Titanic tourist submersible goes missing with search under way • Hacker News Board

Re: Titanic tourist submersible goes missing with search under way

#561

Post by nradov » Tue, Jun 20, 2023, 4:55 PM UTC

jskrablin wrote: post #505

zarzavat wrote: post #490

Earlier quoted context omitted.

Honest question, why do it? What’s the attraction of cave diving? Are underwater caves exciting enough that it’s worth the risk? Or is the risk itself the main thrill? Or is your perception that it’s not that risky? I can understand the attraction of e.g. wingsuits, because the idea of flying like a bird is compelling, even if I would never risk my own life to do it. Although there’s definitely more than a few wingsu…

Adrenaline is a powerful drug. And there's also a 100% focus (or very close to it), something that's really hard to achieve otherwise. Keeping yourself fit counts as well. I don't cave dive but I do ride MX which is also considered a risky sport. I'd say you'll hear similar answers from everyone dealing with risky sports/activities.

It's not an adrenaline thing. Cave dives last for hours, not a few seconds like BASE jumping. If anything cave explorers do everything they can to minimize adrenaline production in order to hold their breathing rates down.

Re: Titanic tourist submersible goes missing with search under way

#562

Post by BoryAlis » Tue, Jun 20, 2023, 4:55 PM UTC

michaelt wrote: post #76

zabzonk wrote: post #61

Earlier quoted context omitted.

> 13,000 ft titanic is at about 12500, according to wkikipedia - a bit close?

Given that it's named the "Titan" and described as "the world's only privately owned manned-submersible capable of reaching Titanic depths of 4000 meters" [1] I suspect this was designed with the Titanic in mind. You would hope that would include a substantial safety margin. [1] https://www.youtube.com/watch?v=vNHXqOUtxgw

"Titan" - an ominous omen.

Re: Titanic tourist submersible goes missing with search under way

#563

Post by iancmceachern » Tue, Jun 20, 2023, 5:04 PM UTC

Animats wrote: post #446

Twitter video of vessel.[1] Not encouraging. [1] https://twitter.com/FnpMarieOH/status/1670931677013524487

Exactly. Judging from that video their approach to designing and building that thing seeks very amateurish, nonchalant, and lacking an eye for redundancy and safety.

Re: Titanic tourist submersible goes missing with search under way

#564

Post by nradov » Tue, Jun 20, 2023, 5:07 PM UTC

belorn wrote: post #549

ck2 wrote: post #430

Earlier quoted context omitted.

All the dead frozen bodies on Mount Everest are a testimony to risk hand-waving. But I short-circuit trying to figure which is more stupid, visiting Everest or Titanic. People want an "adventure" and to learn useful things about themselves? Okay train to run a marathon. Now train to run it faster.

Running is a very high injury rate sport. Depending on what study you look at, novice runners has an accident rate of around 3.3 (that requires medical attention) per 100h of running. It is not without its own risk. Lower risk than climbing Everest or visiting Titanic, but still fairly high risk activity in a city environment with city traffic. Swimming is a bit better if one want to a lower-risk sport.

Musculoskeletal overuse injuries requiring some level of medical attention are pretty common in every endurance sport, including swimming. But the number of people who actually die due to running accidents is miniscule. We usually have a few deaths every year in open water swimming and the swim portion of triathlon races due to medical issues like heart attacks and immersion pulmonary oedema.

Re: Titanic tourist submersible goes missing with search under way

#565

Post by TecoAndJix » Tue, Jun 20, 2023, 5:17 PM UTC

minedwiz wrote: post #267

systemtest wrote: post #241

Earlier quoted context omitted.

Is there some sort of underwater "GPS" tracker they can use to track the sub?

Communicating with submarines is actually a nightmare. The saltwater ruins most radio communications, so you have no chance to receive GPS signals, which are pretty weak even on the surface. One thing the military does/did to communicate with subs is use low-bandwidth text-only very low frequency radio, but you need colossal transmitters and there's no way the mother ship carries one. Hydrophones are also an option,…

INT ZBZ

Re: Titanic tourist submersible goes missing with search under way

#566

Post by omniglottal » Tue, Jun 20, 2023, 5:20 PM UTC

bob778 wrote: post #428

paulpauper wrote: post #339

Earlier quoted context omitted.

but the op said "If the mother ship can not find the sub the occupants could be trapped bobbing just below the surface until their air runs out." just beneath the surface

In submersible tech, just beneath the surface is 0-30m depth basically (for salt water). Cellphones signals are about 2m max while higher frequencies (eg 2.4GHz) drop off exponentially so are <1m

Antennea can trivially extend over 30m, and can float on the surface. As a wire attached to an inflatable float, for either bidirectional communication or as a GPS beacon, or both, the complete solution could exist for less than $10k and less than 10 kilograms to solve this. Why doesn't this exist for this craft that can only be openned from the outside?? There exists the ability to communicate from directly above, so why can't it also communicate (further) through open air while bobbing near the surface?

