44 replies to this topic

[ScubaDadMiami]

I haven't thought through all the trade-offs but is it possible to wear a full face mask with a rebreather?

Yea - a number of folks are vocal advocates of FFM in response to OxTox convulsions - as I understand it they too have their own sets of complications...

FFMs often add a larger area of dead space, causing one of the main things that a CCR is designed to avoid: CO2 build up. There are some that are designed better than others to minimize this.

Hyperoxia is a real danger on CCR if there is an equipment failure or diver error. However, there is an avoidance remedy for this, and this is one of the drills that I practice frequently. On open circuit, one could use the wrong mix or breathe from the wrong tank. There are avoidances for this. Each type of gear has its issues that require a diligent diver.

[Diverbrian]

Like SDM, once I get onto CCR and out of classes, I figure that I will be diving solo with it. We don't have many CCR divers up here and I don't feel like hunting for dive buddies. If something goes wrong down there, it will be my fault in some way, shape, or form.

I am one of the anal retentive types that would get along decently with a rebreather. But, I also plan to be set-up to rescue myself if something goes wrong. I also plan to keep in mind what went wrong in the other cases to keep it from happening to me.

Hopefully, I will be taking my CCR with my regular dive buddy and that will give me someone available to dive with when I dive the eastern Lakes and the St. Lawrence.

[matts1w]

So many people are getting hurt on on CCR....

Perhaps we should call foul with:

*the training curriculum
*the instructors
*the training agencies

Seems to be the trend around these boards lately.

[Diverbrian]

So many people are getting hurt on on CCR....

Perhaps we should call foul with:

*the training curriculum
*the instructors
*the training agencies

Seems to be the trend around these boards lately.

When the type of equipment is a bit more unreliable than OC, you need to be on your toes for Mr. Murphy. If you want a minimum of types of issues, I would recommend staying with OC. While OC doesn't provide you with the number of bailouts that CCR does, it doesn't provide you with all of things that can go wrong.

I was told that the key is in the training text that I bought was the first statement that if you don't don't WHAT you are breathing if you are on a RB then you are doing something severely wrong. The difference that we pay attention on OC to HOW MUCH gas that we have left but are certain of it's content (if we followed our protocols and blended/analyzed/ and marked it).

On a CCR, you have the gas between the unit and the bail-out bottles, but you don't have quite the certainty of it's content until you look at your handset of what is in it. It is that concept that causes trainers to tell new CCR that they are basically starting over on their dive training.

I plan to be on a CCR when time/money budget allows me to do that. But, I am a realist about the caution required to safely operate a CCR.

The fact of the matter is that the technology allowing us to take RB deeper is relatively new as compared to OC. Unlike OC, we don't have quite so many lessons "written in blood" yet to give us a better indication where we are safe and where we need to back away from the lines. Until then, the trainers and agencies will do the best that they can.

[PerroneFord]

So many people are getting hurt on on CCR....

Perhaps we should call foul with:

*the training curriculum
*the instructors
*the training agencies

Seems to be the trend around these boards lately.

This is a HUGELY unpopular stance to take, but you wouldn't be alone in taking it. There are clearly some RB instructors out there that are dicey. But as with OC, there are a number of divers showing up for training that simply are not prepared. The pressure to certify a diver with a RB is somewhat higher than just an OC BOW diver. The student now has a unit. Which means they've spent $4500-$20000 for it. They are obviously reasonably competent divers, or they probably would have not gotten that far. But you can't certify "safe attitudes".

In a well publicized action, one of the most popular rebreather manufacturers basically nullifed ALL instructors on his unit unless they came to his headquarters and took instructor training from him. This did NOT go over well with many, as you could imagine. But he was VERY worried about quality control in the instructor training.

Unlike OC, there are no RB training agencies. What you have is OC agencies who teach RB specialties. IANTD is a popular one. Apparently TDI is trying to get there. This sets up some very interesting liasons and bedfellows.

SDM is lucky to have a very good RB instructor. There are some around. But like OC, many people don't look for solid instructors. They look for a place to get certified. And this is a recipe for trouble. I've seen both scenarios play out, and I've seen the difference in the diver's it creates.

Most know that I deviate from GUE/DIR in that I do support CCR diving, but GUE only supports SCR. The idea of plugging in a KNOWN mix has a certain appeal. No setpoint issues, no electronics issues, being able to breathe the tanks off the loop, etc.

