fsardone
Solo Diver
Hello everybody,
A little near miss (or two) which ended up with an aborted dive no consequences, but the thought process might provide points to ponder.
Me and a frequent buddy meet at a lake location for a fairly deep dive. Plan is to follow a guideline starting at shore, follow it to a junction at 40+ meters, follow a right fork to a landmark at 60 meters, assess situation there and then:
- either keep following it to 74 meters to another landmark, keep going at 74 meters until another fork and then take the guideline that bring us back to the surface;
- or come back on the original guideline up to 45 meters and cross maintaining the 47mt bathymetric until intercepting the resurfacing guideline of the previous point.
Navigation is a circuit, quite easy not an issue (mentioned here to give you a sense of what laid ahead), visibility is very bad all the way up to 30-35 meters then (usually) it becomes very good.
Configuration is CCR (me on APD Inspo friend on JJ - dil me 12/50 friend 16/50) bailout three stages each (self sufficient with deep, 50/20 and oxy) bottom time not exceeding 30’ average depth about 45-50 (slow descent following the slope and about 15 minutes below 50).
Strike 1
Assembling my kit the night before I was unhappy of negative test. Counter-lungs where checking all right (you can connect the two counter-lungs with one of the hoses going to the scrubber and with the OCB/DSV in place check the loop without the scrubber). I had to disassemble the head check the o’rings reassembly everything. Now I was satisfied with the neg check (and again for the positive).
Strike 2
Buddy has bought a used JJ completed the crossover and building hours on the machine. We meet at lakeside and after bringing the kit to the entry point and completed calibration and pre-breathe we don the kit. At this point he calls me over because the rebreather did no feel right and he could not stand up. To make a long story short the JJ came with non self locking nuts that came undone between the backplate and the frame. He had his toolbag and decided to put self locking nuts. I did not want to de-kit and the reb being heavy on my back told him I was going in the water (also it was a good time to check if my heated undergarment and battery pack were fit for purpose). So I waited in the water for over 40 minutes and not breathing from the reb.
Strike 3
A bit concerned by the chain of events, we make a good surface brief and we agree to meet at 6 mt at the start of the guidelines to make a very good bubble check and then push forward. At this point I get a CO2 High - ascend first warning by my CCR (this is if ppCO2 is above 5 mbar). I was a bit puzzled because during pre-breath (which won’t tell you if you have CO2 issues by feelings but only if the reb works) the temp stick came on (meaning the scrubber was heating up as expected and no CO2 worning came on). So, I think maybe is the cold scrubber being in the water for so much time not breathing it. I had experienced this after a deep dive to 80 meters and after bailing out, the scrubber went cold and alarmed the reb but it was not a CO2 warning it was a scrubber warning. So, I stayed at 6 meters dil flushed and apparently the warning went away. In the back of my mind was also a couple of preceding warning which were unsubstantiated. I waited a bit and, after communicating with buddy (he was aware of issue since the beginning), we decided to push forward. So, we start along the guideline, descend down to about 36 meters and now I get a first warning CO2 High Ascend and again a CO2 High second warning bailout. This happens at 10 mbar ppCO2 and it is quite serious. No symptoms yet. But I was not going to push forward, also CO2 hit is nothing to have fun about. We turn around along the guideline, my deep bailout was 12/60 and my next gas was 50/20, so I switch OC for a couple of sanity breaths, reduce depth and immediately all CO2 warning go out, I go back on the loop and continue ascending. At about 12 meters the CO2 first warning comes on again. I stay on the loop, no symptoms, no deco obligation and within reach of surface, at 6 meters I get again a CO2 second warning – Bailout. We were almost out, and I stayed on the loop for a couple of more minutes.
Analysis.
About Strike 2 - It might have been the most serious issue. If the reb come undone while underwater and it is positively buoyant , it might create couple of issues: diver becomes negative and loop is pulled out of mouth. Also if relying on OCB you just lost it. The whip connecting the bailout bottle is also pulling up with the reb and will make it difficult to pull the reg out and breathe from it.
About Strike 3 - Upon disassembly of the reb I found out that about 1 cm (less than half inch) of the o’ring sealing the scrubber (out of a circumference of 48 cm about 20 inches) was mis-seated allowing a partial scrubber bypass. Following strike 1 - I did not disassemble that o’ring during my partial rebuild and consequently I ignored it on reassembly. Bad choice.
Lesson identified
1. Mechanical integrity: do not ignore the bolt and nuts: shake the thing!
2. Be extra careful when deviating from usual patterns and restart from the beginning of the checklist
3. Do not ignore warnings. It is better to honor a false warning and be there to dive another day than ignore a real one and pay the price. We are not on a mission, we are there to have fun.
Also in my thought process there is the fact I have a medical condition which is believed to possibly increase CO2 tolerance, I have discussed this in person with one of the medical moderators of this board (before this happening) and my particular situation might not lead to this but still it is a concern.
Always:
1. Keep breathing
2. Analyze the situation
3. Take proper action
Most of the time (almost always) it is not what happens that kills you but how you react to it. When you have a choice, always follow the safest course of action. Live to dive again.
