Brad Horn on the rEvo

[Brad_Horn]

I don't know about a), but b) couldn't be further from the truth based on the cases I know about.

Great, look forward to seeing the accident analysis of each incident published at some point or at the very least, sufficient disclosed to positively rule out the rebreather's design.

and now, Brad, you are implying two similar (design related) failures, same time same day!

Richard, something is causing the fatalities on rEvo's! What the root cause is, I do not yet think anyone knows....
To answer your innuendo, personally I think it is something identical as opposed to "similar". But to confirm or deny any link to all the other rEvo fatalities, it would need formal accident analysis. In a pot with recording of the unmanned gas analysis from the mouth, off the units mounted on a manikin, in order to recreate the exact circumstances and conditions of the dive: inclusive of orientation, duration, gas, workload and temps. If that creates a condition where the loop is no longer safe to breath off, everyone will have an answer. NEDU did a great case study of this with their Ex19.

Ambulance chasing much? Personal agenda much? You are real good at innuendo.

No & Nope in this case, other than a curiosity of the root cause behind these rEvo fatalities! Lets see what the NEDU analysis determines, if that is where the units have both ended up. They do good work, per page 237+ https://www.diversalertnetwork.org/files/Tech_Proceedings_Feb2010.pdf

There is an internal black box recorder in the rEvo as well. However to date the (former) manufacturer hasn't been terribly cooperative in accessing and sharing the data for investigations.

A very undocumented feature! Where is it located, as all I thought the rEvo had in it as far as electronics go, is the galvanic O2 cells, temp sensors for the RMS if fitted and associated wiring....

 

[St John the Diver]

A very undocumented feature! Where is it located, as all I thought the rEvo had in it as far as electronics go, is the galvanic O2 cells, temp sensors for the RMS if fitted and associated wiring....

Embedded in the CANBUS hardware in the middle of the rig.

Good luck getting anything from it though.

The rEvo accidents are statistically the same as any other rig. I would be very circumspect about assigning anything more to it than hours used worldwide.

 

[Patoux01]

[rant=on]
Let's just remember that the list cited by @Brad_Horn is nothing more than trash made by himself so he could sell his non-existent rebreather. Want a proof? Just search "Wes Skiles" in there and see what it reads. Then read what happened with the Wes Skiles case in court (where, interestingly, Brad & friends were fairly active, trying to prove the ccr was at fault), and the result was: the ccr was not at fault. Also, even if his signature reads of a brand, I'll add that the rebreather Brad tries to sell is literally non-existent, I know of only one that has been delivered, and it is an oxygen ccr, not much that can go wrong with those.

Sorry for putting this here in a non-related thread, but since I saw the list spit up some 5 pages ago, and there are a lot of novices reading this thread, this clarification seemed necessary to me.

So, are you gonna update that list, or are you simply going to shove it up your *** instead of trying to put it down our throats? It reads "updated 20th january", yet Wes Skiles is still cited as "rebreather design fault".
[rant=off]

 

[Brad_Horn]

and it is an oxygen ccr, not much that can go wrong with those.

Oxygen CCR or mCCR, for use to 100m; which is readily comparable to the rEvo mCCR units.
Quite a lot can go wrong with an oxygen only CCR, noting that forms the basis for every single CCR on the market: be it an o-ring that can be left off for CO2 bypass, poor ADV, poor WOB, lack of means to bailout, poor CL design or wrong choice of materials and the list goes on....

It reads "updated 20th january", yet Wes Skiles is still cited as "rebreather design fault".

Based on the sole accident analysis done on that eCCR my understanding remains that root cause is water blocked oxygen cells causing hypoxia. Waterblocked due to the horizontal nature of the EAC causing the scrubber to trap water like a swimming pool and at times flood the face of the oxygen cells. Resulting in the electronics reading a totally different PPO2 to that which the diver was breathing. Both electronics and cells on the unit, before, during and after, were found I understand to be working exactly as their design specified.

Quite happy to be shown evidence from analysis of the unit in question to the contrary. If valid, I will happily forward on to DL to get the list updated. Especially noting the circumstances seem to match quite closely to a number of the other fatalities on the same unit. The Skiles court case I understand focused solely on liability and not the actual root cause behind why the diver passed away: on ascent from a shallow dive in near perfect conditions, on an apparently perfectly good eCCR that was not alarming and had undergone a very thorough written checklist procedure by its diver, immediately before being dived. Seemingly something that could have happened to any diver, no matter how they got hold of the unit or were trained to dive it.

