Two German divers drown at Gran Cenote Kalimba at Tulum

[Big Eyes]

I would like to return to the 47 and 50 minutes: 47 minutes to the stage and 50 minutes to death from the turn of the dive in the 75th minute

The stage was dropped in the 28th minute, according to the report. It is reported in the reports that the two casualties dived slowly and that this distance would normally be covered faster.
Wording from the first official report: "The journey time to the first T-junction was significantly longer than needed, 40 minutes instead of 20 to 25 minutes, and it is likely that the time spent filming, say, 30-35 minutes until the fall of the stage ..... "The stages were placed from the entry Kalimba a bit behind the Boa Restriction, so for the way back a long way in front of the Boa. They dived very slowly on the way there and apparently took twice that time at normal speed. Thus, they would have needed half the time in rapid diving. When swimming for their lives they would probably have been there even faster ....

They shot in the 75th minute. At Jump 1, according to the report, they were in the 99th minute. This results in a difference of 24 minutes, which is deducted from the respective diving times 1. to the stages and 2. to the emergency exit:

Emergency exit: 50 minutes - 24 minutes = 26 minutes
They have swum this route quickly, as the gas consumption has increased visibly. If they had needed twice as much time as at the beginning of the dive, they would have taken 52 minutes to get to the emergency exit, where only diver 2 would have arrived. Probably even longer, as they fought for their survival and certainly at the end as the gas consumption rose, swimming as fast as possible .......

Stages: 47 minutes - 24 minutes = 23 minutes
For this route they needed twice as much on the way there, as written in the report. Thus, they would have had to make that distance to the stages in about 12 minutes if they had taken the swim pace, which is common.

(Bill: 52 minutes - 23 minutes = 29 minutes)
Conclusion: The way to the Stages was about 29 minutes shorter than the emergency exit, if you calculate the same speed for both ways. Assuming that they made the way back from the moment they realized that it is life after death even faster than usual, the time difference between the two goals stage and emergency exit would be even greater than 29 minutes .... ....

 

[Big Eyes]

I made a calculation error:
52 minutes - 12 minutes = 40 minutes difference .......

This results in a difference of at least 40 minutes time difference!

 

[Big Eyes]

The first bill with a time difference of 29 minutes is still correct. I wasted myself in a zealous way.

In the end, however, ultimately it does not matter if it was 29 or 40 minutes longer to the emergency exit than to the stages. The crucial thing is that the way to their stages was much shorter and faster than the emergency exit!

 

[helodriver87]

What is your preferred gas planning in that situation? I've not found a great resource for gas planning differences for straight recreation open water diving.

GUE teaches the minimum gas method. It's designed to account for problem solving on the bottom followed by a slower than ideal ascent from max depth (for the sake of conservatism). It's a function of combined elevated consumption rates, the average depth from max to surface, and a 10ft/min ascent rate. An example for a 100ft dive where each diver is assumed to be breathing at .75 cubic feet/min (elevated stress rate) would look like this:

1.5 (combined air share consumption rate) x 2.5ATA (average depth on ascent in ATA) x 11min (assume 1 min on bottom to donate and slow ascent). This works out to a hair under 42 cubic feet. In a standard AL80, that's basically 1700 psi. So that's the pressure you'd need to leave 100 ft with. You can also work out additional minimums for shallower multilevel segments.

 

[Big Eyes]

@Izze: How do you know that the dive turned around in the 75th minute?

 

[Izze]

@Izze: How do you know that the dive turned around in the 75th minute?

I really wish people would read the report thoroughly before speculating. The math examples are also profoundly wrong. I honestly find it a bit disrespectful not to make sure you have the facts and math right before posting. Your post makes it seem like they made a bad mistake rather than taking a calculated decision.

The turn at 75 minutes is a guess based on video just before and just after that. It says so in the report. It might differ a minute or two but not more.

The distance from the surface to the stages was much shorter than you would expect due to filming. The distance from the stages to jump 1 was not affected by this. Stages to jump 1 is just shy of 20 minutes. I verified this two weeks ago when we dived Calimba.

The time they needed to swim from jump 1 to cenote Ho Tul was exactly 21 minutes. We know this from the logs and the location of the dead divers, so of course that emergency exit did not take 40 minutes longer, or 29 minutes longer or whatever else is claimed.

