Rebreather recommendations

[Capt Morgan]

A lot of people die whilst wearing the colour blue. So what?

Don't dive an ECCR while wearing blue ? ☺️

[gobfish1]

Training back in 1998 ,

TDI weekend rebreather course. I've been informed that the practical aspects of
this course consisted of a 1 hour pool session, a 45 minute dive and 1 change of scrubber sofnolime - this is on top of the usual lectures and theory. no blue underpants needed .

[notdeadyet]

Training back in 1998 ,

TDI weekend rebreather course. I've been informed that the practical aspects of
this course consisted of a 1 hour pool session, a 45 minute dive and 1 change of scrubber sofnolime - this is on top of the usual lectures and theory. no blue underpants needed .

I did the IANTD course in 1996. One day of lectures (started at 12, broke for lunch while the fat ☺☺☺☺ of a guru necked a 16" pizza to himself, finished at 4). Next day diving which involved phoning round all my mates to scrounge a set of kit because Britain's greatest living wreck diver pitched up with no kit (because the ☺☺☺☺ fully intended to not get in the water with the diver on the unit), and two hours in the pool. Where we shared one rebreather between six people. Oh yeah, he turned up late as well as he did in a bottle of gin the night before.

The card that I am most proud of

I laugh my cock off every time I see him on the telly on some Monty Halls shite.

[Janos]

Does rEvo not sell a CE MCCR ?

Fair point. Well made 👍

Janos

[Janos]

Mark - just because I disagree with you does not make it snide and undermining.

Quite right. What makes it snide and undermining is that you insist on playing the man and not the ball.

Again, thus type of faulty logic is so common that wise thinkers have given it a A fancy name

Janos

[Janos]

you have two (NDY and myself) with courses in 90s talking about current limiting.

I don't recall talk of current limiting befire Ammers raised it. Any chance you could post up a photo from the relevant page of the manual from your course in the 90s? It would help,settle the debate.

Janos

[notdeadyet]

I don't recall talk of current limiting befire Ammers raised it. Any chance you could post up a photo from the relevant page of the manual from your course in the 90s? It would help,settle the debate.

Janos

I don't know if it still exists but it was discussed on the Yahoo groups homebuilders forum in the early 2000's. I'd assume that it would also have been discussed on the NW Designs rebreather list at the same period. I am pretty sure I read something from Kevin Juergensen a very long time ago as to why 0.9 was chosen for the Mk15/16 setpoint which raised the concept of current limiting (ie it could be verified on the surface predive).

I remember it being talked about on my EAN course round 94 in relation to analysing high oxygen mixes and the way cells die from the top down. It may not have been given a fancy title but it was certainly known about and discussed.

As I understand it, it is not unusual behaviour for a galvanic cell so I don't see why it wouldn't have been known about.

But if you didn't know about it prior to one particular post then I don't know what to say. I guess it never happened and both Graham and I are making it up for shits and giggles.

Sent from my D5803 using Tapatalk

[Paul Evans]

I don't know if it still exists but it was discussed on the Yahoo groups homebuilders forum in the early 2000's. I'd assume that it would also have been discussed on the NW Designs rebreather list at the same period. I am pretty sure I read something from Kevin Juergensen a very long time ago as to why 0.9 was chosen for the Mk15/16 setpoint which raised the concept of current limiting (ie it could be verified on the surface predive).

I remember it being talked about on my EAN course round 94 in relation to analysing high oxygen mixes and the way cells die from the top down. It may not have been given a fancy title but it was certainly known about and discussed.

As I understand it, it is not unusual behaviour for a galvanic cell so I don't see why it wouldn't have been known about.

But if you didn't know about it prior to one particular post then I don't know what to say. I guess it never happened and both Graham and I are making it up for shits and giggles.

Sent from my D5803 using Tapatalk

I,ve contacted Kevin and asked for his input.

At the time a lot of things were being played down, training was..........interesting and communication pre bulletin boards quite snail like.

I remember talking to my instructor (Later time frame) but this was known about pre 2000's I seem to remember a long discussion about it with Leon and how far back it was actually known about.

Kev is normally up for thi type of thing so hopefully he,ll pop along.

[nigel hewitt]

I don't remember the phrase 'current limiting' early on but I remember a discussion of cells and how they failed from my training in 2001.
A cell failed "at the high end" first I think was the warning.
Watch for a cell "not keeping up" at the high setpoint or the virtually inevitable overrun if you switched up on the descent.

[notdeadyet]

I,ve contacted Kevin and asked for his input.

At the time a lot of things were being played down, training was..........interesting and communication pre bulletin boards quite snail like.