 

[Wookie]

I believe you were shown evidence. In a US court of law. When Mr. Concannon inserted it your rectum and it may still be there for all I know.

Your opinion stinks, has been discounted, and you have no place in a discussion where rebreathers are the topic.

 

[oldschoolto]

I believe you were shown evidence. In a US court of law. When Mr. Concannon inserted it your rectum and it may still be there for all I know.

Your opinion stinks, has been discounted, and you have no place in a discussion where rebreathers are the topic.

Tell us how you really feel Frank....
jim..

 

[The Chairman]

Split from => Alligator Reef diver [Rob Stewart] missing - Florida Keys

Have fun, guys!

 

[kelemvor]

@Wookiee Have any more info on that case like case# or who was suing who and what court? I'm curious enough to pay a few bucks for a transcript...

 

[cerich]

had undergone a very thorough written checklist procedure by its diver,

That would be the diver not trained on the unit and also with a pharmacy in his blood? Yeah, whatever.

 

[kelemvor]

and it is an oxygen ccr, not much that can go wrong with those.

Oxygen CCR or mCCR, for use to 100m; which is readily comparable to the rEvo mCCR units.

I'm a rebreather laymen so I had to look this one up. To save others time and trouble, it appears there is a vast difference between an "Oxygen Rebreather" and a modern "SCR Semi Closed Circuit Rebreather" or "CCR Closed Circuit Rebreather" used in scuba diving.
Source: Rebreather - Wikipedia It's a VERY long article (as wikipedia articles go) so I'm including relevant excerpts:

Oxygen rebreathers

This is the earliest type of rebreather and was commonly used by navies and for mining rescue from the early twentieth century. Oxygen rebreathers can be remarkably simple designs, and they were invented before open-circuit scuba. They only supply oxygen, so there is no requirement to control the gas mixture other than removing the carbon dioxide.[19]
Oxygen feed options
In some rebreathers, e.g. the Siebe Gorman Salvus, the oxygen cylinder has oxygen supply mechanisms in parallel. One is constant flow; the other is a manual on-off valve called a bypass valve; both feed into the same hose which feeds the counterlung.[11] In the Salvus there is no second stage and the gas is turned on and off at the cylinder.

Others such as the USN Mk25 UBA are supplied via a demand valve on the counterlung. This will add gas at any time that the counterlung is emptied and the diver continues to inhale. Oxygen can also be added manually by a button which activates the demand valve.[20]

Some simple oxygen rebreathers had no automatic supply system, but only the manual feed valve, and the diver had to operate the valve at intervals to refill the breathing bag as the volume of oxygen decreased below a comfortable level.

Closed circuit mixed gas rebreathers

Military, photographic, and recreational divers use closed circuit rebreathers because they allow long dives and produce no bubbles.[25] Closed circuit rebreathers supply two breathing gases to the loop: one is pure oxygen and the other is a diluent or diluting gas such as air, nitrox, heliox or trimix.

A major function of the closed circuit rebreather is to control the oxygen partial pressure in the loop and to warn the diver if it becomes dangerously low or high. Too low a concentration of oxygen results in hypoxia leading to unconsciousness and ultimately death. Too high a concentration of oxygen results in hyperoxia, leading to oxygen toxicity, a condition causing convulsions which can make the diver lose the mouthpiece when they occur underwater, and can lead to drowning. The monitoring system uses oxygen sensitive electro-galvanic fuel cells to measure the partial pressure of oxygen in the loop. The partial pressure of oxygen in the loop can generally be controlled within reasonable tolerance of a fixed value. This set point is chosen to provide an acceptable risk of both long-term and acute oxygen toxicity, while minimizing the decompression requirements for the planned dive profile.

The gas mixture is controlled by the diver in manually controlled closed circuit rebreathers. The diver can manually control the mixture by adding diluent gas or oxygen. Adding diluent can prevent the loop gas mixture becoming too oxygen rich, and adding oxygen is done to increase oxygen concentration.

In fully automatic closed-circuit systems, an electronically controlled solenoid valve injects oxygen into the loop when the control system detects that the partial pressure of oxygen in the loop has fallen below the required level. Electronically controlled CCRs can be switched to manual control in the event of some control system failures.

Addition of gas to compensate for compression during descent is usually done by an automatic diluent valve.

@Brad_Horn or @Patoux01 Can either of you fill me in on how someone might scuba dive with an Oxygen rebreather? Unless I misunderstand, you're going to be at a pp02 of 1.0 at the surface and will likely tox out with any substantial death. Am I wrong, or is Brad's product not really an Oxygen Rebreather?