Filmmaker Rob Stewart dies off Alligator Reef

[Cowfish Aesthetic]

Assume two things that seem relatively certain:

1. Stewart had been diving rebreathers since at least 2006, and
2. Stewart was either completing or had just completed hypoxic trimix training when he died.

Even if Sotis was hypercapnic, doesn't hypoxia still make more sense than Stewart accidentally flooding his loop?

 

[cerich]

doesn't hypoxia still make more sense than Stewart accidentally flooding his loop?

those two are not in fact exclusive, both could and IMHO likely did occur, pass out on surface, loop falls out and floods

 

[oldschoolto]

Me,Sitting on the couch in northern Maine.... And Netdoc being down the street from the accident .. I think he may have a better grip on what happened... He can hear the little birds chirping....

Jim...

 

[Wookie]

let me break it down for you..It's a very, very poor baseline to work from because in real life even thinking that is a baseline is flawed. Very flawed.

An absolute baseline for min BO gas planing starts with a real; understanding of the likely REAL world BO gas needed in an emergency, which is what BO gas is all about.

In flying terms, what you are saying a baseline would be ,like planing a flight with just enough gas to maybe possibly being able to glide in to a landing from your cruise altitude, without factoring in things like wind, altitude density etc.

it's grossly poor.

Educate me.

I know that a trip to the Dry Tortugas on the Spree burns a thousand gallons of diesel fuel. I know this because I've made no fewer than 200 trips out there. I would never run the Spree tanks lower than 1000 gallons. Just because I just don't. So, I would never leave the dock with less than 2,000 gallons, but more likely 2,500.

But I know that the trip will take 1,000. That's my baseline. Would I go with 1,000? No, but my baseline is 1,000. How is what min rmv does any different?

 

[Wookie]

Assume two things that seem relatively certain:

1. Stewart had been diving rebreathers since at least 2006, and
2. Stewart was either completing or had just completed hypoxic trimix training when he died.

Even if Sotis was hypercapnic, doesn't hypoxia still make more sense than Stewart accidentally flooding his loop?

I would not consider a Draeger Dolphin (the rebreather he was diving in 2006) to be a rebreather in the context of this discussion any more than I would consider a Prius a car if we were discussing LeMans cars. Yes, the Dolphin shares some characteristics with a rEvo. Like a Prius has 4 tires.

 

[packrat12]

The 2 computers will hold much of that information on them. Peter S. probably already knows his trace on it and I would hope he had turned it over to the investigative team. The recovered computer from Rob probably is already understood also. It should be easy to see the PPO2 levels prior to and after surfacing for both Peter and Rob. These traces will answer fairly definitively the PPO2 Hypoxia question. The Hypercapnia question can be derived from this data also as the 'one of the other alternatives' if PPO2 looks good. Gas testing should also be available on the recovered CCR assuming there is enough left.

I will almost guarantee that Rob's DSV was found open. This does not necessarily have anything to do with him positioning it. If he passed out on the surface or had a debilitating issue, he would not necessarily have been able to close it. It very well may be found open. I do see NetDoc's opinion but in a different light, it is possible that the deck commotion distracted him from closing it. My CCR (Prism 2) gains about 17 lbs when fully flooded, which is unlikely with simply leaving the DSV open. I have seen very experienced instructors fail to close theirs because they were chatting so this is not necessarily inexperience if it did happened. Even airlines have crashed with very experienced pilots due to distraction. The PPO2 trace should help here but not being hypoxia would leave 2 arm chair QB possibilities, hypercapnia or distraction/inaction.

 

[packrat12]

I would not consider a Draeger Dolphin (the rebreather he was diving in 2006) to be a rebreather in the context of this discussion any more than I would consider a Prius a car if we were discussing LeMans cars. Yes, the Dolphin shares some characteristics with a rEvo. Like a Prius has 4 tires.

You forgot Steering wheel, gas, brakes, gears, etc. Performance needs experience but fundamentally they are the same. I would not consider my 300ZX experience (Nissan Turbo Sports car) equivilent LeMans either but then the Queen of Nassau is not the 'Andrea Doria' or better the 'Empress of Ireland'.

