Try Scuba Accident..what happens next?

[Zef]

The instructor's account of the events (Spanish, auto-translated to English via FB), posts #18-19, is in this thread. Here's my brief summary pulling from that account:

- 40 minute class explaining diving theory, diving practices and equipment
- equipment setup by instructor, but had divers open tank, do safety checks under his supervision
- two DSD's and one OW
- after buddy check, divers went down to 1.5m and did exercises (likely mask clearing, regulator purging, etc.?)
- first dive went well
- instruction reiterated during surface interval
- second dive was 36 min
- at 14 min, 4m, Rocio (woman in incident) signed she wanted to go up. Instructor asked her why and she indicated she was having a laughing fit and he signed back it was okay to laugh into regulator and asked if she wanted to cancel (since they were next to the boat) or continue to follow. She indicated she wanted to follow.
- all three divers had 110 bar, so nothing to indicate one diver was more distressed than the other
- dive was by a buoy with max depth of 9m
- dive continued for 18 min, going away from the buoy
- upon return to the buoy, instructor asks divers if they're okay and the respond yes
- instructor looks for boat and when he turns around, Rocio is missing
- instructor asks other students if they've seen her and they indicate no
- instructor takes other students on reverse course and is unable to find Rocio, so surfaces with remaining two students
- instructor tells boat he's missing a diver and asks if they've seen bubble trails
- boat points out to a bubble trail and he descends again to search, but finds it's not her
- upon surfacing, he finds Rocio being brought to the boat by a colleague who had found her with mask on and no regulator in her mouth at 6m
- O2 administered, Koh Tao Rescue contacted, and two client divers on the boat were doctors helped in the emergency

- instructor followed Rocio from Koh Tao, to Koh Samui, to Bangkok
- instructor, two accompanying divers, and others from the dive op gave accounts to police (It would be nice to see these accounts.)
- instructor contacted consulate and family

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I'm only AOW, so I don't teach, but I know what you're saying.

Hmmm...so assuming they started with 200 bar in their tanks, at 14minutes they were down to 110 bar, that means in 14 minutes they used 90 bar of air.

Given that the dive was 32 minutes long in the synopsis list you posted....that means that given their air consumption during the next 14 minutes had they stayed at the same depth (4 meters) they would have used another 90 bar...which would only leave them with 20 bar in the tank had they surfaced at the 28 minute mark but they were under water for another full 4 minutes and descended to a deeper depth (9m) which means their consumption increased. If they started the dive with less than 200 bar in their tank they would have been out of air before reaching the surface...perhaps this is what happened to Rocio....if the standard protocol is to arrive at the surface with between 30 and 50 bar in ones tank (normally dive operators brief to surface with 50 bar), then the dive was mismanaged from the start and the dive instructor really f*&ed up....despite a 40 minute class explaining dive theory, the instructor himself was not managing his clients air properly from the description you have given. The more you post the more it seems like this death could have been avoided and the more the instructor seems culpable. You are not painting a good picture of this instructor....physics doesn't lie.

Maybe my calculation is off, correct me where I am mistaken
200 bar tank
110 bar indicated on SPG at 14min mark = 90 bar consumed in 14min (at 4m depth)
90/14 = 6.43 bar/min
6.43 bar x 32min = 205.76 bar consumed = OOA (not even taking into account that they descended to 9m)


-Z

 

[oncor23]

I've seen three types of DSD's: instructor holding divers by the tank valve and dragging the DSD divers around, instructor hand holding the DSD divers, and instructor guiding the DSD divers around, like with certified divers. This is all dependent on how well the instructor has assessed the DSD divers' comfort in the water. I have seen DSD divers that are as good as certified divers because they've gotten some instruction somewhere/sometime but do not have the certification.

In this particular incident, the DSD divers were on their second dive and it does not sound like they were hand held, which leads to the conclusion that they were somewhat comfortable in the water.

Even if the instructor is convinced that his/her students are comfortable in the water, that comfort level could change in an instant...the moment anything goes wrong. The instructor needs to keep track of all the students so help can be provided very quickly.

I mostly go on diving trips on my own, which means I get assigned instabuddies. I take my buddy duties seriously. We're supposed to look out for each other. I try to assess my buddy's experience by asking some general questions. Once in the water, some of these buddies just swim off in some random direction, away from the guide. If something were to happen, is it my fault? Is it the guide's fault? Should diving be more restrictive for safety... one guide and one diver?

For this incident, we don't have all the information, like what did other divers around the area notice? Especially the two other DSD divers. How did three people lose track of one person?

