AOW Deep Dive uncontrolled ascend

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WoodTurner

Registered
Messages
39
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Location
The Netherlands
# of dives
50 - 99
Normally I am not the person that complains, but if there is a lesson to be learned, I don’t mind sharing my experience.

September 25th 2022 Den Osse, The Netherlands.

Though the whole AOW course was of poor quality, the deep dive specialty was terrible and could have gone sideways.

Plan of the dive was to experience effects of nitrogen narcosis at depth by doing simple tasks such as recognizing number order on the wet notes. The group consisted of 4 students, 1 instructor and 2 DM’s (apparently still in training). The number exercise was conducted at the parking lot, each of us was timed how fast we could find all of the numbers in proper order. Signal was given to gear up and walk to the entry point on the shore. Water visibility was poor, at shallow about 2 meters tops. We were split into 2 teams, 2 students and 1 DM with birds eye view, let me name that team A and team B. Instructor was in the lead and teams followed, me, my buddy and DM (team B) were behind team A.

Swim to the designated depth was nice and slow, it took us about 16 minutes to get to 24m depth, visibility there was even worse, about 0,5-1m. All of the students dropped on the lake floor, silting up and making visibility closing to zero. In order to see the wet notes I used my primary torch, next to the poor visibility, the lake is pitch dark at that depth.

After successfully completing the exercise, a signal was given to swim further. Team A led by the instructor was gone and within a few seconds we couldn’t see them anymore due to poor visibility. I gave a rough direction to my buddy, as he looked confused, showing with body language, kind of, where is everyone? Our DM was also nowhere to be found, and I made sure my buddy was close to me and we swam the direction I thought team A went. At some point, our DM joined us from nowhere, and he also seemed confused with the situation. He was indicating that he doesn’t know where team A is, and was asking me whether I knew. In the corner of my eye I saw the flash light, and thought that must be team A, so I again indicated the direction and we continued swimming trying to catch the group with the light. After a brief moment I realised the group was diving doubles, and unfortunately were not team A. My buddy and DM were confused, as far as I could decipher their body language they didn’t know what to do next. I did try to give a hand signal to the DM, what to do now, he just shook his shoulders “I don’t know”.

I’m not sure how much gas I used by that point, and feeling confused myself, feeling task loaded, I started losing my buoyancy control. I started ascending quite fast, trying to deflate BCD and my dry suit simultaneously, but without success. My eardrums were vibrating like crazy and next to trying to deflate my buoyancy equipment all I could think of was, exhale, exhale…

I was at the surface, feeling extreme disappointment in myself not being able to control the situation I’ve found myself in. The shore was about 60-70 meters and I decided to swim slowly on my back and get out the water, observing the surface and waiting for my complete group to come out. I’m not sure how long the swim took, but I came out, and waited another 10 minutes before I could see my group surfacing. At that time, I suppose the instructor figured she was missing the diver, and they were all looking opposite of the shore and waiting for me to surface. That continued for 5-10 minutes, when the instructor finally looked at shore, I waved at them and they started swimming towards me. Group was relieved they didn’t lose me, especially the DM, he was really concerned about my wellbeing, asking me constantly if I’m okay…. I just wanted to be left alone, after being disappointed in myself, I was disappointed in the group as well, because of lack of awareness and the lost diver procedure wasn’t followed. Instructor though, never said anything.

After a while we gathered and I felt I needed to speak up, I told them I’m angry with myself for ascending too fast, but I’m also disappointed at the group as we’ve failed as a team to recognize potential incidents and react accordingly.

This was my dive number 15, and only 8th after 11 years of not diving.

In the attached dive log profile, you can clearly see my buoyancy issues started from 24th minute, and rapid ascend from 25,5 minute.

1675531570868.png
 
Thanks for sharing. That sounds bad on so many levels. Are you OK after all this? Physically, I mean?
 