 

[MarkFlory]

let me break it down for you..It's a very, very poor baseline to work from because in real life even thinking that is a baseline is flawed. Very flawed.

An absolute baseline for min BO gas planing starts with a real; understanding of the likely REAL world BO gas needed in an emergency, which is what BO gas is all about.

In flying terms, what you are saying a baseline would be ,like planing a flight with just enough gas to maybe possibly being able to glide in to a landing from your cruise altitude, without factoring in things like wind, altitude density etc.

it's grossly poor.

Look you have to have a baseline in anything in order to plan real conservatism , if you don't you are just guessing.
Using your Aviation example, first you must know your baseline like a small plane burning 9 gallons per hour, now you can add a half hour of fuel if you are flying VFR and if you're flying IFR you add an extra hour worth of fuel. But you must know that a your plane ( on a normal/good day ) burns 9 gallons per hour.
We do the same thing with our bail out gas, we must test ourselves and figure out what our RMV is on a normal/good day , then we can figure out a baseline of how much gas we need to bailout and complete deco on a normal/good day. Once we have those figures we then can either carry more BO gas or subtract dive time to add a real conservatism for a bad day that we feel safe with.
IMO you can't carry enough gas if you take a C02 hit with a big deco obligation so we shouldn't kid ourselves, if that happens you probably are smoked.

 

[Wookie]

If IANTD doesn't toss him out an an instructor now, I'll be even more ashamed on the training industry than I am now. Some people simply don't belong in this business.

I'm going to play devils advocate here, regardless of my personal feelings. I'm dead inside anyway.

I think it's a reasonable assumption that Stewart was a certified diver. Certified (and maybe qualified) to make the dive he did. He had 4 days to complete his training dives, which is not a stretch by any means. The South Florida mill is designed to make heroes from zeros, like the Pattaya Beach/Kao Tao mill is designed to do with OWSIs.

Most people on this board will shout that they are "certified divers, they don't need to follow industry rules". It was my biggest contest when running the Spree. Our rules followed industry standards to the letter. Yes, the rules were bent for certain individuals who I felt understood the risks and whose heirs were willing to accept them. That philosophy served me well. Someone like you or another diver with more trimix dives than I have open water dives would be given a pass if they asked. Peter Sotis was one of those people. Although he never dove with us, had he asked to dive outside of industry standards, as a diver who understood the risks I would have allowed him to do so. Other operators have a free for all. I have no issue with what other operators do, I don't have to defend them in court.

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.

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?

I guess my point is, we don't know what the status of Stewart was when he went in the water, although I guarantee that by now his certification was properly issued the day before. That makes Stewart a big boy and responsible for his own safety. And 100% of experienced rebreather divers I personally know would fight tooth and nail to proclaim that they are certified and therefore responsible for themselves in the water. Without getting all emotional about Sotis personally, tell me where my reasoning is flawed.

 

[St John the Diver]

The 2 computers will hold much of that information on them. Peter S. probably already knows his trace on it and I would hope he had turned it over to the investigative team. The recovered computer from Rob probably is already understood also. It should be easy to see the PPO2 levels prior to and after surfacing for both Peter and Rob. These traces will answer fairly definitively the PPO2 Hypoxia question. The Hypercapnia question can be derived from this data also as the 'one of the other alternatives' if PPO2 looks good. Gas testing should also be available on the recovered CCR assuming there is enough left.

I will almost guarantee that Rob's DSV was found open. This does not necessarily have anything to do with him positioning it. If he passed out on the surface or had a debilitating issue, he would not necessarily have been able to close it. It very well may be found open. I do see NetDoc's opinion but in a different light, it is possible that the deck commotion distracted him from closing it. My CCR (Prism 2) gains about 17 lbs when fully flooded, which is unlikely with simply leaving the DSV open. I have seen very experienced instructors fail to close theirs because they were chatting so this is not necessarily inexperience if it did happened. Even airlines have crashed with very experienced pilots due to distraction. The PPO2 trace should help here but not being hypoxia would leave 2 arm chair QB possibilities, hypercapnia or distraction/inaction.

Due to the counterlung design of the rEvo as compared to OTS counterlungs, it will fully flood in about fifteen seconds with an open DSV above the counterlung level.