In reality the stages might have been two or three minutes closer but the passage is also technically more challenging with restrictions and obstacles that complicate gas sharing whereas the emergency exit is a large, flat passage with the flow helping you.

 

[Big Eyes]

Thank you for your prompt reply.

I am sorry that I caused confusion for my previous post. I think that my bill is correct. I just want to understand what happened ..........

So I understand correctly that the turn of the 75th minute is an assumption based on the video immediately before and immediately afterwards.

As far as I know, videos made in the period between the 40th and 81st minute could only be watched on the day of the rescue. After that, three video files were broken (exactly in the period from the 40th to 81st minute). The original SD card is also lost. These videos have disappeared forever and nothing can be detected on what was seen on these files.

I think it's very impressive that you then safely on the basis of the videos assume that the dive has turned in about the 75th minute ..........

 

[Izze]

Thank you for your prompt reply.

I am sorry that I caused confusion for my previous post. I think that my bill is correct. I just want to understand what happened ..........

So I understand correctly that the turn of the 75th minute is an assumption based on the video immediately before and immediately afterwards.

As far as I know, videos made in the period between the 40th and 81st minute could only be watched on the day of the rescue. After that, three video files were broken (exactly in the period from the 40th to 81st minute). The original SD card is also lost. These videos have disappeared forever and nothing can be detected on what was seen on these files.

I think it's very impressive that you then safely on the basis of the videos assume that the dive has turned in about the 75th minute ..........

The time stamps were taken when we watched the video at the police station the day after the accident. All files were available then. Based on that jump 2 was completed around minute 70 and they began taking it back in at minute 80. They had swum at least three minutes after jump 2 (there was a swimming sequence in the video before they come back to jump 2). This allows us to pinpoint the turn with a fair amount of accuracy.

 

[Big Eyes]

I, the wife of Diver 1, who was a very accomplished and theoretically and technically perfect full-cave diver, lost his so beloved hobby on his 1130th dive at Cenote HoTul in Mexico after a 25-year dive experience, I would like to comment here on the comment I disrespectful:
We, the relatives of the deceased have allowed the Foreign Office on 17.11.2018 that the dive computers and video material may be evaluated. We have done this with the utmost confidence in the Mexican police, that sensitive, responsible and confidential dealings with these personal data. On the day after the salvage, there was no approval on our part to evaluate the data! We also allowed the diving quilt to be examined. If we had known that it was not the police, but cave divers who carried everything out, who made this responsible and confidential task, we would never have given our consent!
The fact that such a report is published here on the basis of the confidential data, I find absolutely disrespectful. I am speechless and powerless about this way of dealing with the deaths of two people.

The report concludes from a speculation that the gas planning mistake lies in the last resort: death was caused by a diver error, more to the point of not complying with proper gas planning .... ..........
This is proclaimed here in public of the diving world and the world!

Video files disappear exactly in the area where the cause of the accident must have come. The original SD card disappears to the dive. What is written here for these videos between the 40th and the 81st minute can never be proven again!
The video recordings are interpreted and introduced in such a way that everything fits into the picture, which should be seen.
There are entries in the Weapon (emergency book of my husband), which are partly introduced here. The interpreted as best and it will be omitted the entries that just do not fit into the picture ........

I can not express my indignation and disappointment.

 

[rjack321]

Sorry for your loss @BigEyes but this is accident analysis. @Izze has done an admirable job reconstructing the dive on which your husband died. Is it perfect? No of course not, it's limited to the information at hand and some educated guesses. Could the Mexican police have done this reconstruction? Or any analysis at all? Absolutely not, never in a million years as they don't know the cave at all and aren't even divers.

If you think there was foul play or a crime committed between the 40th and the 81st minute you can take that up with the Mexican police. They only solve about 5 murders in 100 however. Expecting the police to pursue an alternative to the "distracted by filming and they broke gas plans" narrative is extremely unlikely. It's disappointing that you think the evidence is confidential. Even if the video of your husband's last dive wasn't available at all, the basic understanding of the events wouldn't change as the equipment was in working order. Diver error is a leading cause of cave diver deaths, especially in Mexico with shallow depths but maze-like caves.