I don't know sometimes...

[matts1w]

This is what I respect about you, Perrone. You are consistent and your logic is always very solid. Eventhough we do not really agree on some things, I always enjoy reading and considering your viewpoint.

So many people are getting hurt on on CCR....

Perhaps we should call foul with:

*the training curriculum
*the instructors
*the training agencies

Seems to be the trend around these boards lately.

This is a HUGELY unpopular stance to take, but you wouldn't be alone in taking it. There are clearly some RB instructors out there that are dicey. But as with OC, there are a number of divers showing up for training that simply are not prepared. The pressure to certify a diver with a RB is somewhat higher than just an OC BOW diver. The student now has a unit. Which means they've spent $4500-$20000 for it. They are obviously reasonably competent divers, or they probably would have not gotten that far. But you can't certify "safe attitudes".

In a well publicized action, one of the most popular rebreather manufacturers basically nullifed ALL instructors on his unit unless they came to his headquarters and took instructor training from him. This did NOT go over well with many, as you could imagine. But he was VERY worried about quality control in the instructor training.

Unlike OC, there are no RB training agencies. What you have is OC agencies who teach RB specialties. IANTD is a popular one. Apparently TDI is trying to get there. This sets up some very interesting liasons and bedfellows.

SDM is lucky to have a very good RB instructor. There are some around. But like OC, many people don't look for solid instructors. They look for a place to get certified. And this is a recipe for trouble. I've seen both scenarios play out, and I've seen the difference in the diver's it creates.

Most know that I deviate from GUE/DIR in that I do support CCR diving, but GUE only supports SCR. The idea of plugging in a KNOWN mix has a certain appeal. No setpoint issues, no electronics issues, being able to breathe the tanks off the loop, etc.

I don't know sometimes...

[PerroneFord]

This is what I respect about you, Perrone. You are consistent and your logic is always very solid. Even though we do not really agree on some things, I always enjoy reading and considering your viewpoint.

Consistently flawed?!

I just try to look at this stuff from a pragmatic standpoint. Despite how we might dance around the issues, we are ALL tempting fate when we strap on gear and head below the water.. even in a pool. We accept that and go do what we love. If we die, it's likely no one's fault but our own. It's really that simple.

There are lots of people here and elsewhere with a TON more experience and knowledge than me. I am pretty new to this. I appreciate people taking me to task on stuff when I am wrong. I learn from it, and I'm humble enough to admit in public when I am wrong.

And my opinions are frequently abrasive and occasionally stupid. Goes with the territory.

Thanks for your kind words.

[peterbj7]

On the original topic, I like to dive CCR solo, and have made a number of 2.5 - 3 hour solo dives here in the 130' - 170' range. I don't regard it as intrinsically risky so long as I am properly equipped and thinking clearly. I think the underyling cause of high CCR fatalities is diver complacency. Most CCR divers are pretty experienced, and it is all too easy for people experienced in any sport to think at a subconscious level that "it won't happen to them". My CCR instructor is the same as SDM's and he teaches that complacency kills. He's mainly teaching CCR these days, but that philosophy applies to any diving.

As to the two CCR deaths that have been discussed here at some length, Zak & Rob, both used to teach at my shop and I did many dives with each of them. As far as I am aware, Zak did knowingly dive with a defective unit and paid the price, though there has been a complete clamp-down on information. Zak was a very popular diver and instructor (he was a PADI CD) who took great care with others' lives, but when playing could be a bit reckless about his own. His death was an awful shock but I can see how it could have happened.

Rob's death remains a complete mystery. Apparently his mouthpiece was out of order, but anyone who knew him knew he was an extremely careful and thoughtful person in everything he did, so the mouthpiece irregularity sounds odd. Again so far as I know, he had only just entered the water for his third dive of the day, and his computer showed that he dropped almost immediately to 80' then shot to the surface. I don't know whether cause of death was drowning or something else, but I do know that as a commercial airline pilot he had regular and frequent very probing medical examinations that ought to have revealed any severe health problems he may have had. I don't think we'll ever know what caused this tragedy.

Edited by peterbj7, 20 September 2006 - 01:39 PM.

