Du'an Guangxi China Cave Diving Accident

[eelnoraa]

At the very bottom of the report, it mentions the support diver, Zhou Pei, is using double backgas, with a 50% deco and a 100% deco. Backgas is air.

In section 5: At 90m, Yuan left hand touched some rock. Yuan used right hand to shine light to gauge, he read 40 bar. Yuan was thinking just another 15m to the next available gas. At the same time, Yuan notice Tao is floating up pass him. Yuan try to catch Tao but no success. And Tao disappear above Yuan. Long hose dropped. It all happen in a split of a second .....

So it appears that Tao lost conscience while breathing on Yuan's long hose. Tao then floated up passing Yuan, dropping the long hose and disappeared. This happened 15m before they made it to 75m which is where their stage were.

 

[Dr. Lecter]

"deep stage using BULHMAN form, the latter half of decompression using the bubble theory"

That seems backwards, but it's probably a translation issue.

 

[Mike.D]

At the very bottom of the report, it mentions the support diver, Zhou Pei, is using double backgas, with a 50% deco and a 100% deco. Backgas is air.

In section 5: At 90m, Yuan left hand touched some rock. Yuan used right hand to shine light to gauge, he read 40 bar. Yuan was thinking just another 15m to the next available gas. At the same time, Yuan notice Tao is floating up pass him. Yuan try to catch Tao but no success. And Tao disappear above Yuan. Long hose dropped. It all happen in a split of a second .....

So it appears that Tao lost conscience while breathing on Yuan's long hose. Tao then floated up passing Yuan, dropping the long hose and disappeared. This happened 15m before they made it to 75m which is where their stage were.

So he may have passed out while breathing from the long hose? Hyper ventilating, working to hard?? Hmm


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[Peter69_56]

My sympathy for you. I can only imagine how you would feel to lose a very close friend. You plan the dive and dive the plan and it still turns to crap. Unfortunately in deep diving as you clearly know, the risks are high (and I suppose part of the buzz for us, however Murphy lurks for the people who are risk takers). "Bloody Murphy"

Things go bad quickly at depth. At 170 m 18 times faster than at the surface.

I do understand your need to continue diving caves, I couldn't stop diving no matter. Stay safe

 

[jethrocramp]

So he may have passed out while breathing from the long hose? Hyper ventilating, working to hard?? Hmm


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Mike,

In the Salvage section of the piece it says:

Then, we went to check the equipment of Wang Tao:
8/70 Master Cylinder: Remaining 0, HALCYON H75 a head because of the strong collision shell damage, and the card has a lot of rocks, but there is no leakage.
8/70 stage cylinders, remaining 0, normal work
10/65 stage cylinder, 195 bar, working properly
18/45 pressure cylinders, the remaining 120 bar working properly
21/35 pressure cylinders, the remaining 200 bar working properly
EAN 35 pressure cylinders, the remaining 200 bar working properly
EAN 50 pressure cylinders, and the remaining 40 bar (Zhou Pei use), works fine
O2 pressure cylinders, the remaining 200bar working properly.
Clothes inflatable bottle, and the remaining 100 bar
Main lights off, open work properly
Spare lamp normal

I translate the bit about the HALCYON H75 as:

HALCYON H75 first stage with exterior damaged from severe knocks and with stones jammed in it, but not leaking gas.

So Wang Yuan says that it was at about 120m when Wang Tao signalled he was out of air. However from his equipment it looks like he still had a breathable stage cylinder (10/65 with 195 bar MOD of 130m with PO2 of 1.4) available. Wang Yuan described Wang Tao as being calm at this stage. Despite that he seems to have missed that he could have switched gases and as a result he forced them to make a rapid ascent to 75m sharing Wang Yuan's limited back gas. During that ascent something happened to Wang Tao and he floated off free from the long hose.

Either way it looks likely that a key step on the way to his death was not using gas that was available to him.

---------- Post added May 6th, 2014 at 05:33 PM ----------

"deep stage using BULHMAN form, the latter half of decompression using the bubble theory"

That seems backwards, but it's probably a translation issue.

The original

减压计划： 从84米开始进行阶段减压，深的阶段使用BULHMAN 表格，后半段减压采用气泡理论

reads:

Decompression plan: From 84m start staged decompression., for the deep stage use BULHMAN tables, for the second half of the decompression use bubble theory

So the translation is correct.

 

[Mike.D]

Oh man..... He had a stage on him yet went to his buddy for air?? I just can't get my head around that. Properly trained, experienced divers on a dive out of their experience levels and it goes wrong so close to the end......


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[jale]

So sad
Here is the version from the rescue team:
https://www.facebook.com/media/set/?set=a.1408025219471944.1073741882.1382194778721655&type=1
We have to note that it is rare to have such an analysis done. This is impressive. A lesson for all of us...

 

[chillyinCanada]

Geee eeezzżz.

I've some questions but my hope is people more experienced and educated will help with that as the thread goes on, is analyzed, criticized and everything good and bad that sadly comes from posters in these kinds of threads.

One question I will ask now: these divers had had at least 15 previous dive accidents or am I misunderstanding those notations? Please eeducate me as to what that notstion means. Thanks.

I'm so sorry to read this and to think of what the divers experienced.

 

[Jan Kruger]

I would like to send you my condolences for losing your best friend in such a sad way.
I feel you tried your best to sort out this serious problem at depth : firstly finding the lost guide line quickly to ensure you will find your way out. Then handing your buddy your long hose fully knowing there is a good chance you are going to be short of gas before you get to your gas station at 75 meters. Now you also went up much quicker than normally to try and get to the next gas station.

When your buddy drifted away you tried to reach him by grabbing for him. You could not let go of the guideline because of your low air/bad vis situation at depth.
When you had been to the gas station you went down to 90 meters looking for your buddy.

No I commend you for really trying to save your buddy.

I also want to congratulate your support diver Zhou Pei . He probably saved your life several times by helping you down deeper to decompress in several stages , made sure you stayed awake and conscious . While you were vomiting and had seizures he kept you going. Well done to him.


Thank you for relating the actual story...not some speculation from some newspaper. I hope you will keep on diving and that you will get closure after losing your best friend in such a tragic way.

 

[ajduplessis]

It seems that Tao was delayed, ran out of gas (it goes quick at those depths) and Yuan donated the long hose. They made way to their stages, switched, and Tao exhausted the stage then drowned having no other gas supply.

That's my interpretation. Its a LOT of text to go through, and the translation makes it tough to understand.

Sounds about right.