Re: Titanic tourist submersible goes missing with search under way

#567

Post by jliptzin » Tue, Jun 20, 2023, 5:37 PM UTC

varjag wrote: post #496

bagels wrote: post #356

Earlier quoted context omitted.

Tradition itself is probably the worst rationale for an engineering solution. Maybe it's the right way for other reasons?

You know what's the worst? Someone barging in into an established engineering domain and making spot judgements. This is simply incredible hubris that often is the hallmark of stupid but educated people. If some brilliant improvement occurred to you in the first 5 seconds of hearing about some technical solution chances are this thought visited others in the past 100 years working on the problem for a living. And if…

It sounds like they could use some improvements, 5 people are probably dead now. Out of how many trips in that submersible? I don’t know, just wondering, but it can’t be that many. Certainly not comparable to commercial airlines. So that’s a pretty high failure rate. Being able to open the vessel from the inside in an emergency probably wouldn’t have saved them, it’s just the first thing that is too much of a red flag for me to personally ever step foot in that thing.

I also don’t even understand why that vessel needs to be manned at all. With today’s high def cameras and displays, including VR, they could outfit an unmanned vessel with high def cameras everywhere, a fiber optic tether to the surface to carry the high def signal (or even wireless to some degree if they could make that work), and the operator could sit in a control station either on the boat at the surface or streamed over the internet from home, controlling the vessel however he wants, with high def screens to simulate the viewing experience of being in the vessel. I’ll bet it would get you 99% of the way there without having to risk your life. It’s not like anyone is getting out of the thing to swim around the titanic in scuba gear anyway.

Re: Titanic tourist submersible goes missing with search under way

#568

Post by system2 » Tue, Jun 20, 2023, 5:40 PM UTC

waste_monk wrote: post #460

system2 wrote: post #386

Earlier quoted context omitted.

Why not sonar then?

If you mean "why aren't they using sonar to locate the missing vessel", I'm sure they're trying. One of the articles about this event I saw mentioned a P-8 Poseidon being deployed to assist the search. I would be extremely surprised if at least a few sonobouys hadn't been deployed. If you're asking why they don't have a acoustic phone for underwater communications, I couldn't tell you. As I understand the Janus digit…

Makes more sense. I believe they were skimping on the necessary safety measurements.

Re: Titanic tourist submersible goes missing with search under way

#569

Post by spadros » Tue, Jun 20, 2023, 5:41 PM UTC

johnwalkr wrote: post #473

WalterBright wrote: post #398

I'm surprised the craft doesn't have a pinger, like airplane black boxes do (and those can survive on the ocean floor, too). 96 hours of oxygen won't help if it takes 200 hours just to find where they are.

They can survive on the ocean floor but definitely not ping from there.

The Trieste dive to the bottom of Mariana Trench were able to use voice communications from the sea floor. Should be possible from Titanics depths then, seeing as Mariana’s is 3x deeper. Assuming the sub hasn’t already imploded, that is.

Re: Titanic tourist submersible goes missing with search under way

#570

Post by omniglottal » Tue, Jun 20, 2023, 5:48 PM UTC

midoridensha wrote: post #491

JumpCrisscross wrote: post #245

Earlier quoted context omitted.

> Composite properties can be fairly accurately measured and tested, just like any other material including plate steel or aluminium Metals are uniform and broadly predictable. Composites vary cure to cure. We simply don’t have the deep engineering tables that let you know how a material will behave without destructive testing.

>Metals are uniform and broadly predictable. That's not true at all: metals have a grain structure, and how those grains are oriented can change the metal's properties in different directions. >Composites vary cure to cure. Metal castings can vary from cast to cast.

Forging and heat treatment are processes to introduce uniformity of metallic grain structures. These have been perfected over hundreds of years. I challenge you to find a single structural component in a safety-critical context which is made of cast metal.