One dead, one missing (since found), 300 foot dive - Lake Michigan

[rjack321]

There are videos Jim Winn posted online on both the Emba and Thomas Hume wrecks in late May/early June that show the scooters.

If you don't want to work hard at 300ft (a wise move from both a gas loading perspective and a Co2 perspective) then a scooter is a good idea.
On the negative side its one more thing to go wrong - flooding and going super negative while on ascent might be the worst possible case. But triggers can stick on and a myriad of lessor issues are certainly plausible.

 

[infieldg]

If it's a Shearwater it will indicate on display, with a total lack of offset weight motor (vibrator) or audible alert. No idea why they left those off??

Yeah that infuriates me - given that my Teric does - or DID, til I sold it to pay the rent lol - either they think those features would discourage TECHNICAL divers from checking their TECHNICAL computers (unthinkable for your RB guys!), but anyone who dives with a dress watch NEEDS a tap on the shoulder, or "WHOOP WHOOP! HIGH PPO2! PULL UP!" doesn't fit on a Teric screen

 

[telemonster]

 

[dewdropsonrosa]

I don't appear in-frame, but I'm in (above, to be accurate) that video.

I was a little chilly and a little narced on my way up the line, and watching them zoom around the bow at top speed (2:20) made me giggle through my reg. It looked like they were having great fun, and I'm sure that they were. I think about that moment a lot when I come back to visit the thread.

 

[Dusty123]

I bet they had that gopro rolling on that scooter in the accident

 

[TrimixToo]

If you do a CESA from 300ft you are going to die. Period. There is no other outcome.

OC gas for that depth is 12/65 or 10/70. You can't breath that on the surface. ppO2 in a CCR will drop and become unbreathable as well. But hypoxia is not really the problem since you by definition have a substantial decompression obligation. Even if you had a chamber on the deck of the boat unless they blow you down to 165ft (Navy Table 4) you are going to die. If they get you back down with a Navy Table 4 immediately - there's a chance you might live - a chance.

Tech divers doing 300ft dives have to solve their problems in the water.

Yup.

 

[John C. Ratliff]

Telemonster,

They surely do look like they are having fun in that video.

Thanks for the video.

SeaRat

 

[TheAquaticApe]

Bottom temp on the Home 2 weeks ago was 39 so I’d say somewhere in that neighborhood. Pretty cold.

 

[cerich]

If you do a CESA from 300ft you are going to die. Period. There is no other outcome.

.

research submarine escape, they are cesa's. mind you the bottom time is not generally what you will see in tech diving. It could be close to someone who bombs the floor and then does a
Polaris

 

[jfe]

I’m not trying to be snarky, and I am humbled by diving a CCR. I don’t take anything for granted, and I am always trying to learn and to improve the safety of my protocols............................ I mean, I’m sure that there are some truly unavoidable accidents, but most of what I read about are failures of process, not of gear. Of course you can have gear failures, that’s why we carry bailout. But a big part of training is monitoring for those...

I’m just saying that like most choices, you are balancing risks and benefits...

John, a CCR does not present the same need for an ESA as OC does. On a 300' plus tech dive, OC and CCR divers would not even contemplate an ESA. there would be gas sharing (OC) or separate bailout (CCR) protocols in place.

Even then, a CCR doesn't present a "loss of gas" situation like OC would. If you are out of diluent, an ascent is normal since diluent is not needed for ascent. If you are out of O2, then a PPO2 drop would occur on the ascent but then you would be bailed out onto an OC tank, or even a second CCR, or you could plug in your OC deco tank into the unit to manually add O2, or you could breathe your diluent in SCR mode until it got too lean, or....

There are many ways to deal with issues in a CCR but ESA is almost never one of them.

So here is the part I'm totally missing in all of these discussions. A dive to 300 FSW requires a significant amount of bailout gas consideration, being OC or CCR. I have not in any report seen any mention of whether they were or were not carrying bailout cylinders, however their experience level would suggest they had, or if it's been deployed and used or available but not touched. If, and pure speculation, they did not have the necessary amount and mix of bailout gas, why were they allowed to dive? If they had, how come 2 divers miss the opportunity to bail out, it seem rather strange since the 1st protocol for CCR emergency is to bail out in case af critical failure. Did they plan on shared gas emergency and somehow the bailout failed. If the planning was shared emergency gas as a four diver team, did every member carry an amount for save bailout at the MOD.
I do realise that in a panic or when hypoxia / hypercapnia start setting in you can totally miss the opportunity to bail out, much less be coherent and doing a controlled ascent before you become so positive and have a runaway ascent (looking like a ESA to others), also totally plausible imo.

Just my 2c worth thinking about what is not said.