OOA during open water dives ? It happened to me 4 times... once I knew it would happen, three times it was really "breath taking"...
The first time it happened during my 7th dive, in 1988, at the end of a dive in a local quarry... during that dive I had to demonstrate a rescue of a "victim" from 15m deep, bring him to the surface and tow him towards the entrance of the water... no problem, I did it well... so we went on diving and at the end of the dive my instructor already surfaced and left the water (I know, I know, I know, he should have stayed with me, I know) and I wanted to ascent while practicing a following test, namely ascent from 15m without a regulator... so I threw my reg over my shoulder and started to ascent while slowly exhaling... but it seemed to take ages before surfacing and halfway I ran out of air and I still was at about 7m depth... it turned out the valve and my 1st stage got entangled in a rope and I was stuck at 7m below the wafer, without my reg, without air, without my instructor/buddy... it was a real breath taking experience... literally... and recovering my reg wasn't straightforward since it got entangled as well... eventually I could free myself and surface... and the first thing I did later on that day was running over to the dive shop and purchasing an AirII inflator to ensure I had a redundant air source... So, lessons learned? Make sure you've got a redundant air supply and don't try out "silly things" while you're alone in the water...
The second time was still in the late eighties, during a 40m dive in another quarry... low viz at the bottom of the quarry... at depth I started to have problems breathing, and it seemed that every new breath I got less air and more water in my mouth... after a few more breaths a lot of air bubbles started to escape somewhere at my 2nd stage, so I signalled my buddy to quit the dive and ascent... while ascending more and more bubbles escaped from my reg and the last 10m of my ascent I didn't get any air anymore from my reg and I went all the way to the surface where at that moment the medium pressure hose came loose from my 2nd stage... What had happened? My reg just came back from the annual maintenance and when I went to the dive shop the day before to pick up my reg, the owner of the shop was not in but his wife found my reg and handed it over to me... and apparently the owner of the shop still did not completely finish the maintenance and did not yet fully thighten the medium pressure hose... and that's why during the subsequent dive it came loose... Lessons learned? Simply avoid bringing your reg to the shop when it is not really needed, if everything is working all right there is more risk to make things worse than to make things better... so I purchased a dedicated medium pressure gauge which I can click onto the inflator hose and which I can use to regularly (2-3 times a year) monitor the "healthy state" of my regs, and the regs of my son and daughter, (check if the medium pressure is still OK, if it is stable, if it quickly returns to its value after getting some air from the reg, etc.) and if everything is OK there is no need whatsoever to bring the reg to the dive shop... So in practice I only bring my reg, or part of it (e.g. only 1st stage or only 2nd stage), to the dive shop for repair/maintenance when it's needed (about every 300 dives or so) and stay next to the technician while he's working on the reg and 20mins later I'm back on the street with my reg... it saves time, it saves money, it avoids unnecessary problems with the regs...
The third time was a "planned" OOA... april 2004... also in a quarry... I dove with 2 buddies and after 40mins one of them got cold (water temperature was 6C) and we took him to the entrance of the quarry to get out of the water and the other buddy and me continued our dive, playing around with our reels on/in an underwater concrete building which is sitting in that quarry at 20m depth... and we kept playing/exercising till I only had a few tens bar air left in my tank (I had a 15liters mono, my buddy a double 12liters) and started rewinding our reels. At that moment my Aladin Air (air integrated) dive computer went completely dead (the LCD display already got dim on previous dives, so I knew the battery was almost flat) and of course I also didn't have any reading anymore of the air pressure in my tank... So I decided to turn this into another "exercise" underwater and I signaled my buddy to simply keep on diving at depth and I wanted to experience how it felt to run out of air... so after a while I had the impression that getting air from my reg was getting somewhat harder and indeed, a few breaths later there was no air coming out anymore. So I signaled an OOA to my buddy and took his backup reg to breathe and we started to ascent... halfway, at 10m depth, we stopped and I took again my reg to see if I could breathe again, and indeed, as expected (because of the reduced water pressure), I could breathe two times... so we continued to ascent till the surface and there I could fully inflate my BCD with the air left over in my tank. So it was a "planned", or at least "expected" OOA, which was quite an interesting and instructive experience since I could clearly "feel" that an OOA was coming along, and while ascending there was still enough air in my tank to have a few breaths and at the surface there was still enough air left to inflate my BCD. So it was a very reassuring experience!
The fourth time... more recently... another dive with 2 buddies... winter time, freezing cold, and it was the 3rd dive of that day, we did prepare our setup and it turned out that there was a problem with the tank of one of my buddies but I have 4 tanks with me in my car so I took a full tank out he could use for the dive and helped him with mountain his reg (I'm using DIN 1ste stages and he's using Yokes, so I have to put DIN inserts back in the valves, etc.) and "lost" some time with that and because the 3rd buddy in the meantime was already fully equipped and waiting for us I had to hurry to get my setup ready... Because of the freezing cold water and the risk at freezing and free flow of the regulators in winter time we don't open the valves and check the regs at the car but only open the valves at the time of entering the water and we only start breathing once we're submerged. So, we jumped into the water... OK... OK... let's get down... I was leading the dive, the viz was not that good, and after 10mins or so while we were down at about 12m I wanted to put some extra air in my dry suit and in my BCD but this did not go well, and I also started having problems with breathing... oops... looking at my manometer it told me that I ran out of air after only 10mins or so, so I could not really believe that this was true and assumed something was wrong with the electronic manometer of my Aladin Air... so I tried to get air from my reg, at no avail, I took my redundant air but couldn't breathe from it either, inflating my BCD nor dry suit did succeed... and I have totally no air left in my lungs... so I had to fin to the surface, which luckily was only 12m away... my buddies because of the low viz did not really notice what had happened, they also surfaced shortly after me and we went out of the water... What had happened? After taking the full tank (which was meant for me for this 3rd dive) out of my car to give it to my buddy, most probably because I was trying to hurry because the 3rd buddy was almost ready, I accidently took a tank for myself which I had used for one of the previous dives and which was almost empty and because of the freezing temperatures I didn't check the manometer while building up the rig and because of the low viz underwater at the start of the dive and have to keep an eye on my buddies I also neglected to verify my air supply at the beginning of the dive since it takes a bit of time after opening the tank valve for my Aladin Air to get activated and get a proper readout of the tank pressure... Lessons learned? When preparing for a dive there is no time to hurry!!! Make sure to check everything, and also check everything once more right at the beginning the dive...
