Filmmaker Rob Stewart dies off Alligator Reef

[Dsix36]

Was he in a drysuit?

I have no idea. the drysuit was in regards to another buoyancy factor possibility.

 

[RichardC]

Either way, I'm not losing sleep over the lack of a gag strap.
- I know a lot of people don't use them IRL
- plenty of other things that occurred would be far more likely to disrupt my slumber patterns

I'm not going to war with anyone over gag straps, but I think they are a good idea. It takes the weight off my jaw during the dive, I don't have to grip the mouthpiece and hopefully it would keep the loop in if I have a tox or similar, so I use one. It might have made a difference in this incident (or not).

On the other hand, everyone is free to dive as they see fit, but if they choose not to use one then it is just that, a personal choice. I think it should at least be an option that is presented during training and I got the impression that the straps were not even there. Maybe I'm wrong about that.

 

[lamont]

Anyway, whether Sotis is responsible or not depends a lot on whether you believe a buddy has an obligation to his buddy, or if a team has an obligation to the team. I don't know the circumstances of this particular dive, but I've watched a lot of planning for very similar dives. 2 or 3 folks enter the water and all are carrying 40s. They are practicing what might be called team bailout. One has a bottom mix and a 40 of 50%. The other has a normoxic mix and a 40 of 80%. The third has a 40 of 20/20 and a 40 of O2. Or whatever the breakdown is, they have the gas so that if one rebreather fails, between the three of them they can get back to the surface.

This is taking the wrong lesson from team diving. If you have team separation now compiled with a rebreather problem, then you have insufficient bailout and you're dead.

Reminds me of Program Managers who learn about Agile methodology and what they start doing is hour long morning standup meetings to go over the Gantt chart. This is missing the point.

Assume Stewart was carrying a camera. He doesn't want bailout bottles in his way. You and I both know a certain well known Northeast wreck captain who dives without bailout at all. He is also an accomplished videographer. With thousands of dives. Would you tell him on your boat that he wasn't welcome?

Yes, diving like that he's a liability and nobody should let him on their boat.

I know of a dead CCR videographer who dove like that. He probably shouldn't have. He might still be around.

 

[RichardC]

Except that..... He sank and died.

So I'm pretty sure he wasn't positive..

;-)

Yes that much is evident, but, as my post just above your last one said, a drysuit can inadvertently dump in the case of a loss of control. For example if you have not closed off the dump properly, or you are relying on position in the water to keep it inflated or it's a cuff dump system and your arm floats to the surface or the neck seal vents or......

So he certainly ended up negative, but we don't know the chain of events that got him there. If he did loose the loop and was initially sufficiently buoyant, he would not have stayed that way if the suit dumped.

 

[lamont]

And is there any actual evidence in this thread (sorry there's 30 pages of it now that I haven't read and I think I ox-toxed trying to read half of it) that points to hypoxic bailout or the DSV/counterlungs killing him due to flooding?

It still sounds like this was a third dive to retrieve the hook, and it was likely a bounce dive, and bubble shunting and cerebral arterial gas embolism still explains everything?

I've been involved in one incident involving lung barotrauma and CAGE and the diver in that case made it to the surface conscious and responsive and it took a few minutes for her to go unconscious and die. The fact that he could signal "OK" and then die and not be found on the surface is still consistent with DCS/CAGE.

 

[RichardC]

The answer to this is straightforward but not black and white - in a good technical diving class one will learn how to plan decompression dives appropriately. Period.

The dives in this example are pretty much outside the line of what at least 90% of tech divers would consider safe.

OTOH, i am not going to say absolutely that I would not do three deco dives in a day. I can think of some profiles that would require deco, for example ten minutes of O2 deco, that I would repeat for a total of three dives in a day.

That is why there are no "rules" - a good tech class should really teach someone decompression theory and enable them to make good decisions. Then, the diver should take that knowledge and build their experience gradually.

Just MHO of course.

I think one possible issue with multiple deco dives in one day is that the slow tissues will not be fully off-gassed between dives. There is some evidence (and I'm thinking of the NEDU deepstops work here) to suggest that the effect of tissue loading in the slow tissues is not fully understood and that what would once have been considered a low saturation may matter more than previously thought.

 

[uwxplorer]

Is anyone able to run these profiles through Add Helium's TruDive Planning software?

This is a bit late of an answer, but my understanding is that TruDive is no different from Multideco (or the Shearwater computer controlling the rEvo) in that it implements a Buhlman ZHL16C algorithm with gradient factors (or VPM B, your choice).
I ran the profile discussed in the video (170 ft, 28 min BT), using all the parameters I could gather from it, and Multideco gave me 70 min RT where TruDive shows 78 min RT. As a comparison, the Shearwater returns the same value as Multideco (a good thing, since you dive with the Shearwater, not Multideco or TruDive, unless you print or write down their plan - which you should, as a backup).
So, if anything, Trudive recommends a more conservative profile.

This being said, if I were a TruDive customer, I would ask about the discrepancy with two of the most used deco software (all supposedly implementing the same algorithm)...

 

[scubadada]

I think one possible issue with multiple deco dives in one day is that the slow tissues will not be fully off-gassed between dives. There is some evidence (and I'm thinking of the NEDU deepstops work here) to suggest that the effect of tissue loading in the slow tissues is not fully understood and that what would once have been considered a low saturation may matter more than once thought.

Sorry, stupid question. Shouldn't the leading tissues be accounted for on the subsequent dive and be taken into account in the dive profile, computer or planning software?

 

[uwxplorer]

Sorry, stupid question. Shouldn't the leading tissues be accounted for on the subsequent dive and be taken into account in the dive profile, computer or planning software?

They are.

 

[scubadada]

This is a bit late of an answer, but my understanding is that TruDive is no different from Multideco (or the Shearwater computer controlling the rEvo) in that it implements a Buhlman ZHL16C algorithm with gradient factors (or VPM B, your choice).
I ran the profile discussed in the video (170 ft, 28 min BT), using all the parameters I could gather from it, and Multideco gave me 70 min RT where TruDive shows 78 min RT. As a comparison, the Shearwater returns the same value than Multideco (a good thing, since you dive with the Shearwater, not Multideco or TruDive, unless you print or write down their plan - which you should, as a backup).
So, if anything, Trudive recommends a more conservative profile.

This being said, if I were a TruDive customer, I would ask about the discrepancy with two of the most used deco software (all supposedly implementing the same algorithm)...

I'm not at all sure that all the computers and planning software give exactly the same results when running the same algorithm. I would be interested in an independent comparison.