New to rebreathers - what do you recommend based on this?

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I'm guessing you're not a cave diver. Do a search for Andrew Ainslie's dive that went bad in a cave. Staying on the loop is a BIG deal.
And if you take that back around to the original post, Southern California, travel, film work, there was no comment about being in the back of a cave. If cave diving was the expected use, the recommendations would be different to better match the intended usage. A great cave setup does not make it a great open water/ boat/ travel setup. Different designs for different peoples requirements.
 
I can't believe we're even having a discussion about whether flood tolerance/recovery is important and desirable, regardless of what kind of diving you do.

I'm not a cave diver either, but I damned sure think it's important that to have a unit that is easy to dewater and recover. "Screw it, I'll just bailout" is a distant second place to having a well designed unit.
 
Full disclosure, I am that buddy. I flooded the hell out of @kensuf ‘s loop during my MOD1 class. We were doing an ascent drill and when we got to the surface I “thought” I was closing his loop but I opened it all the way and popped the BOV out of his mouth. You could hear the gurgling of water going in and you could probably see my eyes from the check in shack at the Grotto. I remember Ken saying “You just flooded the $&%# out of my loop, so let me show you how we fix that.” We went back down and did a dewatering drill and then did 2 more hours on the loop. Flood recovery is good.

Looks like there's multiple examples then. Kelvin in Mexico had a friend flood his beyond belief and had pretty much no clue other than some gurgling.

I'm assuming the fix is the same as I was taught? Lean to the right and exhale hard(or do a dil flush) while pulling the lung dump? Or is there a different fix for more serious floods? That's what I was taught for a little gurgling in the hoses and told applies to bigger floods. Wasn't sure if there was something slightly more advanced for those big floods.
 
I'm guessing you're not a cave diver. Do a search for Andrew Ainslie's dive that went bad in a cave. Staying on the loop is a BIG deal.

I'd like to hear the story. I know his name and know it in reference to an issue, but don't know any of the details.
And I'm way too lazy to do a forum search
 
And if you take that back around to the original post, Southern California, travel, film work, there was no comment about being in the back of a cave. If cave diving was the expected use, the recommendations would be different to better match the intended usage. A great cave setup does not make it a great open water/ boat/ travel setup. Different designs for different peoples requirements.

Lol, people actually arguing that flood recovery not important. Whether it's a cave, wreck or reef, it's important. Lol,
 
I can't believe we're even having a discussion about whether flood tolerance/recovery is important and desirable, regardless of what kind of diving you do.

I'm not a cave diver either, but I damned sure think it's important that to have a unit that is easy to dewater and recover. "Screw it, I'll just bailout" is a distant second place to having a well designed unit.

He dives a revo, lol

No one wants to admit they bought wrong. It's okay. We get it. Lol.

After I found out that I bought wrong, I got certified on 4 more units within a few weeks. Then bought an Optima. I have no problem admitting the mistake. It's called adulthood. :)
 
I'm not a cave diver either, but I damned sure think it's important that to have a unit that is easy to dewater and recover. "Screw it, I'll just bailout" is a distant second place to having a well designed unit.

I dove a KISS Classic for years and logged over 300 hours on it during that time. You can't de-water it. While it is a weakness, I don't view it as that big of a problem for someone diving in openwater. If all I dove was in the ocean, I wouldn't cross the Classic off my list of CCR's simply because it can't be de-watered.

I'm assuming the fix is the same as I was taught? Lean to the right and exhale hard(or do a dil flush) while pulling the lung dump? Or is there a different fix for more serious floods? That's what I was taught for a little gurgling in the hoses and told applies to bigger floods. Wasn't sure if there was something slightly more advanced for those big floods.

Lean left and get your hip down, not right. The exhale counter lung needs to be lower then the rest of the loop so you can flush the water out while doing the DIL flush. BTW, the Fathom is only good for de-watering up to the point that the exhale counter lung is full. Once it's full, you're flooding the can and there's no easy way to recover from that.

If having the ability to 100% de-water a unit was the overriding factor in choosing a CCR, then everyone would be diving an SF2 or PSCR/RB80/Tres Presidentes. True story, I COMPLETELY flooded an SF2 as a test, like loop out of my mouth, mouthpiece up, shaking every last bit of gas out of the unit. I then de-watered it, stayed on the loop, and went for a 150 minute cave dive. There's nothing that is more flood tolerant than that unit.
 
