seen they estimated the strength with Finite Element Analysis in Solidworks, and went for a ~2x margin of safety. There seems to have been no attempt to experimentally determine the expected number of load cycles to failure, they only considered the theoretical case of a perfectly flawless composite with no wear and tear.

Is 2x abstractly reasonable in this context? My [probably flawed] understanding in contexts such as hoisting is that safety margins of 5x are considered a bare minimum. Even crappy "Don't use this to lift things" chain is sold with 3x margins.

Yes, I don't know what the norm is in submarines, but I don't really trust simple engineering models, and think at least 5x is what I'd want in almost any context.

I did see that DeepFlight Challenger, Steve Fossett's unused/untested carbon fiber sub which used the same basic design as Titan, was only built to a 1.5x margin of safety. Experimental tests suggested it was only safe for a one time use, and shouldn't be used for multiple dives.

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

#195

Post by TeMPOraL » Fri, Jun 23, 2023, 10:43 PM UTC

sacnoradhq wrote: post #175

cjensen wrote: post #71

Earlier quoted context omitted.

Yep. This is like saying "who needs building codes because it's more important the owner maintains the roof and paint?" To have something properly function you need both a solid build and maintenance. Doing one well doesn't absolve you of doing the other.

Emperor's new clothes syndrome of the naïve and/or arrogant.

As much as I love the show, I'd call it Star Trek's approach to OSHA. I mean, Starfleet officers are so well-trained and perfect that they don't need safeguards such as guardrails on elevators moving engineers up and down a three story high room that ends up shaking at least twice per episode. And let's not even talk about seatbelts.

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

#196

Post by ikiris » Fri, Jun 23, 2023, 10:43 PM UTC

DebtDeflation wrote: post #8

post-it wrote: post #4

Earlier quoted context omitted.

Highly innovative! Instead of their sudden death being a complete surprise, they may have had a few awful moments of warning.

The engineer who worked on it said it would provide only milliseconds of warning before the hull collapsed. He was promptly fired.

Better than being crushed like their CEO.

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

#197

Post by sacnoradhq » Fri, Jun 23, 2023, 10:43 PM UTC

sebzim4500 wrote: post #94

stickfigure wrote: post #73

Earlier quoted context omitted.

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.

I don't think I'd go on a shuttle, but I would definitely on a crew dragon and I'd probably go on new shephard (I might buy a ticket if the price comes down a bit). There's no way in hell I'm getting on one of virgin galactic's death traps, that looks 10 times worse than the space shuttle.

The Shuttle was driven by USAF "military" needs that didn't matter. Gliding and maneuvering served zero mission purpose. It should've reduced horizontal delta v to zero like a Falcon engine and had an ablation shield. Like many military-involved projects, it was also far too expensive, complex, and fragile. These fundamentals made the Shuttle unnecessarily risky that proved out in its lifecycle.

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

#198

Post by deelowe » Fri, Jun 23, 2023, 10:45 PM UTC

erik_seaberg wrote: post #87

deelowe wrote: post #77

Earlier quoted context omitted.

I thought the deepest it had gone was 3000 meters and there's no evidence of it even having been tested to 4k.

They had two successful trips to Titanic, and other tests in the Bahamas.

On the Titan? I thought this particular sub had never been down that far.

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

#199

Post by [deleted] » Fri, Jun 23, 2023, 10:46 PM UTC

proggy wrote: post #178

stickfigure wrote: post #73

Earlier quoted context omitted.

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.

One of the shuttle missions that resulted in loss of crew was caused by operating the vehicle outside of the rated temperature envelope (for the SSB O-rings). If that requirement was honored, the failure rate could have been halved. The other loss of crew was caused by a genuine oversight in the design of the system, in that the orbiter was always susceptible to strikes from insulating foam falling from the external…

[deleted]

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

#200

Post by [deleted] » Fri, Jun 23, 2023, 10:47 PM UTC

TeMPOraL wrote: post #195

sacnoradhq wrote: post #175

Earlier quoted context omitted.

Emperor's new clothes syndrome of the naïve and/or arrogant.

As much as I love the show, I'd call it Star Trek's approach to OSHA. I mean, Starfleet officers are so well-trained and perfect that they don't need safeguards such as guardrails on elevators moving engineers up and down a three story high room that ends up shaking at least twice per episode. And let's not even talk about seatbelts.

[deleted]