Lucky guy...

[Dirty-Dog]

So I was talking to a friend tonight. Now I'm annoyed.
He is a PADI OW diver with 10-12 dives logged, all of which have been either pool dives or short shallow dives in the local res. He recently decided to purse PADI AOW training through a LDS. Like other shops in this area, they do their OW sessions at the Blue Hole in New Mexico. I asked him tonight how his class was going...
He tells me that he hasn't completed it because he was sick after the first dive. I asked for details. Apparently, the first dive was to 80FFW (that's pretty much rock bottom in the Blue Hole). Their bottom time was 31 minutes. Of course, the altitude means this should be considered a 100' dive, and that is, in fact, how his dive computer (a Suunto Stinger that I sold him) treated it. After 31 minutes (which I'm sure readers are all aware is about 11 minutes past the NDL for a 100' dive...) they ascended. He did follow the computers instructions, doing three 3-minute stops on the way up.
After this, he tells me that he had body aches, a headache, nausea, and felt confused.
"Congratulations, (name). You got bent."
The problems I see with this dive:
1 - "Trust me" dive. He says that he now realises he should never have stayed down, but as a new diver he admits that he thought "he's an instructor, he won't steer me wrong...".

2 - He told the instructor about his symptoms. Not only did nobody recognise them as being a problem, the instructor asked him if he was going to go on the second dive.

I've encouraged him to
A - not take any classes from this shop
B - contact PADI to report the standards violation
C - review his course material from OW, especially those sections concerning safety...

It's been 10 days, so he's well out of the window for any treatment, and he's fine now, but that's only because of luck.

 

[Diver0001]

I'd like to hear the other side of this story too.

He was busy with AOW and one of the required components of AOW is at least one deep dive. I presume this is the dive they were doing and 80ft is not an uncommon depth to achieve during this dive.

As you know, bottom time is the time from the beginning of the decent to the beginning of the ascent. A computer like the stinger doesn't show bottom time, however. It shows dive time, which is the time from the beginning of the decent to the point at which they surfaced. Depending on bottom topography and their navigation plan it is possible that they didn't spend 31 minutes on the bottom. In fact, it is unlikely for them to have done so. In my experience most new divers using (I presume) an AL80 *couldn't* spend 31 minutes at 80ft and then still have enough time for the decent to that depth and an ascent to the safety stop etc.

In the case of going 11 minutes over deco at that depth the diver would also have 20-30 min of stops, which would make his run time about 50-60 minutes (give or take, I don't have access to planning software right now so this is shooting from the hip). The point being that I suspect a miscommunication and that he was telling you that the total dive time and not the bottom time was 31 minutes. It would be interesting to review his profile, gear and gas choices, etc. and to see if the computer did in fact go into deco mode.

Finally, It's clear that he didn't feel well after the dive, but the symptoms you mentioned can be symptoms of many different things. It doesn't follow directly from his symptoms that he has a decompression sickness, at least not to me. Morever, if he *had* been in deco mode and he had followed the ascent that the computer indicated (while usually sub-optimal) he still very likely wouldn't be bent.

So from where I'm sitting, I think there's more happening here. I think if we knew the other side of the story we may draw different conclusions.

R..

 

[Dirty-Dog]

I'd like to hear the other side of this story too.

He was busy with AOW and one of the required components of AOW is at least one deep dive. I presume this is the dive they were doing and 80ft is not an uncommon depth to achieve during this dive.

As you know, bottom time is the time from the beginning of the decent to the beginning of the ascent. A computer like the stinger doesn't show bottom time, however. It shows dive time, which is the time from the beginning of the decent to the point at which they surfaced. Depending on bottom topography and their navigation plan it is possible that they didn't spend 31 minutes on the bottom. In fact, it is unlikely for them to have done so. In my experience most new divers using (I presume) an AL80 *couldn't* spend 31 minutes at 80ft and then still have enough time for the decent to that depth and an ascent to the safety stop etc.

I asked about that. They were on AL100s, and he surfaced with about 250PSI. The good news here is that he's got a pretty good SAC rate.

In the case of going 11 minutes over deco at that depth the diver would also have 20-30 min of stops, which would make his run time about 50-60 minutes (give or take, I don't have access to planning software right now so this is shooting from the hip). The point being that I suspect a miscommunication and that he was telling you that the total dive time and not the bottom time was 31 minutes. It would be interesting to review his profile, gear and gas choices, etc. and to see if the computer did in fact go into deco mode.

There is no profile. The Blue Hole in NM is literally that; a hole. Think of it as an 80' deep swimming pool and you'll be pretty close to correct. Jump in, descend, (there's a platform for OW divers and the bottom for AOW) and you're done. I specifically asked if he meant run time or bottom time. They started their ascent at 31 minutes, with three 3 minute stops on the way up.

Finally, It's clear that he didn't feel well after the dive, but the symptoms you mentioned can be symptoms of many different things. It doesn't follow directly from his symptoms that he has a decompression sickness, at least not to me. Morever, if he *had* been in deco mode and he had followed the ascent that the computer indicated (while usually sub-optimal) he still very likely wouldn't be bent.