For environmental conditions, bays in Koh Tao may start fairly empty if the boat arrives early, but an hour later, there could be several boats and many more divers in the water. Everyone looks very similar underwater. It's very easy to get caught up in the wrong dive group. I've witnessed it (see an earlier post). Perhaps instructors should keep extra watch when this occurs and perhaps this particular instructor made a huge fatal mistake by being too comfortable with his DSD divers.

Instabuddies are or should be certified divers. If they don't follow the guide, that is their choice. If the guide doesn't feel the need to keep his divers in line, then you shouldn't either. One topic of conversation for your predive discussion with your guide is whether you need to follow him/her on the dive. Once the importance of sticking with the guide is determined, then you can discuss how closely to follow the guide with your instabuddy. If the instabuddy and you agree to follow the guide before the start of the dive and then they swim off on their own...that's on them. But again, they are a certified diver. So are you.

On this incident there was one other DSD diver and one certified diver, besides the victim and the instructor. The instructor should have made it clear to the certified diver that the other two participants were DSD. The instructor could have asked the certified diver to help keep an eye on the DSD divers. The instructor should have insisted that all the divers stay within sight of him. The instructor should have been aware that other divers might be in the area they were diving and reminded his group of some distinguishing feature he had so they could pick him out...and determine some feature on his students to help him pick them out. Again...if the instructor knew there would be other divers in the water, that is one more reason for the instructor to insist that his DSD divers stay close to him so they didn't get confused and lost. ​

 

[oncor23]

I did a DSD class a decade ago in Hawaii. We had a classroom session. Then an hour long pool session on scuba. All exercises etc were done in the pool session. After lunch we did a shore dive. There was 1 instructor, there was 1 student (me), and 1 experienced New York I know what I am doing since I dive rivers diver. NY was a total cluster. Instructor was next to me in awesome viz. Great experience and hooked me on scuba.

The New York river divers I know have their "stuff' together because the Niagara and St. Lawrence Rivers are big waters with plenty of current. Of course, that doesn't mean there aren't some NY divers who would constitute a cluster, but I guess I fail to see how identifying NY divers was important to the topic.

 

[divinh]

Hmmm...so assuming they started with 200 bar in their tanks, at 14minutes they were down to 110 bar, that means in 14 minutes they used 90 bar of air.

Given that the dive was 32 minutes long in the synopsis list you posted....that means that given their air consumption during the next 14 minutes had they stayed at the same depth (4 meters) they would have used another 90 bar...which would only leave them with 20 bar in the tank had they surfaced at the 28 minute mark but they were under water for another full 4 minutes and descended to a deeper depth (9m) which means their consumption increased. If they started the dive with less than 200 bar in their tank they would have been out of air before reaching the surface...perhaps this is what happened to Rocio....if the standard protocol is to arrive at the surface with between 30 and 50 bar in ones tank (normally dive operators brief to surface with 50 bar), then the dive was mismanaged from the start and the dive instructor really f*&ed up....despite a 40 minute class explaining dive theory, the instructor himself was not managing his clients air properly from the description you have given. The more you post the more it seems like this death could have been avoided and the more the instructor seems culpable. You are not painting a good picture of this instructor....physics doesn't lie.

Maybe my calculation is off, correct me where I am mistaken
200 bar tank
110 bar indicated on SPG at 14min mark = 90 bar consumed in 14min (at 4m depth)
90/14 = 6.43 bar/min
6.43 bar x 32min = 205.76 bar consumed = OOA (not even taking into account that they descended to 9m)

The dive profile hasn't been posted. We don't know the starting starting pressures. Air consumption isn't a constant, as you're presenting it. The max depth in the area is 9m, not that they descended to 9m. They were at 110 bar before continuing the dive for another 18 minutes, not that they were at 110 bar at 14 min. The entire dive was 36 minutes, including search time. At the time the air was requested by the instructor, all three divers were consuming at the same rate, thus the 110 bar signaled by all three divers. The two surviving divers would have faced the same OOA situation as Rocio, but they had enough air to reverse track for a quick search and then surface.

Posts #18 and #19 are there for you to read.

 

[Steve_C]

but I guess I fail to see how identifying NY divers was important to the topic.

It was not important to the topic. That the diver was not a DSD was relevant to class size. That the diver was a bit of a cluster was relevant in that the instructor stayed with me and let the other diver swim on the surface when he ran out of air while I still had plenty. NY diver was what the other diver made a point of calling himself.

In no way was that meant as a dig at NY Divers. As you note there are many great ones. I have dove with several and was originally taught by one. It was a bit of a side dig at a particular boastful person who assumed they knew it all especially when diving in conditions they were not used to. Maybe putting it in quotes would have made that clearer.