I remember talking to my instructor (Later time frame) but this was known about pre 1990's I seem to remember a long discussion about it with Leon and how far back it was actually known about.

Kev is normally up for thi type of thing so hopefully he,ll pop along.

I always wondered the part forums and bbs played. There seemed to be a big spike in non-English speakers at one point and I wondered if that was down to not having access to the same level of info.

I used to read a French forum and it was definitely not as well informed as RBW. Hard to believe Burgerworld was actually a good forum at one point before the Bundys took over

Sent from my D5803 using Tapatalk

[gobfish1]

I don't recall talk of current limiting befire Ammers raised it. Any chance you could post up a photo from the relevant page of the manual from your course in the 90s? It would help,settle the debate.

Janos

i cant remember when i heard the words current limiting,
but i do remember being shown how to test a cell when using agas analysers on my nitrox fills

was told to use 21 air then breath on cell to get 16 and if if possible blow some 100% oxygen over cell . that was 93/94
so about 11 years be4 i did noddy1

[ebt]

I recall ammers big crusade on current limiting. theres certainly no denying she highlighted the risk, but i certainly recall that the cell failure mode was covered when i first dabbled in nitrox in the 90's (ANDI, if anyone remembers them!).

I think its just a question of emphasis...

[heyydude]

Hey everyone... I'm just responding to Paul's request to pop on here about Current Limiting. I just got off the phone with Bill Elliott, who ran the old NWDesigns list to find out when we talked about this. I believe it was around '96 or '97.

Background: Using the old Mark 15/16 electronics, they were designed to maintain a Set-Point of .7 (Mark 15) and .75 (Mark 16). We wanted to run our Set Points out to 1.2 (civilian CCR divers led the way on this, BTW - I remember showing some USN EOD divers how to "trick" the Mark 16 to maintain 1.2 at the RB Forum in Redondo - within a few years, the USN came up with the "Mod 1" electronics which switched from .75 to 1.3 at depth) - anyway, I digress...

In order to adjust the system more accurately to maintain 1.2, I developed a system using an industrial air compressor filter housing, which had 2 Bendix Connectors at the top (Primary and Secondary), and a homemade O2 Sensor Isolation Board inside to mimic the function of the Horseshoe Board in the Mark 15/16. There was also a BC quick connect fitting at the top of this. Inside, there were 3 Winchester Connectors which plugged into 3 Oxygen Sensors (back then, we were using O2 Sensors made by Mike Iswalt in the kitchen of his home in Downingtown, PA - no shit). I had a Feet of Seawater Gauge which connected to this whole gizmo. Using Air, all you had to do was pressurize the sensors to the equivalent of 156 FSW, which would equal a ppO2 of 1.2. Tweak the potentiometers in the 15/16 electronics to give you the vaunted "O" on the 15, or the Steady Green on the 16, and voila, you were good to go...

Learned the hard way that O2 Sensors actually require Decompression one day, and decided to switch to using pure O2 and lower pressures (funny story, but just imagine popping the BC Inflator off the top of this pot without bothering to slowly decrease the pressure inside, opening it up and seeing three disemboweled Oxygen Sensors with their attendant KOH splattered all over the inside of the pot, dripping of death... lol...).

So - this eventually became the "standard" for testing our sensors - even when I started JMI - we used real sensors and subjected them to real ppO2 to verify that our electronics were reading everything correctly. But from the earliest days, I would notice that some sensors just "stopped" outputting mV no matter how much pressure they were put under. I wrote this up someplace and it was a topic of discussion all the way back to the Techdiver BBS days. I recall having a nice argument with a "Guru" at the time (there were only 5 of us on the planet diving Mark 15.5/16 CCR's back then, so someone had to be the Guru...), and he vehemently told me I didn't know my ass from a hole in the ground (a practice upheld by other great divers that continues to this very day), that "sensors can't be current limited"... Well, he is not amongst the living anymore, so I'll just leave it at that...

To Paul's question, however - I believe the USN went with .7 ppO2 more for the CNS aspects than anything else. Just like Helium was viewed as voodoo gas back in the day, Oxygen Toxicity was looked at as a much bigger potential problem than it really is. Everyone has been diving elevated ppO2's for decades now, and I don't think that CNS toxicity is nearly as big a factor in diving accidents than say, hypoxia, which we all know is much more dangerous and relevant.

I have some other things to say here, but won't clog it all up in one post.

Kevin Juergensen
Juergensen Marine, Inc.

[Paul Evans]

Thanx for the input Mr J, unlike Mark's my handsets never dissolved

[Paul Evans]

I think its just a question of emphasis...

I agree, She sure shouted very loudly back then