Filmmaker Rob Stewart dies off Alligator Reef

[Effervescent]

Possible silly question from a non-CCR diver:
Is there any aspect of CCR training which would allow a student to (safely) experience mild hypoxia or hypercarbia?
[like for example, experiencing being narc'd on deep dive training in AOW?]

Sorry if this is a repost but here is a really interesting video posted by Smarter Every Day about how hypoxia can affect your brain. It's really shocking to see Destin just sit there giggling while the operator is telling him that he's going to die if he doesn't put his mask on.

 

[cephalopod2]

This thread is pushing forward on multiple paths simultaneously but it seem there are at least 5 stages identified where serious injury might have been able to be lessened/avoided

1. Decision to do 2 -- or 3 -- planned 220 ft dives X days/weeks after trimix class, with X CCR/trimix experience, X equipment and gases, X team members, X goals, etc.

2. Decision to do the third 220 ft dive - reportedly a bounce dive to free an anchor (per Brian Stewart interview) - potentially an extemporized dive (reported but unconfirmed)

3. Decisions of what equipment, gas and team members to take/send on that third dive

4. Actions taken/not taken by the 2 divers on the ascent from the 3rd dive and at the surface

5. Actions taken/not taken by those who were not on the dive (divers or passengers not involved in the third dive, any crew) once both divers had surfaced

There's been a lot of attention to #3-4 in the last 24 hours, understandably, but what about #2 - before the dive even occurred?

Suppose it was an extemporized dive to free the anchor. Even if the most experience CCR diver proposed a high risk dive plan, and if Mr. Stewart agreed to join to that dive for whatever reason, could there have been an opportunity not only for Sotis or Stewart (who may have been the only ones reading their gauges, computers, etc or with full knowledge of their profiles on dives 1 and 2, and who of course remain responsible for their own safety) but for anyone else on the boat whether diving or not to help achieve a safer resolution than a bounce dive to retrieve the anchor?

Could those on the boat have decided to leave the anchor on the bottom for that afternoon if the risk of retrieving it (or of making a serious error in the process of receiving it) were too high?

 

[wedivebc]

Experiencing hypercarbia was a part of my rebreather class.

That explains a lot...

 

[uwxplorer]

Not tying a buoy to the line and coming the next day (or week) to retrieve it was a missed opportunity, to say things nicely.

 

[RichardC]

I've been reading this thread with much sadness because I have great respect for the conservation efforts of Rob Stewart and because I'm a rEvo diver myself so it cuts close to home both ways.

This is my first post on this forum and that is itself weird as my first post on RBW was when I lost a friend diving an AP unit ten years ago almost to the day. I'm from the other side of the pond and I don't know the people or dive operations concerned with this incident.

I regularly dive hypoxic mixes in cold (40F) and warm water and do not agree that the rEvo ADV is a problem. It is easy to adjust such that it is tight and you can feel the bottom of the lungs even with high He mixes. I never have an issue with accidental triggering on the surface or otherwise and I know when I am pulling on the ADV.

I think the RMS is a useful tool. I have found it to be very reliable for the cycling of the scrubbers, the changes in predicted time remaining and my actual dive durations match, but again it has to be calibrated for the user as we all have different metabolisms. I have found it to be correct for the first scrubber over hundreds of dives and I know if second scrubber has become active. However I never dive on the prediction of the second scrubber because then there is no backup.

I have seen enough of these kind of discussions to realise that some people will jump in to trash one unit, usually to promote one they use, sell or teach, and also I realise that there is no such thing as a perfect rebreather. They all need adjustment to suit the user and they all have weaknesses, which is why good training, practise, slow advancement and an abundance of caution are essential.

 

[Q1988]

I didn't make my point clear. Our friend said:

For whatever reason, Sotis is not giving us his side of the story. If you're going to dis people for not using their name, then why not dis Sotis for not posting at all? There are certain times when you should either shut up or remain anonymous. I would suggest that both are born out of fear.

NetDoc et al: just to interject; but all dive accidents have opinions about every element of the incident. Shoulda done this, shoulda done that, is it irresponsible, is it reckless, is it because the pay out is more, who knows. Can we learn from this event? It it turns out to be like other unfortuneate events that COD was drowning it is not likely. IMO we are all solo divers.

 

[St John the Diver]

I regularly dive hypoxic mixes in cold (40F) and warm water and do not agree that the rEvo ADV is a problem. It is easy to adjust such that it is tight and you can feel the bottom of the lungs even with high He mixes. I never have an issue with accidental triggering on the surface or otherwise and I know when I am pulling on the ADV.
.

This is in conflict with my experience (I dove one for many years, only retiring it this summer). The "fix" suggested by the factory for the too-easy cracking pressure was to use cable ties to add a piece of springy plastic to the lever arm to reduce sensitivity. Many rEvo instructors here quietly suggested to remove the lever completely and I know several who have done exactly that. Perhaps there's been a change since then.

I think you mentioned that you could add a slider to isolate the ADV? I can't see how or where, and as you know a modification like that voids CE.

Welcome in any event.

 

[Dsix36]

I switched from a rEvo to a Defender. Disclaimer done.

From day one on the rEvo until the end of time, I will say the ADV is a POS and It needs a redesign. With that said it is still extremely easy to get it adjusted in a manner that will not be conducive to the possible issues of going hypoxic on the surface with 10/50. I dive 10/50 almost exclusively (even on 10' Blue Heron Bridge dives) and have never even came close to low PO2 from the ADV. The ADV will not trigger accidentally or without me working hard to make it fire.

I have no idea about the adjustment of the ADV on Rob's unit. It could very well have been at fault, but there is no reason to bash the unit over a simple adjustment issue. Bottom line in regards to surface PO2 is the first rule in rebreather training and diving - ALWAYS KNOW YOUR PO2.

 

[The Chairman]

Many rEvo instructors here quietly suggested to remove the lever completely

No need to remove it. It flips easily out of the way. My unit during training was quite problematic, so I defeated it.

 

[Christopher_B]

So the posts clearly show us the training progression... CCR Air to CCR Hypoxic Trimix in <6mo

Is that a reasonable rate of progression or advanced but feasible? Or dangerously quick?