 

[Zef]

The dive profile hasn't been posted. We don't know the starting starting pressures. Air consumption isn't a constant, as you're presenting it. The max depth in the area is 9m, not that they descended to 9m. They were at 110 bar before continuing the dive for another 18 minutes, not that they were at 110 bar at 14 min. The entire dive was 36 minutes, including search time. At the time the air was requested by the instructor, all three divers were consuming at the same rate, thus the 110 bar signaled by all three divers. The two surviving divers would have faced the same OOA situation as Rocio, but they had enough air to reverse track for a quick search and then surface.

Posts #18 and #19 are there for you to read.

Oh my mistake. I calculated 32 minutes....lets correct that. And lets remove depth from the equation:

Lets also calculate this for different starting pressures:

300 bar tank
36 minutes total dive time: 18 minutes of diving after air check = 18 min past at air check
110 bar indicated at air check = 190 bar consumed
190 bar / 18min = 10.56 bar/min
10.56 bar X 36 min = 380 Bar consumed = OOA

234 bar tank
36 minutes total dive time: 18 minutes of diving after air check = 18 min past at air check
110 bar indicated at air check = 124 bar consumed
124 bar / 18 min = 6.89 bar/min
6.89 bar x 36 min = 248 Bar consumed = OOA

200 bar tank
36 minutes total dive time: 18 minutes of diving after air check = 18 min past at air check
110 bar indicated at air check = 90 bar consumed
90 bar / 18 min = 5 bar/min
5 bar x 36 min = 180 Bar consumed = 20 Bar reserve to surface with.

So the best case scenario has them arriving at the surface with 20 Bar.

Had Rocio started to panic, swam against a current, or increased her air consumption for any reason she would have breathed through that reserve fairly quickly as she would have had only 4 minutes of air left IF her breathing rate did not change. The instructor states in post 18 that Rocio was lost for 3-5 minutes...that would be enough for her to use up the last of her air supply. Based on my best guess, by the statement of the instructor that she was found at 6 meters with her regulator in her mouth, the sad likelihood is that she ran out of air and drowned.

How you can think the instructor is not culpable in this scenario, losing a student, and not managing the air of clients, is beyond my comprehension.

-Z

 

[divinh]

Even if the instructor is convinced that his/her students are comfortable in the water, that comfort level could change in an instant...the moment anything goes wrong. The instructor needs to keep track of all the students so help can be provided very quickly.
​

​

Even if the instructor is fully aware of his/her students, what happens when more than one panics? He/she would be overwhelmed, yes? In this case, it was one instructor with two DSD divers and one OW. Perhaps only one-on-one DSD's should be allowed? It's the best safety measure.

Instabuddies are or should be certified divers. If they don't follow the guide, that is their choice. If the guide doesn't feel the need to keep his divers in line, then you shouldn't either. One topic of conversation for your predive discussion with your guide is whether you need to follow him/her on the dive. Once the importance of sticking with the guide is determined, then you can discuss how closely to follow the guide with your instabuddy. If the instabuddy and you agree to follow the guide before the start of the dive and then they swim off on their own...that's on them. But again, they are a certified diver. So are you.

Do you think if there was a fatality with the instabuddy that I could say, "Well, he/she swam off. It's not on me." Would that suffice? Or would I be questioned for "abandoning" my buddy? When something goes wrong, everyone is going to be questioned for their decision making, especially by those who paint the situation as someone else's fault, not the victim, as that's victim blaming.

On this incident there was one other DSD diver and one certified diver, besides the victim and the instructor. The instructor should have made it clear to the certified diver that the other two participants were DSD. The instructor could have asked the certified diver to help keep an eye on the DSD divers. The instructor should have insisted that all the divers stay within sight of him. The instructor should have been aware that other divers might be in the area they were diving and reminded his group of some distinguishing feature he had so they could pick him out...and determine some feature on his students to help him pick them out. Again...if the instructor knew there would be other divers in the water, that is one more reason for the instructor to insist that his DSD divers stay close to him so they didn't get confused and lost.

​

All these things you suggested could have happened. Testimony from the other divers on the boat would have revealed these details. The instructor said he only looked away for a few seconds to get his bearings and neither he nor the other two divers with him knew what happened to Rocio.

 

[divinh]

Oh my mistake. I calculated 32 minutes....lets correct that. And lets remove depth from the equation:

Lets also calculate this for different starting pressures:

300 bar tank
36 minutes total dive time: 18 minutes of diving after air check = 18 min past at air check
110 bar indicated at air check = 190 bar consumed
190 bar / 18min = 10.56 bar/min
10.56 bar X 36 min = 380 Bar consumed = OOA

234 bar tank
36 minutes total dive time: 18 minutes of diving after air check = 18 min past at air check
110 bar indicated at air check = 124 bar consumed
124 bar / 18 min = 6.89 bar/min
6.89 bar x 36 min = 248 Bar consumed = OOA

200 bar tank
36 minutes total dive time: 18 minutes of diving after air check = 18 min past at air check
110 bar indicated at air check = 90 bar consumed
90 bar / 18 min = 5 bar/min
5 bar x 36 min = 180 Bar consumed = 20 Bar reserve to surface with.