I dove a KISS Classic for years and logged over 300 hours on it during that time. You can't de-water it. While it is a weakness, I don't view it as that big of a problem for someone diving in openwater. If all I dove was in the ocean, I wouldn't cross the Classic off my list of CCR's simply because it can't be de-watered.



Lean left and get your hip down, not right. The exhale counter lung needs to be lower then the rest of the loop so you can flush the water out while doing the DIL flush. BTW, the Fathom is only good for de-watering up to the point that the exhale counter lung is full. Once it's full, you're flooding the can and there's no easy way to recover from that.

That's what I was taught
 
I'm guessing you're not a cave diver. Do a search for Andrew Ainslie's dive that went bad in a cave. Staying on the loop is a BIG deal.

Is this the Running Out of Gas incident that was posted in NACD journal Vol 42 in 2010?

Does anyone have an electronic copy?
 

How Much Gas is Enough? Running on “Empty”

By Andrew Ainslie


I just had a rude awakening after a dive recently that has made me re-evaluate my attitude to gas management, and my ability to handle emergencies rationally. I thought that I’d write the case up as a short article, in the hopes that it will make others reconsider what constitutes adequate reserves, and to recognize the sort of mental spiral that almost killed me recently.

On my last trip to Florida, I decided to push an infrequently dived section of a cave section with a new sidemount rebreather setup that I had been playing with. While this is not the time to talk about the errors that I made in that configuration, it turned out to not be the right configuration for the task. At approximately 4800 feet of penetration, I tore a hose on the rebreather, instantly wetting the scrubber and flooding the rebreather to a level that made it fairly unusable. At that point, I had what I felt would be an outrageous amount of gas – I had a scooter, twin 85’s overfilled to 3600 psi in a sidemount configuration, a stage at 4000 feet, and a stage at 2000 feet. Under ideal conditions, a single one of those 85’s should have gotten me out.

My head, however, had different ideas. It took me approximately 10 minutes to get back through the restriction that I had just spent 10 minutes getting through in the other direction – and I really mean 10 minutes, I verified it afterwards on my computer log. During that 10 minutes I ultimately ended up completely removing one of the 85’s and pushing it ahead of me, then half removing the other 85 and pushing it ahead of me as I scrabbled behind it. The puffing and panting, together with my mounting concern, had my SAC up to an outrageously high level. By the time I got back to 4000 feet, I had emptied one of my 85’s – that’s over 100 cubic feet of gas in under 800 feet of cave, swimming with heavy flow assisting me. I was shocked when I saw the gauge so low – I hadn’t even considered swapping tanks yet, and I’d emptied one!

I went onto the second 85, attached my stage, and started heading out. I lost concentration at one point, and drifted off the “main” line (which is a white line) onto a side line, without noticing that I’d made a jump. This line led me almost immediately into a really low section of cave. I, together with my rebreather, 2x85’s and an 80, almost immediately got funneled into a mud-bottomed restriction that I couldn’t get past. My rapidly worsening mental state led me to try to force my way past the restriction, instead of slowing down and trying to work out what was going on. In the process, I created an outrageous mess, with a silt-out so bad that I now lost this new line. I finally stopped moving, and waited for what felt like an eternity (but was probably about 5 minutes) for the silt-out to subside, while I shone my light around, until to my huge relief, I found the line again. By now, my mental state was extremely poor, I was no longer thinking logically, and my SAC rate was beyond horrible.

Back on the line, I came to a restriction around 3500 feet that requires one to turn sideways when in a sidemount configuration. I turned on my side and squeezed halfway through when I felt my reg start to breathe hard. My immediate reaction (which turned out to be wrong) was that I had just finished my second 85 – that’s over 200 cubic feet of gas in just 1300 feet with flow! I stopped pulling through, moved backwards until clear of the restriction, and deployed and went onto my stage, now seriously concerned about my ability to get to my second stage at 2000 feet – i.e. another 1700 feet ahead of me – with no backup source of gas. I thought that I was now running on a single tank of gas.