[PerroneFord]

Rob's death remains a complete mystery. Apparently his mouthpiece was out of order, but anyone who knew him knew he was an extremely careful and thoughtful person in everything he did, so the mouthpiece irregularity sounds odd. Again so far as I know, he had only just entered the water for his third dive of the day, and his computer showed that he dropped almost immediately to 80' then shot to the surface. I don't know whether cause of death was drowning or something else, but I do know that as a commercial airline pilot he had regular and frequent very probing medical examinations that ought to have revealed any severe health problems he may have had. I don't think we'll ever know what caused this tragedy.

Peter,

I cannot presume to second guess Rob's decision, but I want to ask you and the other CCR guys here a question.

On dive 3 of the day, if your RB required a field fix to the loop, would you dive that unit?

Agree with you about Rob's computer download. About the ONLY thing that makes sense was a loop flood (especially since he had tried to make a fix. But unless I am mis-remembering (I've done that once already) he bailed after closing the loop, and apparently dumped his weights. And apparently this was significant because he wore harness weights.

[ScubaDadMiami]

Hmmm. Where to start? How about with a real world example involving myself.

So, we are on this amazing Bahamas SD Live Aboard Trip. Awesome walls, some pretty pristene conditions and all of the things I dream about for my dives. It is probably the third dive of the day, maybe only the second. Everyone is coming off of a nice surface interval, and conditions are great for diving. Our plan is to do a drift dive, and we are going to enter the water in two groups of four.

We do put on our gear, and we do our pre-dive checks. The first people jump into the water, and it is time to stand up to go to the platform. I take one last look at my monitors as I am getting ready to stand.

Suddenly, one of my three oxygen sensors seems not to be providing a read out. I confirm this by looking at both the primary and secondary hand sets. Okay, what do I do now?

I have two fully functioning hand sets and my HUD. Two out of three sensors is good enough, isn't it? After all, we are only going to 80 feet anyway. I mean, if one more sensor fails, I can just bail out to open circuit, aborting the dive, right? So, what is the big deal if I do the dive?

Maybe I should not do the dive. Hey, but this will be an amazing dive, and I don't want to miss it.

I am standing at the crossroads.

My decision: I tell everyone to go ahead. I take off all my gear, break down the unit, and I change out a simple part. I put everything back together, put back on my gear, and I am in the water within 20 minutes. I still get a good half hour on the drift dive though I have surely missed out on some of the good stuff.

There are some people that would have done the dive. Don't believe me? It happens everyday. One of the frequent causes of CCR accidents and deaths: Diving with known equipment issues.

I have another theory. However, I can't say that this is fact. It's just my own belief.

ECCRs are great because people think that they are like a Ron Popeil device: "Set it, and forget it." It is like the autopilot of the rebreather world. The problem is that using automatic settings coupled with distraction and possible equipment failures can lead to hypoxia, a lack of oxygen. Then, add to this the lack of practice with regard to skills. Throw in a little mix of pushing scrubber limits and another no-no or two. The result can be fatal. Guess what? This also happens everyday except that many get away with it for many times. All it takes is once for you to get killed from taking these kinds of chances.

I fly my Optima on manual all the time. I think that I let it go on automatic a total of one time since I got the unit. Even then, I did so just to see what it would be like. Believe it or not, I actually prefer using it manually. So, I feel no loss by not going with the auto pilot setting.

Okay, I am fudging just a bit here. There are times where the current is moving so fast as I am trying to pull myself down the line that I will allow the auto to kick in so that I don't have to pull a hand away from the line to inject gas. (You can set it for auto at .7 but fly above this--such as at 1.0, in which case the computer will not inject gas unless you let the PPO2 drop to below .7.) However, other than having the auto setting for convenience at times like these, I stick with manual control always.

My belief is that this keeps the user actively involved in the process and operation. Constant vigilance becomes a habit. Sticking with the program about dos and don'ts on top of this will reduce the chance of accidents tremendously.

It is not solo diving that is causing these accidents. It is complacency, distraction and the feeling of "it's not going to happen to me" that is behind almost every accident out there. Equipment failures happen. However, there is a protocol for how to handle these events. Following the protocol will almost always work.

Notice how I used the term "almost." The fact remains that no system is perfect. When things go wrong on CCR, they can go very wrong. On the other hand, CCR offers many more options than does open circuit for a lot of bad circumstances. "For the diligent diver, closed circuit rebreathers are actually safer than open circuit scuba." Tom Mount

[PerroneFord]

Good stuff man. One of the reasons I thought I would go with a KISS if I ever got into doing this, is because you HAVE to fly it manualy. There are some limitations iwth the KISS though.