When I sold him the Stinger, I spent a fair bit of time with him going through the manual. It was in deco. If he showed up in our ER with the same story, he'd be sent to the chamber.

So from where I'm sitting, I think there's more happening here. I think if we knew the other side of the story we may draw different conclusions.

R..

Turns out the instructor is a brand new relocate from California. I suspect he neglected to consider the altitude. This dive wouldn't have been a deco dive at sea level.

 

[Diver0001]

Were they air? On 32% it wouldn't have been a deco dive either.

All I can do, obviously, is speculate but I have trouble believing that even if the instructor had forgotten about the altitude that

a) his own computer wouldn't have gone into deco mode when the students' had.
b) none of the students would have indicated that they were approaching the NDL and/or they would have allowed themselves to incur 20 to 30 minutes of required stops without indicating that they had an issue.

I don't want to discredit you but I'm having a really hard time understanding how something like this could have happened in the way it was described.

R..

---------- Post added June 2nd, 2014 at 11:19 AM ----------

They started their ascent at 31 minutes, with three 3 minute stops on the way up.

Just wanted to zoom in on this detail. If the dive had happened as described then the last 2 stops (6 and 3 metres) would have been a combined total of 15 to 20 minutes (I think). Doing 3 minute stops would have put the stinger into error mode for 48 hours. Was it in error mode when you saw it?

For the AOW deep dive there is a "required" 3 minute stop. Namely the safety stop. The standard dictates that you cannot skip this stop even if it's not strictly required. Is it possible that the instructor put so much emphasis on this that the students thought it was a required deco stop?

R..

 

[Dirty-Dog]

Were they air? On 32% it wouldn't have been a deco dive either.

They were on air; he's not trained for anything else. I thought I mentioned that specifically, but apparently not.

All I can do, obviously, is speculate but I have trouble believing that even if the instructor had forgotten about the altitude that

a) his own computer wouldn't have gone into deco mode when the students' had.
b) none of the students would have indicated that they were approaching the NDL and/or they would have allowed themselves to incur 20 to 30 minutes of required stops without indicating that they had an issue.

I don't want to discredit you but I'm having a really hard time understanding how something like this could have happened in the way it was described.

R..

I had a problem with it too, which is why I questioned him at length. He reports that he did show his computer to the instructor, he says twice, and was given the "OK" signal.


---------- Post added June 2nd, 2014 at 11:19 AM ----------

Just wanted to zoom in on this detail. If the dive had happened as described then the last 2 stops (6 and 3 metres) would have been a combined total of 15 to 20 minutes (I think). Doing 3 minute stops would have put the stinger into error mode for 48 hours. Was it in error mode when you saw it?

I didn't see him until 10 days after the class, so I can't say. I can only repeat what I said earlier; he recognised the deco instructions from the stinger and says it required 3 different 3 minute stops.

For the AOW deep dive there is a "required" 3 minute stop. Namely the safety stop. The standard dictates that you cannot skip this stop even if it's not strictly required. Is it possible that the instructor put so much emphasis on this that the students thought it was a required deco stop?

R..

A safety stop IS a deco stop, of course. But you don't normally have your computer telling you to do three of them on the way up.

 

[Agility]

I do not know the stinger, but I also do not know any deco model that comes up with 3 stops of 3 minutes each at 9,6,3m.
I suggest the profile should be downloaded from the DC and analyzed before filing a complaint.

 

[Diver0001]

Very strange.

AFAIK a Stinger is an older model that uses bubble wrapped Buhlmann so it wouldn't show 3, 3 minute stops. It would show 1, 2 and 6 maybe but more likely it would just accumulate 9 minutes of deco at 3-4 metres becuase you have to go WAY the hell over the NDL's with an older Suunto computer before you get a ceiling of 9 metres or deeper (or even 6).

I don't doubt that this is what he told you. You're not someone who is prone to exaggerating. I just wonder if what he saw and the way he interpreted that are the same.

I also can't get my mind around why an instructor would see a student's computer in deco and not respond to that even if his own computer was not. Depending on settings, it's possible to make the Suunto computer accumulate a LOT of deco even when another computer with different settings thinks the dive is ok..... but even at that, if a student showed me his computer and it was in deco mode ... I just can't imagine what could be going through your mind that you would say "ok" and ignore it... or at the very least not debrief it after the dive.

As you said it's possible that the instructor didn't account for the altitude and thought the dive was going according to plan but still.... very strange.

R..

 

[scoobydrew]

OP - why not call the instructor and ask for some info? If you do so then position the call in a light way as opposed to accusatory and just say you were chatting with your buddy and he mentioned a few things that sounded interesting so you wanted to find out more about them. The dive would have to have been the deep dive for it to be in standard and if it was the first dive of the course then the instructor would need to do some kind of pre-assesment before taking the student to depth, this could be an exercise like mask removal and replacement while neutral at 20 feet, this would take time that contributes to the run time but the n2 loading at this depth is far less than at 80 or 100 feet. By the time all unknown students have done their exercises and everyone has cleared sinus issues and buoyancy issues it could easily be over 10 minutes before they hit the bottom.