Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Titanic tourist submersible goes missing with search under way

bbc.com

Post reply on HN
Print view View original

401–410 of 649 posts

Re: Titanic tourist submersible goes missing with search under way

#401

Post by porknubbins »

boomboomsubban wrote: post #336
MagicMoonlight wrote: post #162

Earlier quoted context omitted.

If your design breaks at less than the target then you really have to question the logic of continuing with that design. Making it slightly bigger won't fix the inherent issue with the materials. They're potentially opening themselves up to charges for killing these people. They knowingly or recklessly put them on a boat when it isn't capable of reaching the depth safely and now they are dead.

>They're potentially opening themselves up to charges for killing these people. They knowingly or recklessly put them on a boat when it isn't capable of reaching the depth safely and now they are dead. Would the fact they almost certainly got the people to sign a fairly extensive release before they took them into international waters be relevant? I don't know how much of the "anything goes on the sea" thing is a myt…

“anything goes at sea” is definitely not right. I think international waters is pretty meaningless from an individual standpoint since the individual or company would always be under the jurisdiction of the ship’s registration as well as their own country (for lots of laws, such as you can’t sail off shore on a foreign ship and cheat on your taxes). International waters is mostly relevant for countries.

Re: Titanic tourist submersible goes missing with search under way

#402

Post by Scoundreller »

pfdietz wrote: post #335
kortex wrote: post #47

Earlier quoted context omitted.

I'm not really an engineer (general hobbyist, former chemist) but I have built and worked with pressure and vacuum vessels. Positive pressure (tank vs exterior) is much easier to deal with than negative pressure (vacuum vessel at 1 atm, or bathyscape with 1 atm inside and high pressure exterior). In positive pressure, your stress is mostly in the hoop mode, which is stable. This is why aluminum cans can be so thin. I…

> a buckling mode, which is inherently unstable. As soon as it goes, it goes all at once. Example of implosion of a railroad tank car: https://www.youtube.com/watch?v=Zz95_VvTxZM

Or this: https://www.youtube.com/watch?v=0N17tEW_WEU

Re: Titanic tourist submersible goes missing with search under way

#403

Post by userbinator »

scarnz wrote: post #30

This appears to be the vessel in question: https://oceangate.com/our-subs/titan-submersible.html Pressure hull made from titanium and carbon fiber, capable of diving to 4000m (13,000 ft). I recall that one reason SpaceX switched from carbon fiber to stainless steel pressure vessels (fuel tanks) was the difficulty of detecting structural flaws. Can any engineers comment on whether that task is easier for a vessel expo…

I wonder if it has an adaptive pressurisation system, similar to airplanes but in the opposite direction, where the internal pressure is allowed to increase up to a certain point as it descends to reduce the pressure differential.

Re: Titanic tourist submersible goes missing with search under way

#404

Post by Scoundreller »

readams wrote: post #68
kortex wrote: post #47

Earlier quoted context omitted.

I'm not really an engineer (general hobbyist, former chemist) but I have built and worked with pressure and vacuum vessels. Positive pressure (tank vs exterior) is much easier to deal with than negative pressure (vacuum vessel at 1 atm, or bathyscape with 1 atm inside and high pressure exterior). In positive pressure, your stress is mostly in the hoop mode, which is stable. This is why aluminum cans can be so thin. I…

Also space pressure difference is much less. A fuel tank might have just a few atmospheres inside, and of course a human pressure vessel will have a bit under 1 atmosphere inside, compared to the outside which is at ~0 atm. At 4000m, the outside pressure is _400_ atmospheres compared to just one inside. It's way, way harder.

TIL my bicycle tires are at 4 atm, and higher-end ones 8, and racing ones will do 11.

Re: Titanic tourist submersible goes missing with search under way

#405

Post by 8675309t »

MengerSponge wrote: post #140
kortex wrote: post #47

Earlier quoted context omitted.

I'm not really an engineer (general hobbyist, former chemist) but I have built and worked with pressure and vacuum vessels. Positive pressure (tank vs exterior) is much easier to deal with than negative pressure (vacuum vessel at 1 atm, or bathyscape with 1 atm inside and high pressure exterior). In positive pressure, your stress is mostly in the hoop mode, which is stable. This is why aluminum cans can be so thin. I…

[flagged]

[flagged]

Re: Titanic tourist submersible goes missing with search under way

#407

Post by anyfoo »

jhugo wrote: post #392
anyfoo wrote: post #381

Earlier quoted context omitted.

How many are there and what do they do?

How many? No idea. But it's common to find it offered as a commercial activity — in a similar way to skydiving or other "extreme sports" — all over the world, as a quick web search would show you…

Can you show me a few? I did the quick web search as suggested, but cannot find the right keywords to find a lot.

What I did find is that BASE jumping is apparently often illegal (but definitely not everywhere per se), that everyone who did it can claim a “number”, and that 2000 numbers total have been claimed since 1981.

I’m not saying you’re wrong, I know next to nothing about BASE jumping. I’m curious what companies offer it commercially as an activity, and if that’s really widespread.

I just remember watching a documentary once, saying how crazy and uncommon it is.

Re: Titanic tourist submersible goes missing with search under way

#408

Post by swader999 »

londons_explore wrote: post #134
svnt wrote: post #127

Earlier quoted context omitted.

I found the (wireless, $30) game controller: https://www.amazon.com/Logitech-Wireless-Nano-Receiver-Contr... and this from a review: “Pretty good controller, fits in hand comfortably and is compatible with anything I throw at it in a Debian linux environment. The conductive pads are extremely low quality though as I've had to replace them 3 times in the 2 years Ive been using it. For a Logitech product I expect bette…

So it's possible this sub is stuck turning in right only circles deep underwater because the left button has broken...

They would just drive upside down for a bit.

Re: Titanic tourist submersible goes missing with search under way

#409

Post by wnevets »

aaron695 wrote: post #156
wnevets wrote: post #145

Earlier quoted context omitted.

unfortunately this sounds like "move fast and break things" in the worst possible way.

It gets boring hearing people who can't program or manage blurt out 'move fast and break things' whenever they hear of failure. Learn to code. Or if you're not smart enough learn project management. Alternatively stop using sayings in other peoples fields. Do something dumb like journalism.

Its amusing that you think that I don't program. Ultimately hacker news is a tech focused hub and home to a lot of devs where that phrase resonates.

Re: Titanic tourist submersible goes missing with search under way

#410

Post by fastball »

moffkalast wrote: post #315
spokeroni wrote: post #256

Earlier quoted context omitted.

> I assume this submersible is using electromagnetically attached drop-weights so that if anything goes wrong and power is lost I don't think they have any "drop-weights" which would make them positively buoyant. If I'm reading the spec-sheet correctly, the submersible itself weights ~1500lbs. Subs have ballast tanks which they pump with air and force out water to make themselves positively buoyant. But if something…

There are typically compressed air cylinders that can expel the water in case of emergency. At least on military submarines that go down to 300m, it may not work 4km down where the pressure is ridiculous. https://en.wikipedia.org/wiki/Emergency_main_ballast_tank_bl...

Yep, I believe it would be almost impossible to have air tanks that are pressurized enough to blow out water from ballast tanks at that depth.
Post reply on HN