At this point the cave starts opening up. I started focusing on breathing slower, and relaxing, as I rode my scooter home. At 2000 feet, I picked up my second stage with huge relief and clipped it off. Remember that at this stage, I thought that my primary 85’s were both empty. Given that, I should have deployed the second stage in order to have an alternate source of gas at the ready. I didn’t. I can only put this down to my deteriorating state of mind.

The next 1400 feet were pretty uneventful. But just 400 feet from fresh air, the inevitable happened – my stage started breathing hard. No problem, I thought, just deploy the other stage… but I just couldn’t get to it fast enough. I was fumbling unsuccessfully with the clip, realizing with mounting disbelief that I just wouldn’t be able to do it fast enough. I was about to drown less than 400 feet from the exit, with an untouched stage on me! Rapidly running out of options, I did the only thing that I could think of – I went back onto the flooded loop, hoping to get enough breaths out of it to finish deploying the stage. It was with incredible relief that I found that I could breathe through the gurgling loop, and that the now soaking wet scrubber wasn’t yet putting out nasty enough fumes to be unbreathable. I really do believe that if it had been unbreathable, I would not have been here today to tell this story – even though I had huge amounts of unused gas on me. However, I got lucky, and within a minute I deployed the stage, and was once more breathing from a good source.

By now, I was mentally a complete wipeout. I headed out breathing that last stage, just hoping that there wouldn’t be yet another problem, as I really believe that I no longer had the mental capacity to deal with it – I was mentally drained. It had completely freaked me out that I had almost drowned only a few hundred feet from the exit, and there was nothing rational about my state of mind. Less than 10 minutes later, finally breathing my oxygen, I lay in disbelief at how badly the dive had gone, and how lucky I was to be breathing, alive, and able to exit. After about an hour of deco, I surfaced to a silent, dark summer’s night, very happy to be breathing uncompressed gas.

When I had removed all my gear, I started doing a post mortem. The first big shock was that I actually had 1500 psi in one of my 85’s! What I had assumed was an empty tank in the restriction at 3500 feet was merely a rolled-off tank. I simply hadn’t checked, in my panicked state. But the equally scary thing was, I had an empty 85, an empty 80, 1500 psi in the other 85, and 2000 psi in the second 80. I had gone through well over 300 cubic feet of gas to travel 4800 feet with the current, using a scooter for most of that distance. I’ve done 4000 feet into flow before using less than 80 cubic feet in the same cave, many times!

What had gone wrong? I remember writing once, that there is rarely such a thing as a real emergency in the caves. The key to surviving an incident such as the one that I had just encountered is to SLOW DOWN and THINK! That night, I did not follow my own advice. I repeatedly allowed myself to be conned into believing that I was running out of air, when in fact I had hours of reserve on me. I repeatedly neglected to check valves and gauges in my excessive zeal to exit the cave. And in my rush, I accidentally made a jump… silted out the cave to the point that I then lost that line… had a roll off that I misdiagnosed as an empty tank… and attached my last redundant source of gas without stopping to deploy the reg. That’s four major mistakes in a row that occurred from not slowing down and thinking, and each time, instead of realizing what had created the error and methodically fixing it, I allowed my mental state to deteriorate even further and then started moving ever faster, ever more carelessly, with a spiraling descent into a set of circumstances that really could have resulted in a drowning… while I had well over 100 cubic feet of available gas that poor planning made unavailable to me.

Put differently, it turns out that I’m not as rational as I thought. I actually do believe that I’m usually reasonably calm under pressure. But a very difficult 10 minute scramble through a restriction started a narrowing of my perception, and every problem after that moved me into an even more panicked, illogical state of mind until the truly inconceivably dumb move – not deploying my last stage’s reg – very nearly killed me.
What did save me? The answer is simple - huge gas reserves (and a bit of dumb luck). I had over 400 cubic feet of bailout gas on a dive that I had calculated needed about 100 under perfect circumstances. I needed every one of the 4 cylinders – admittedly because of an error of judgement on my part, but still, had I not had that second stage as well as two steel sidemount tanks (which seemed like insane overkill before the dive), I would now be dead. And the fact that a badly compromised loop gave me a couple of minutes of decent breathing gave me the latitude I needed to fix my idiotic error.
 
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