Filmmaker Rob Stewart dies off Alligator Reef

[Dan]

I agree; however, I do know commercial guys doing repetitive dives to these depths on Trimix open circuit, but their bottom times are very short. 4-5 minutes. They aren't shooting video though.

I'm not a CC diver, but have dove with a few CC divers, done a fair amount of research, participated in breaking down a unit before and watched a lot of the DAN videos on the subject, mostly Mr. Simon Mitchell's presentations. One of the things that has stuck with me from his presentations is regarding the extraordinarily high number of deaths with rebreather divers compared to OC. At the end of the day, a fallible human really needs to think about what he's doing and why he's doing it. The technology easily allows divers to push limits and put themselves in places and situations they normally wouldn't find themselves in OC. And taking high risks without thinking about self preservation.

Case and point. Too much too fast and relatively inexpensive repetitive deep Trimix dives which would normally be cost prohibitive on OC allowed Rob to probably push the limits.

A good watch for those who haven't seen this one before.

That's a good educational CCR presentation. Thanks for posting.

If a 90m dive takes 3 hours, as shown in the chart in the presentation, below, multiply it by 3 + 2 surface intervals. It'll be a pretty long & physically grueling day.

 

[St John the Diver]

Actually it was the solenoid seat was installed upside down in Richards meg. Also his cells were many months past their due date. His death was deemed drowning as a secondary effect of oxygen toxicity. NEDU did a very thorough examination of the untit.

Encouraging.

In conflict with my own experience, but encouraging.

As Wookie knows, when the skipper of a navy unit changes the entire thing changes. It'll be interesting to see how this one plays.

 

[St John the Diver]

That's a good educational CCR presentation. Thanks for posting.

If a 90m dive takes 3 hours, as shown in the chart in the presentation, below. Multiply it by 3 + 2 surface intervals. It'll be a pretty long & physically grueling day.

View attachment 395479

I bet they wouldn't be using nitrox for deco gas...

But yes it's a long dive. Nobody would do two in the same day. Your example is deeper than the accident dives. Two 220 footers are considered the norm on a day on the Doria, but three? Not ever.

 

[Wookie]

I bet they wouldn't be using nitrox for deco gas...

But yes it's a long dive. Nobody would do two in the same day. Your example is deeper than the accident dives. Two 220 footers are considered the norm on a day on the Doria, but three? Not ever.

Especially if the divers were out of everything except dil. But that's just a rumor.

 

[Christopher_B]

The training agencies aren't interested in looking too closely at the instruction given to the victim

Despite/Given Peter Solis' role as a member of the IANTD board of advisors, you'd think that they would investigate it with full diligence, no? Or do agency board members close ranks when what might appear to be negligence occurs? I presume it is only the training agency itself that can verify the victim's training certification and records and that no-one from the outside can.

 

[St John the Diver]

Despite/Given Peter Solis' role as a member of the IANTD board of advisors, you'd think that they would investigate it with full diligence, no? Or do agency board members close ranks when what might appear to be negligence occurs? I presume it is only the training agency itself that can verify the victim's training certification and records and that no-one from the outside can.

The agencies don't conduct accident investigations.

 

[St John the Diver]

Especially if the divers were out of everything except dil. But that's just a rumor.

If that's true, it just reinforces my belief that 10/50 is stupid gas. The only reason it exists is because any idiot can mix it. For depths where about 50% helium is adequate you can have a surface breathable mix, and when 10% 02 is actually needed 50% helium isn't enough.

I'd have been using 18% there without a doubt. It's why I bank 18/45

When we run 10% we are up at 60% on the helium.

Save a minute mixing, cost a life eventually.

Paul Blanchette died that way.

 

[TotDoc]

I see why people use very hypoxic dil on a rebreather, though - at those depths, 18% would already give you 1.4 pO2 at max depth of 220. If you are needing to use your dil to flush a high pO2 problem, you're going to have a tough time pushing the loop pO2 down quickly.

As an additional issue, I am certified through TDI, and they state a max pO2 of dil at working depth to be 1.3, so really I'd need less than 17% to be within standards for that dive. It's all splitting hairs, really...but 18/45 would not technically be an option for that dive based on standards for my organization.

Another standard (again - just for my TDI cert, not sure about someone else) is that the END can't exceed 100 feet, so 45% He at 220 wouldn't fly either, but 50% would.

That said, it would be a weird situation to have to ascend with no O2 onboard, and no bailout O2. If a hypoxic loop due to unavailable oxygen really was the cause of this accident, there was complacency with more than just the ease of mixing the gas...

 

[LandonL]

Having a max pO2 of 1.1 for the dil would be better, and i believe recommended, than trying to push down a high pO2 with a 1.3.

 

[Wookie]

I would have provided 16/50 for that dive, so the oc folks could dive the same mix.

But I understand why they were on 10/50. As stated, it's easy to bank.