Fiona Sharp death in Bonaire
- Thread starter JohnnyC
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
I cannot imagine planning an 90m dive on air or 20/20.
First, if you go down fast and not breathe the oxygen away, then the PO2 will way too high. The inspiration has a hud that will be blinking RED, AND an extremely annoying buzzer that will make you crazy on problems. So I cannot imagine you plan a dive this way.
If you want to breathe away the oxygen, it takes a lot of time to reach 90m. I have tried it once with an 18/45 in the loop, and off board normal trimix (6/72) to try how long it will take. (and also had 4 bailouts with me, and it was a team dive) It took 22 minutes to reach 92m and then I closed the adv, flushed over the mav with the better mix. It was a completely controlled and planned situation. It is not only breathing away the oxygen, it is also that the volume in your cl's goes down if you go deeper and with the diluent you only can add very slowly. So you will not plan to do it this way.
Another thing is then: if it is air: at 90m, the END will be 100m with a PO2 of 1.3, so more narcotic (in case O2 not narcotic).
I also know that you are not coming deep without gas in the lungs if you don't add enough breathable volume. Had a not functioning mav/adv 1 time on the Sidekick and had to fill/flush from the offboard diluent.
Only 2 bailouts and extremely small cylinders: No trimix diver will plan a dive to 90m this way. You need at least 3 ali80's if you want to do it.
So we don't know what happened. We have some facts: 2 small bailouts, air or 20/20 diluent, a depth of 90m, solo. But we don't know if the dive was planned to 90m.
And with an inspiration that is working, the buzzer will for sure make you awake that something is wrong if the hud does not do.
This all makes that it doesn't like a planned dive.
A sad loss.
First, if you go down fast and not breathe the oxygen away, then the PO2 will way too high. The inspiration has a hud that will be blinking RED, AND an extremely annoying buzzer that will make you crazy on problems. So I cannot imagine you plan a dive this way.
If you want to breathe away the oxygen, it takes a lot of time to reach 90m. I have tried it once with an 18/45 in the loop, and off board normal trimix (6/72) to try how long it will take. (and also had 4 bailouts with me, and it was a team dive) It took 22 minutes to reach 92m and then I closed the adv, flushed over the mav with the better mix. It was a completely controlled and planned situation. It is not only breathing away the oxygen, it is also that the volume in your cl's goes down if you go deeper and with the diluent you only can add very slowly. So you will not plan to do it this way.
Another thing is then: if it is air: at 90m, the END will be 100m with a PO2 of 1.3, so more narcotic (in case O2 not narcotic).
I also know that you are not coming deep without gas in the lungs if you don't add enough breathable volume. Had a not functioning mav/adv 1 time on the Sidekick and had to fill/flush from the offboard diluent.
Only 2 bailouts and extremely small cylinders: No trimix diver will plan a dive to 90m this way. You need at least 3 ali80's if you want to do it.
So we don't know what happened. We have some facts: 2 small bailouts, air or 20/20 diluent, a depth of 90m, solo. But we don't know if the dive was planned to 90m.
And with an inspiration that is working, the buzzer will for sure make you awake that something is wrong if the hud does not do.
This all makes that it doesn't like a planned dive.
A sad loss.
CuzzA
Wetwork for Hire
Everything about the equipment screams a planned a dive to 100-150, which it sounds like the site would have accommodated (i.e. stuff to see). Obviously, the exact profile from the computer, not just max depth, would give greater insight.
But, let's assume it was a planned 300' dive, for which the setup would grossly inappropriate. Surely previous dive buddies would have some insight into that and someone would be in a position to say "she believed in deep air" or being a semi-alpinist when it comes to bailout or whatever. The point is that if this was indeed a planned 300' dive on air DIL, it's hard to believe it was the first time for something like that, solo no less. Even understanding that folks might be reluctant to post it, she was well known and respected and if she was that aggressive in her dive planning, I would expect someone would have said, "yeah, I saw her do something like that once."
But, let's assume it was a planned 300' dive, for which the setup would grossly inappropriate. Surely previous dive buddies would have some insight into that and someone would be in a position to say "she believed in deep air" or being a semi-alpinist when it comes to bailout or whatever. The point is that if this was indeed a planned 300' dive on air DIL, it's hard to believe it was the first time for something like that, solo no less. Even understanding that folks might be reluctant to post it, she was well known and respected and if she was that aggressive in her dive planning, I would expect someone would have said, "yeah, I saw her do something like that once."
Yes, something doesn’t add up for me about the reported depth and the underwater topography.
silent running
Contributor
A ScubaBoard Staff Message...
Rebreathers are not for everyone. But they are varying levels of complexity, ranging from not complex at all and having no electronics (the earliest versions predate scuba by almost a hundred years) to ones with multiple digital sensors and computers. Lots of things we use everyday are more complex than a rebreather, like cars.
(Mod edit)
As I said above, not all rebreathers are complex and the “technology” of them, meaning the basic operating principles and hardware are very simple. (Mod edit)The risks of rebreather diving are real but have very little to do with their complexity. Rather, the risk is the inherently unnatural proposition of breathing, or rebreathing, compressed mixed gas underwater. I have been diving rebreathers since 1998 and had less than 100 open circuit dives before I switched to a rebreather for better wildlife interactions, increased dive time and...increased safety. I won’t go into all the details, but my CCR saved my life at least once and probably a second time as well. How? I was caught in a very extreme tidal down current which sent me to 200’ in less than 5 minutes and from which I had to work at maximum exertion for 30+ minutes to extricate myself. I would’ve used up all my gas and drowned were I diving OC with an Al 80. But I knew I had 10+ hours of gas on my back and set about pulling and kicking myself back up to the surface.
Experienced CCR divers of the previous generation often gained their experience in OC tech diving, which is different enough to require different habits. Both OC tech and rebreather diving require a regimented approach, and as such some habits may have been hard to break and relearn for those older OC tech divers. Sadly, I have heard of newly trained CCR divers who were experienced OC tech divers, making very fundamental mistakes right after training which proved fatal. This is perhaps proof of those hard to break habits, and the difficultly of creating new habits on top of the old. I brought up my example above as someone who went almost straight to rebreathers, as an alternative to this idea of extensive OC tech experience being a benefit. Meaning that I had none of the OC tech habits and have spent over 1000 hours on CCR with no significantly dangerous user errors.
Further on the subject of experienced diver fatalities on CCR, many of those divers were doing dives which were well beyond the range of recreational scuba and carried significant risk to begin with. When people realize they have 10+ hours of gas whose consumption does not vary with depth, they may become very ambitious, enough to push various boundaries, dive planning and physiology wise. This must also be considered when looking at any statistics about CCR fatalities.
(Mod edit)
As someone who has had some very bad motorcycle accidents, all while sober and in dry weather, none of which any fault was assigned to me, I find CCR diving vastly safer and more rewarding.
IMHO, the actual risks of CCR diving are themselves difficult to fully assess and involve equipment design and the mindset necessary to facilitate awareness of the known risks and their mitigation. The good news is if you do most things right, you will have lots of time to solve a problem and there will be no sweat. The bad news is, some designs are more mistake tolerant than others, and some people have mindsets which are not conducive to breathing compressed mixed gas underwater, IMHO...
Dan
Contributor
Which CCR brand do you use and how deep have you gone? You mentioned 200' depth by accident, I assume you just use air during that time and you didn't get into nitrogen narcosis?
Great summary, thanks.
Similar threads