So the best case scenario has them arriving at the surface with 20 Bar.

Had Rocio started to panic, swam against a current, or increased her air consumption for any reason she would have breathed through that reserve fairly quickly as she would have had only 4 minutes of air left IF her breathing rate did not change. Based on my best guess, the likelyhood is that she ran out of air and drowned.

How you can think the instructor is not culpable in this scenario, losing a student, and not managing the air of clients, is beyond my comprehension.

I very much feel the instructor has some responsibility in the situation. I think he feels very responsible given what he posted, obviously without consultation with a lawyer, who would have likely told him to keep quiet. Perhaps it was the clear his conscience in a self-serving way, but it does say that he has a conscience and is regretful. It does not appear that he was obviously negligent nor set out to put his clients at risk.

As I said, air consumption isn't constant, but even playing with the way you've been calculating...

180 bar tank
36 minutes total dive time: 18 minutes of diving after air check = 18 min past at air check
110 bar indicated at air check = 70 bar consumed
70 bar / 18 min = 3.9 bar/min
3.9 bar x 36 min = 140 Bar consumed = 40 Bar at end of dive.

In my diving from Koh Tao, I've noticed that the cylinder is usually 200 bar on the surface during buddy checks, but upon checking just after entry, it usually reads 180 bar.

 

[Zef]

Do you think if there was a fatality with the instabuddy that I could say, "Well, he/she swam off. It's not on me." Would that suffice? Or would I be questioned for "abandoning" my buddy?

If you had discussed/planned your dive with your buddy before hand and inquired with the guide/dm/instructor if the protocol was to follow them, and your insta-buddy swam off in another direction and you felt it was unsafe to follow them, then certainly you would be correct to NOT follow the insta-buddy, and explaining that situation should/would suffice.

I have been in situations where I have terminated dives and the person I was diving with wanted to continue, I either ascended towards the surface in safe manner or swam to the exit point attaining increasingly shallower depth. The one dive partner that decided to argue about this is no longer a dive partner of mine and I am just chuffed about that. Had this been an insta-buddy the decision would have been even easier. Your first duty is to keep yourself safe....every dive brief, for recreational diving, should include a statement that "anyone can abort the dive for any reason".

-Z​

 

[Zef]

I very much feel the instructor has some responsibility in the situation. I think he feels very responsible given what he posted, obviously without consultation with a lawyer, who would have likely told him to keep quiet. Perhaps it was the clear his conscience in a self-serving way, but it does say that he has a conscience and is regretful. It does not appear that he was obviously negligent nor set out to put his clients at risk.

As I said, air consumption isn't constant, but even playing with the way you've been calculating...

180 bar tank
36 minutes total dive time: 18 minutes of diving after air check = 18 min past at air check
110 bar indicated at air check = 70 bar consumed
70 bar / 18 min = 3.9 bar/min
3.9 bar x 36 min = 140 Bar consumed = 40 Bar at end of dive.

In my diving from Koh Tao, I've noticed that the cylinder is usually 200 bar on the surface during buddy checks, but upon checking just after entry, it usually reads 180 bar.

OK lets take your example as best case...now lets discount the strong possibility that when the instructor had discussed with Rocio on the surface that she could laugh with her regulator in her mouth that she used some of that air to inflate her BC. Also now lets take into consideration that they had dived to 4meters (1.4 ATA)....that would give 28.57 Bar for the end of the dive...now Rocio was found at 6m (1.6 ATA)...that would be 25 bar to end the dive with...that would be 6.4 minutes of air had her breathing rate remained 3.9 bar/min. Again, the fact that she was found unconscious with her regulator in her mouth at 6m is a strong indication of the possibility that she ran out of air and drowned.

The typical protocol for dive centers to brief is that divers should arrive at the surface with 50 bar in their tank. Your example has them 10 bar into that reserve, that is bad gas management. The fact that the instructor lost track of his DSD client in the first place is what makes him culpable....unless he was fending off a shark or attending to another emergency, which he wasn't by his own statements, he should not have lost his client. This was not a "student" in a training course...this was a DSD client. Students do work in confined water and typically have more than 40 minutes of instruction prior to entering open water for their "check out" dives. Rocio was not diving in the context of a prepared student and it was the instructors mistake to not be more mindful of that.

-Z