Thanks for reading all of this I hope it might be of help in order to learn from my experience
A little near miss (or two) which ended up with an aborted dive no consequences, but the thought process might provide points to ponder.
Me and a frequent buddy meet at a lake location for a fairly deep dive. Plan is to follow a guideline starting at shore, follow it to a junction at 40+ meters, follow a right fork to a landmark at 60 meters, assess situation there and then:
- either keep following it to 74 meters to another landmark, keep going at 74 meters until another fork and then take the guideline that bring us back to the surface;
- or come back on the original guideline up to 45 meters and cross maintaining the 47mt bathymetric until intercepting the resurfacing guideline of the previous point.
Navigation is a circuit, quite easy not an issue (mentioned here to give you a sense of what laid ahead), visibility is very bad all the way up to 30-35 meters then (usually) it becomes very good.
Configuration is CCR (me on APD Inspo friend on JJ - dil me 12/50 friend 16/50) bailout three stages each (self sufficient with deep, 50/20 and oxy) bottom time not exceeding 30’ average depth about 45-50 (slow descent following the slope and about 15 minutes below 50).
Strike 1
Assembling my kit the night before I was unhappy of negative test. Counter-lungs where checking all right (you can connect the two counter-lungs with one of the hoses going to the scrubber and with the OCB/DSV in place check the loop without the scrubber). I had to disassemble the head check the o’rings reassembly everything. Now I was satisfied with the neg check (and again for the positive).
Strike 2
Buddy has bought a used JJ completed the crossover and building hours on the machine. We meet at lakeside and after bringing the kit to the entry point and completed calibration and pre-breathe we don the kit. At this point he calls me over because the rebreather did no feel right and he could not stand up. To make a long story short the JJ came with non self locking nuts that came undone between the backplate and the frame. He had his toolbag and decided to put self locking nuts. I did not want to de-kit and the reb being heavy on my back told him I was going in the water (also it was a good time to check if my heated undergarment and battery pack were fit for purpose). So I waited in the water for over 40 minutes and not breathing from the reb.
Strike 3
A bit concerned by the chain of events, we make a good surface brief and we agree to meet at 6 mt at the start of the guidelines to make a very good bubble check and then push forward. At this point I get a CO2 High - ascend first warning by my CCR (this is if ppCO2 is above 5 mbar). I was a bit puzzled because during pre-breath (which won’t tell you if you have CO2 issues by feelings but only if the reb works) the temp stick came on (meaning the scrubber was heating up as expected and no CO2 worning came on). So, I think maybe is the cold scrubber being in the water for so much time not breathing it. I had experienced this after a deep dive to 80 meters and after bailing out, the scrubber went cold and alarmed the reb but it was not a CO2 warning it was a scrubber warning. So, I stayed at 6 meters dil flushed and apparently the warning went away. In the back of my mind was also a couple of preceding warning which were unsubstantiated. I waited a bit and, after communicating with buddy (he was aware of issue since the beginning), we decided to push forward. So, we start along the guideline, descend down to about 36 meters and now I get a first warning CO2 High Ascend and again a CO2 High second warning bailout. This happens at 10 mbar ppCO2 and it is quite serious. No symptoms yet. But I was not going to push forward, also CO2 hit is nothing to have fun about. We turn around along the guideline, my deep bailout was 12/60 and my next gas was 50/20, so I switch OC for a couple of sanity breaths, reduce depth and immediately all CO2 warning go out, I go back on the loop and continue ascending. At about 12 meters the CO2 first warning comes on again. I stay on the loop, no symptoms, no deco obligation and within reach of surface, at 6 meters I get again a CO2 second warning – Bailout. We were almost out, and I stayed on the loop for a couple of more minutes.
Analysis.
About Strike 2 - It might have been the most serious issue. If the reb come undone while underwater and it is positively buoyant , it might create couple of issues: diver becomes negative and loop is pulled out of mouth. Also if relying on OCB you just lost it. The whip connecting the bailout bottle is also pulling up with the reb and will make it difficult to pull the reg out and breathe from it.
About Strike 3 - Upon disassembly of the reb I found out that about 1 cm (less than half inch) of the o’ring sealing the scrubber (out of a circumference of 48 cm about 20 inches) was mis-seated allowing a partial scrubber bypass. Following strike 1 - I did not disassemble that o’ring during my partial rebuild and consequently I ignored it on reassembly. Bad choice.
Lesson identified
1. Mechanical integrity: do not ignore the bolt and nuts: shake the thing!
2. Be extra careful when deviating from usual patterns and restart from the beginning of the checklist
3. Do not ignore warnings. It is better to honor a false warning and be there to dive another day than ignore a real one and pay the price. We are not on a mission, we are there to have fun.
Also in my thought process there is the fact I have a medical condition which is believed to possibly increase CO2 tolerance, I have discussed this in person with one of the medical moderators of this board (before this happening) and my particular situation might not lead to this but still it is a concern.
Always:
1. Keep breathing
2. Analyze the situation
3. Take proper action
Most of the time (almost always) it is not what happens that kills you but how you react to it. When you have a choice, always follow the safest course of action. Live to dive again.
Thanks for reading all of this I hope it might be of help in order to learn from my experience
