Two days in an underwater cave running out of oxygen • Hacker News Board

Re: Two days in an underwater cave running out of oxygen

#241

Post by cr1895 » Tue, Jul 18, 2017, 6:12 AM UTC

stingraycharles wrote: post #240

titanomachy wrote: post #31

Earlier quoted context omitted.

I'm not familiar with Mallorca's hydrogeology, but I've done some cenote (cavern) diving in Mexico's Yucatan peninsula. The caves are inland, but sea water infiltrates through the porous and channel-filled rock. The water nearer the surface is rainwater. The narrow region where freshwater and seawater intermingle is called the halocline, it creates a cool optical distortion which reminds me of the "oil paint" filter…

This probably is a stupid question, but wouldn't the salty seawater be lighter than the rain water, and thus be at the surface ?

Salty water is quite literally more dense than fresh water. Average seawater is 1025 kg/m^3, pure water is nominally 1000 kg/m^3.

Somewhat related video: dense brine that doesn't freeze in Arctic sea ice sinks rapidly through liquid seawater below

https://youtu.be/WyWn1XJ9kTE

Re: Two days in an underwater cave running out of oxygen

#242

Post by irrational » Tue, Jul 18, 2017, 6:28 AM UTC

throwawaycanada wrote: post #218

aesh2Xa1 wrote: post #160

Earlier quoted context omitted.

That doesn't sound right. How many cave-going dads are there that you could make the claim? And do a majority of kids believe their fathers are boring? I just don't buy it. And is taking a risk like this the best way to be "not boring?" Definitely don't buy it. You can have fun and be adventurous without taking heavy risks. It's fair to say that someone who continues to put himself at harm is foolish in one capacity…

I don't think it is possible in the literal sense to have adventure without risk.

Maybe it depends on your definition of adventure or risk. I went to an escape room recently for the first time. I considered that to be an adventure for me. But I never felt like I was taking a risk.

Re: Two days in an underwater cave running out of oxygen

#243

Post by Simon_says » Tue, Jul 18, 2017, 6:30 AM UTC

coleifer wrote: post #40

j9461701 wrote: post #33

I might be speaking out of line, but taking on these kinds of risks with young children at home seems kind of selfish. The fact that he went back into the same cave that nearly killed him only a month later...almost as if to say: "I would rather my kids grow up without a Dad than live without my adrenaline fix" I am neither a father or a cave diver though, so I might be missing a piece of the puzzle. Would either gro…

I race motorcycles and also ride on the street most days, so this is a familiar topic of discussion with my wife, especially considering that we have a two-year-old son. What I can say on the subject is that there's a big difference between taking every precaution to minimize risk and being careless or reckless. What stood out to me when reading this article was "why the fuck would you use a guideline that could brea…

There's probably an order of magnitude or two difference in risk between cave diving and motorcycle racing. Cave diving is really dangerous.

Re: Two days in an underwater cave running out of oxygen

#244

Post by irrational » Tue, Jul 18, 2017, 6:32 AM UTC

laumars wrote: post #172

pragone wrote: post #166

Earlier quoted context omitted.

> Given the choice of having a father at home or have one dead in cave but famous for exploring cool places I don't think it's hard to guess what most children would pick. In all seriousness, I do have a hard time guessing which one most children would pick. I can see reasonable arguments made on either side. Personally, I think it would be far more inspiring to have a father who died pursuing his passion, then one w…

Depends on the kid, their age and their relationship with their father. I don't think there is any right generalized answer. With my kids I know they would rather have me around, but they are young so I'm already "superman" to them. Who knows how our relationship will change as they grow older.

As they go through their teenage years you will get stupider and lamer in their eyes. Then sometime after they move out they will realize that you are actually quite intelligent and will, at some point, apologize for being an ass and tell you that they are proud of you. At least that was my experience with my parents and has been my experience with my kids so far.

Re: Two days in an underwater cave running out of oxygen

#245

Post by stingraycharles » Tue, Jul 18, 2017, 6:48 AM UTC

cr1895 wrote: post #241

stingraycharles wrote: post #240

Earlier quoted context omitted.

This probably is a stupid question, but wouldn't the salty seawater be lighter than the rain water, and thus be at the surface ?

Salty water is quite literally more dense than fresh water. Average seawater is 1025 kg/m^3, pure water is nominally 1000 kg/m^3. Somewhat related video: dense brine that doesn't freeze in Arctic sea ice sinks rapidly through liquid seawater below https://youtu.be/WyWn1XJ9kTE

Oh geez, you're absolutely right, I don't know what I was thinking. I probably needed my morning coffee.