Dont be too tough on yourself. You knowingly went diving in a low vis environment. The team lost contact with each other, you surfaced and although you ascended too quickly you made yourself safe. You being upset with yourself means you know what you did wrong and most likely know you can do better. Your comment of "I’m not sure how much gas I used by that point" is more of an issue (for me). Set a time for you to check air/gas levels. Perhaps the time should have been every 5 minutes at that dept. How much air have i used in 5 minutes - then if you have consumed 300 lBS in 5 minutes then I should have consumed 600 LGS when I check at the 10 minute mark. Adjust your consumption as you continue to check. What is it at 10 minutes and what should it be ar 20 minutes. Or perhaps you can predict that i will be at my turn pressure at 18 minutes. You can decide to go to the surface anytime in low/poor vis but running to out air/gas in poor vis could be a huge problem.
 
Did you and your team, including the instructor and DMs, agree on a dive plan that includes lost buddy plan, gas turn around pressure, compass bearings, path of the dive, emergency procedures, max depth of the dive, max time, etc.? How did you know you were coming up fast? Did you have a dive computer/digital gauge on you?
 
Don’t be too disappointed.

Something similar happened to me during AOW.

Albeit uncontrolled, you managed to surface safely. You can improve your buoyancy control by practicing dumping and ascending very slowly.

From my limited experience, people new to drysuits do not dump gas from their drysuit early enough: they wait too late before dumping, when they are already ascending with a bit of speed. You want to feel when you start being floaty and think whether you need to dump a bit then.

Like @Norwegian Cave Diver said, try to keep an eye on your SPG every 5-7 mins, that will help you to have more awareness about when to ascend.
 
I glad you were not injured.
However....
Your instructor violated standards, thus her competency is questionable.
(1) The timed task at depth disappeared from the PADI AOW Deep Dive #curriculum in 2009, and was replaced by looking at colors at depth. The timed task is not done until dive #3 of the full Deep specialty course.
(2) The instructor must be in direct supervision of all the student divers at all times. On the deep dive, this cannot be delegated to certified assistants. And, if your DMs were in training, they were not even certified assistants. Your dive plan violated the requirement for direct supervision, and the execution of the plan was worse.
Frankly, you ought to ask for your money back and complain to PADI.
(I assume PADI, since you refer to AOW.)
 
The good news is that your ascent rate is not that bad, still fast but it shows you were either properly weighted or managed to vent some gas.
Mistakes happen, as your instructor proved by getting his certification.


The dive you tdescribe shows a lack of situational awareness, regard for safety and any sane agency standards.
My suggestion would be to change the instructor.
 
Thanks for sharing. That sounds bad on so many levels. Are you OK after all this? Physically, I mean?
I'm fine Cheizz, thanks for asking. 2 hours after the first dive, and after I cooled down, we went for second dive, which was rather uneventful and I don't remember it clearly, but it went well (logbook).
 
I'm fine Cheizz, thanks for asking. 2 hours after the first dive, and after I cooled down, we went for second dive, which was rather uneventful and I don't remember it clearly, but it went well (logbook).
Was the deep dive the first dive of the AOW class?
 
Dont be too tough on yourself. You knowingly went diving in a low vis environment. The team lost contact with each other, you surfaced and although you ascended too quickly you made yourself safe. You being upset with yourself means you know what you did wrong and most likely know you can do better. Your comment of "I’m not sure how much gas I used by that point" is more of an issue (for me). Set a time for you to check air/gas levels. Perhaps the time should have been every 5 minutes at that dept. How much air have i used in 5 minutes - then if you have consumed 300 lBS in 5 minutes then I should have consumed 600 LGS when I check at the 10 minute mark. Adjust your consumption as you continue to check. What is it at 10 minutes and what should it be ar 20 minutes. Or perhaps you can predict that i will be at my turn pressure at 18 minutes. You can decide to go to the surface anytime in low/poor vis but running to out air/gas in poor vis could be a huge problem.

Thanks for the kind words NCD!

To be honest, I don't remember, what I do know is that I'm more meticulous about my gear, trim, streamlining, gas usage, then the people I dove with lately. I do check my SPG regularly, but don't remember whether I checked it during the event (losing instructor group, the DM etc.). In my log, I was on the surface with 70 bar left in the 10L cylinder, I'd guess I was at 80 or less when the buoyancy problems started.
 

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