The cave divers who went back for their friends

Re:The cave divers who went back for their friends by kh_hk on Monday May 09, 2016 @05:03AM (#11658401)

I feel similarly. However the article notes:

> Having the bodies would help the families grieve, and would also help to prevent lengthy delays to insurance and inheritance settlements.

Risking lives to recover dead bodies does not sound logical and yet it's the norm on underwater accidents. One of the multiple examples of a recovery gone wrong is the case of David Shaw [1], particularly famous because there's footage of the recovery accident.

[1]: https://en.wikipedia.org/wiki/David_Shaw_(diver)#Last_dive

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Re:The cave divers who went back for their friends by blubb-fish on Monday May 09, 2016 @05:25AM (#11658474)

> Risking lives to recover dead bodies does not sound logical

You're a green-blooded, heartless monster, Mr. Spock ...

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Re:The cave divers who went back for their friends by kh_hk on Monday May 09, 2016 @05:35AM (#11658525)

It does not sound logical. Every time there's an underwater accident (including plane/helicopter accidents and shipwrecks), popular sentiment is on the same line: "why put lives in danger for dead ones" so there must be another reason for sending divers down there (other than feeling logical or not):

- Something related to body identification and insurance.

- Human life is cheaper than ROVs.

- There are tasks that ROVs can't accomplish.

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Re:The cave divers who went back for their friends by LanceH on Monday May 09, 2016 @09:48AM (#11659782)

One of the reasons is the bond between the living who continue the dangerous pursuit. It is a statement between them that nobody gets left behind. That is the level of commitment needed; unequivocal and unending.

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Re:The cave divers who went back for their friends by harlanlewis on Monday May 09, 2016 @11:54AM (#11660762)

It's interesting to contrast this with mountaineering, and the many corpses pointing the way to Everest's summit. Some have nicknames.

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Re:The cave divers who went back for their friends by rrauenza on Monday May 09, 2016 @12:58PM (#11661288)

Shaw's story: http://www.outsideonline.com/1922711/raising-dead

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Re:The cave divers who went back for their friends by biswaroop on Monday May 09, 2016 @05:14AM (#11658436)

Surely an ROV could be tasked to this effort (at least for the identification part for insurance).

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Re:The cave divers who went back for their friends by timclark on Monday May 09, 2016 @05:21AM (#11658457)

How would the ROV be controlled? Radio won't work. Long cables are problematic in cave environments, they snag, they get pulled by currents.

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Re:The cave divers who went back for their friends by imglorp on Monday May 09, 2016 @08:46AM (#11659365)

There are wire guided torpedoes and missiles that carry a spool with them and pay it out as they travel. Presumably this is a good thing because it can't be intercepted and jammed. Anyway, that missile carries 4200m of wire, which would be plenty for an ROV to explore most of the cave in the article before sending people, who could follow its wire.

https://en.wikipedia.org/wiki/BGM-71_TOW

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Re:The cave divers who went back for their friends by cturner on Monday May 09, 2016 @09:28AM (#11659643)

You can't touch the sides in cave diving. It generates silt which destroys visibility.

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Re:The cave divers who went back for their friends by imglorp on Monday May 09, 2016 @09:48AM (#11659787)

Yup that's fine. If the ROV kicks up any silt, shut it down and go for lunch. Nobody's air is running out so you have extra time.

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Re:The cave divers who went back for their friends by chongli on Monday May 09, 2016 @07:12AM (#11658881)

There's no current down in these caves. The logical solution then is to drop a trail of breadcrumb beacons to relay your signal along, either via light or some radio band that penetrates water halfway decently.

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Re:The cave divers who went back for their friends by callahad on Monday May 09, 2016 @09:27AM (#11659624)

Are you certain? I've spent most of my dives in Florida springs, which can have flow rates above 100 cubic feet per second. You can basically get blown out of Devil's Eye at Ginnie Springs if you're not careful with your trim when ascending.

The downside of still systems is that any silt you stir up can kill the visibility for hours / days, which would cause problems for light-based beacons.

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Re:The cave divers who went back for their friends by adrianN on Monday May 09, 2016 @05:28AM (#11658486)

I wonder how much bandwidth a sonar link can provide over reasonable distance.

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Re:The cave divers who went back for their friends by simonh on Monday May 09, 2016 @06:25AM (#11658702)

The a highly restricted, complex cave environment with echoes all over the place? Probably not much.

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Re:The cave divers who went back for their friends by caf on Monday May 09, 2016 @08:35AM (#11659276)

I suspect you could use the echoic environment to your advantage with a MIMO type system.

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Re:The cave divers who went back for their friends by amelius on Monday May 09, 2016 @05:37AM (#11658533)

The ROV can drop an amplifying transceiver every so many meters?

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Re:The cave divers who went back for their friends by biswaroop on Monday May 09, 2016 @05:51AM (#11658589)

How do divers communicate over long distances? If they don't, that's something worth solving in its own right. If they do, couldn't the ROV use the same thing?

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Re:The cave divers who went back for their friends by gaius on Monday May 09, 2016 @06:20AM (#11658679)

Light signals. You can say 3 things over any distance, which are "OK" (as a question or a response), "attention please" and "OMG OUT OF GAS NEED HELP IMMEDIATELY".

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Re:The cave divers who went back for their friends by Piskvorrr on Monday May 09, 2016 @06:35AM (#11658735)

Given clear visibility, which gets rarer and rarer with distance - and even more so in constrained spaces, which are unlikely to be pure bedrock. Also, line of sight.

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Re:The cave divers who went back for their friends by gaius on Monday May 09, 2016 @06:37AM (#11658746)

Indeed. So you see operating a ROV like that is a non-starter.

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Re:The cave divers who went back for their friends by Piskvorrr on Monday May 09, 2016 @10:20AM (#11660014)

I never said otherwise; are you sure you are not replying to somebody else?

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Re:The cave divers who went back for their friends by Piskvorrr on Monday May 09, 2016 @06:28AM (#11658714)

They don't. GL;HF.

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Re:The cave divers who went back for their friends by jkestner on Monday May 09, 2016 @01:26PM (#11661496)

Also, cultural: Finns also have a proud history of going to great lengths to retrieve the bodies of deceased friends.

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