Re: Two days in an underwater cave running out of oxygen

#246

Post by Someone » Tue, Jul 18, 2017, 7:15 AM UTC

jonahx wrote: post #214

pragone wrote: post #166

Earlier quoted context omitted.

> Given the choice of having a father at home or have one dead in cave but famous for exploring cool places I don't think it's hard to guess what most children would pick. In all seriousness, I do have a hard time guessing which one most children would pick. I can see reasonable arguments made on either side. Personally, I think it would be far more inspiring to have a father who died pursuing his passion, then one w…

If you just asked them, in all their ignorance, you're undoubtedly right. If you asked the children who chose the adventurous dad after he had died pursuing his passion, nearly 100% would trade the world to reverse that choice.

The 'choice' isn't between "dull and alive" and "adventurous and dead", but between "dull, 99.9% chance of living to an old age" and "adventurous, 95% chance of living to an old age" (actual percentages for illustration only)

I think many kids, especially those with an adventurous mom/dad, would think "my mom/dad is strong and knows what he is doing, so (s)he won't be in that 5%"

Re: Two days in an underwater cave running out of oxygen

#247

Post by dx034 » Tue, Jul 18, 2017, 7:22 AM UTC

matt4077 wrote: post #111

idlewords wrote: post #93

Earlier quoted context omitted.

A similar trough exists in general aviation—accident rates are markedly higher for somewhat experienced pilots than for beginners. The consensus among pilots seems to be that you are most dangerous between the time you think you know what you're doing, and the time you survive your first big scare. There's probably a good lesson here for computer programmers...

I seem to remember hearing the same about drivers. Might have been for my country (Germany) specifically, where the minimum age for a license 18. If you get your license at 16, you're still in the upwards swing on risk-taking behaviour, which might drown out all other statistical signals.

Yes, the most dangerous drivers tend not to be the ones who just got their license, as they usually still adapt and don't drive too fast. It becomes dangerous after a few months or 1-2 years when a driver feels confident enough even though he still has very little experience.

Re: Two days in an underwater cave running out of oxygen

#248

Post by dx034 » Tue, Jul 18, 2017, 7:23 AM UTC

idlewords wrote: post #229

mveety wrote: post #178

Earlier quoted context omitted.

I disagree here. You're dangerous until you know you know what you're doing. Having a bad scare might make you not repeat that situation, but you're still just as dumb after it as you were before (well, at least that's been true for me).

You can disagree, but I'm talking about an objective phenomenon. https://www.amazon.com/Killing-Zone-Second-How-Pilots/dp/007...

> when they leave their instructors behind and fly as pilot in command for the first time

This is very different. If an instructor is present the danger is clearly lower. The book deals with the phase where pilots first fly alone without external help.

Re: Two days in an underwater cave running out of oxygen

#249

Post by austinjp » Tue, Jul 18, 2017, 7:44 AM UTC

A_Person wrote: post #208

I'd like to address the false assumption in this thread that cave diving is more dangerous than driving a car! I cave dive on a regular basis with two other guys. We've dived together as a team for nearly 10 years. I'm late 60s and single, the second guy is 50s and has a partner but no children, and the third is early 40s with a six-year-old, who he has every intention of seeing grow-up into adulthood. We often dive…

> there and back is a five hour drive. During that drive, you could fall asleep and run off the road; have local fauna run out in front of your car; get head-on crashed by drunken drivers, and so on.

> there are risks like tunnels collapsing and blocking the exit. But statistically, I'm sure that those are orders of magnitude less likely than having a heart attack, or falling over and breaking your neck.

Unfortunately I believe you're making an error in how you interpret statistics. These risks exist in addition to the other risks of cave diving, not instead of. Your risk of heart attack or driving incident are already at a certain level. By cave diving you are adding risks such as tunnel collapse or disorientation underwater.

While it's clear that you do plenty to mitigate those risks, they are not reduced to zero. So, all other things being equal, your risk of death is higher than others in your cohort.

But I'm glad you clearly enjoy your hobby, and I fully respect you for that :)

Re: Two days in an underwater cave running out of oxygen

#250

Post by hueving » Tue, Jul 18, 2017, 7:47 AM UTC

pdonis wrote: post #224

hueving wrote: post #200

Earlier quoted context omitted.

Your life being the thing on the line.

Since I talked about life insurance, obviously I'm talking about cases where your life is on the line. So does that mean you should never do anything that might get you killed if you have children? Even if you have life insurance?

>So does that mean you should never do anything that might get you killed if you have children?

You should probably avoid things that cause life insurance rates to jump up. That's a good barometer for excessive risk.

>Even if you have life insurance?

Parents and money are not substitute goods. Life insurance is helpful for financial security, but it doesn't account for the detriment to being raised by a single parent.