Scary incident. Escaped death but had a DCS hit.

I am sharing this for accident analysis purpose, as there may be more lessons to be learnt then what I am stating.

I am an advanced open water diver but I don't have a lot of experience. This was my 7th dive after getting my AOW. Since I was new, I got paired up with an experienced diver with around 200 dives. She was a very competent diver, who was very familiar with the dive site that we were diving. Max depth was 120 but she told me that good things are at a 100' so we will be at that depth. She said that if you follow me closely I will be able to show you some interesting things.

We descended and the bottom was a shallow slope that would get flattened at 120 but at that depth it was all sand. I was swimming behind her and she would stop to point out small marine life that you would normally not pay attention to. All of a sudden, she shook me and gestured to look behind. Behind me was a huge turtle. I was excited to see it because I for some reason thought that they stay in the shallows so that they can come on land but this one was swimming towards the sand bed.

So both of us swam towards the turtle to see it up close and we continued to watch it until it was gone. I checked depth and we were 120 because we had swam down the slope. I checked my air and was like OH $HIT! I was really low.

Later investigation revealed that all my previous dives had been on a big steel tank because I was a heavy breather. These dives gave me an estimate of how long my tank would last. On this dive I was diving a tank that is ranked as AL80. I did not know the tank capacities because to me they are all "scuba tanks." Secondly we had swam hard at the turtle, deviated from the plan and spent time at 120 where I was catching my breath. All this meant that I was dangerously low like any minute low.

I swam to my dive buddy and showed her my gauge and she was had that "HOLY F@#CK" look on her face. She did not have an octo but the Air2 which is connected to her BCD. She took that in her mouth and gave me her reg. The length of the main hose (I am guessing 25 to 30 inches???) does not allow you to put a lot of distance between you and your buddy so we were pretty face to face. This may be okay to go straight up but we had to swim back to the anchor line and go up the anchor line. The bottom was calm but as you go up the current would get stronger and stronger so in the dive briefing we were told that if you do not come up the anchor line and make a free ascent then you will surface far far away from the boat. She decided that she had enough air for both of us to swim back to the anchor line and go up while air sharing.

We started to swim back but it is difficult to do that while air sharing with a hose that is so short. So on the way back the mouth piece of the second stage got disconnected and I ended up taking in a big gulp of sea water. She did not immediately realize that the mouth piece was not on the regulator anymore and was offering me the same reg again. I coughed and started to choke on that mouthful of water and after that, I thought I need to shoot up. I started swimming up as fast as I could while she followed me with a regulator that did not have a mouth piece on it.

I did not think about exhaling because in such a mess, you go to instincts and your instinct is to keep maximum air in your lungs so that you can make it up to the surface without running out of air. So I was making an ascent from about 90 to surface on a breath hold. Fortunately, the sea water I had swallowed was making me cough all the way up. These coughs were making me exhale out the air in bursts. I do not have any memory of time because your mind sort of shuts down when you deny yourself breath. All I remember is that I was in a state of blindness telling myself if I inhale I will die here. I am nut sure if my eyes were closed or if I could not see anything. Then I lost consciousness for a moment like total black out and no sense of awareness and came back to my senses on the surface coughing water violently. In my mind I was still swimming upwards and broke my breath before reaching the surface so while coughing I was still trying to go up but there was no where "up" to go and that was causing me to panic on the surface.

I was totally disoriented while coughing and it took me sometime to realize that I can breathe and I am not drowning. My dive buddy was next to me. She had inflated my BCD and was saying something to me that I could not make sense of. Then she started screaming really loud and I was thinking who is she screaming at??? She was trying to call the boat but boat was far and we were drifting away. But I had come to full senses now but still coughing occasionally.

I looked at her and she was looking visibly sick and scared. She asked me if I was okay and I told her I was fine. I asked her the same and she said "I don't know. " Then the boat came and I got on the boat feeling very tired. They gave me the field exam and I was lethargic but nothing more. She on the other hand was really sick. She was having a very hard time sitting up straight and insisted that she would take the neurological exam laying down flat. They were asking her to sit up and she was acting irrational and agitated insisting that she is fully capable of doing the whole exam laying down. When she would lay down, she would talk nonsense.

They put us both on oxygen and brought us back. It turned out that her and I had both experienced a DCS hit with temporary symptoms. We were both tired but she was way more than I was. Her symptoms lingered on longer but gradually subsided and she is fine now.

We were both checked by the same hyperbaric physician. He said that I do not have lung damage because I coughed a few times all the way up. Had I not been coughing my way up then this would be serious. While lung expansion was avoided, rapid ascent caused what he calls decompression stress or a mild DCS hit.

My dive buddy had chased me trying to keep up so she had subjected herself to the same ascent rate. The only difference was that her symptoms were more severe and took a bit longer to go away but he did not expect any long term damage in either of us.

The moral of the story is:

a) Air2: This is a very unsafe device and when things go wrong, it forces divers to adapt a style of diving that is never covered in any of their training. Please get rid of this ASAP!

2) Advanced Open Water certification is not a comprehensive course. It does not have tank size comparisons and which tank will last how long with your breathing rate etc.