Now that the COPIS Meg is out... the game has gotten a bit more interesting. For giggles, I really want to try the Boros. I started to last week, but I'll wait.

Sometimes it SUCKS having the KISS, Boros, Optima, Meg, and Inspo, all easily at hand.

[ScubaDadMiami]

6Gill is diving a KISS. So, he can tell you more about it. They are built well, and they are simple. For the money, they are a great unit.

The Boros is very sophisticated. In some respects, it might just be too sophisticated. So many proprietary parts and such. It is also a huge beast. However, as long as it is functioning, it seems to be a good deep diving rig.

The Copis Meg is a good way to get started if you need to get the unit first so that you can upgrade the electronics later. (I like having the computer as a back up though. To me, it's just another redundancy.) Megs are built tough. However, I just don't like the hose routing on them. Too many places to get caught on wrecks IMHO.

I really love my Optima. Honestly, if anyone would offer to give me any of these units for free, this would be my choice. Simple yet sophisticated. Great for recreational and deep tech diving. The Extend Air Cartridge is also simple but super efficient.

[6Gill]

My point wasn't so much the depth, any depth of water is an issue when your face is submerged in it and you can't breathe.
.

The intresting thing with rebreathers is unlike scuba you have more time at depth then in the shallows to sort issues where as OC becomes more dangerous as you go deeper

Like SDM, once I get onto CCR and out of classes, I figure that I will be diving solo with it. We don't have many CCR divers up here and I don't feel like hunting for dive buddies. If something goes wrong down there, it will be my fault in some way, shape, or form.

I think this is where alot of the solo stuff begins...noone to dive with much like the early scuba days.

When the type of equipment is a bit more unreliable than OC, you need to be on your toes for Mr. Murphy. If you want a minimum of types of issues, I would recommend staying with OC. While OC doesn't provide you with the number of bailouts that CCR does, it doesn't provide you with all of things that can go wrong.

I don't think CCR is more unreliable but the issues one faces might overlap some OC stuff but it has it's own particular demons.As in scuba understanding the strenghths,wealnesses and limitations allows one to make choices(hopefuly the right ones)

Hmmm. Where to start? How about with a real world example involving myself.

Suddenly, one of my three oxygen sensors seems not to be providing a read out. I confirm this by looking at both the primary and secondary hand sets. Okay, what do I do now?

I have two fully functioning hand sets and my HUD. Two out of three sensors is good enough, isn't it? After all, we are only going to 80 feet anyway. I mean, if one more sensor fails, I can just bail out to open circuit, aborting the dive, right? So, what is the big deal if I do the dive?

My decision: I tell everyone to go ahead. I take off all my gear, break down the unit, and I change out a simple part. I put everything back together, put back on my gear, and I am in the water within 20 minutes. I still get a good half hour on the drift dive though I have surely missed out on some of the good stuff.

There are some people that would have done the dive. Don't believe me? It happens everyday. One of the frequent causes of CCR accidents and deaths: Diving with known equipment issues.

I have another theory. However, I can't say that this is fact. It's just my own belief.

ECCRs are great because people think that they are like a Ron Popeil device: "Set it, and forget it." It is like the autopilot of the rebreather world. The problem is that using automatic settings coupled with distraction and possible equipment failures can lead to hypoxia, a lack of oxygen. Then, add to this the lack of practice with regard to skills. Throw in a little mix of pushing scrubber limits and another no-no or two. The result can be fatal. Guess what? This also happens everyday except that many get away with it for many times. All it takes is once for you to get killed from taking these kinds of chances.

I fly my Optima on manual all the time. I think that I let it go on automatic a total of one time since I got the unit. Even then, I did so just to see what it would be like. Believe it or not, I actually prefer using it manually. So, I feel no loss by not going with the auto pilot setting.



My belief is that this keeps the user actively involved in the process and operation. Constant vigilance becomes a habit. Sticking with the program about dos and don'ts on top of this will reduce the chance of accidents tremendously.

To anyone wondering why this is an issues,with only two sensors working and you get two different readings how do you know which one is right?
The one I see up here is people pushing the scrubber life to the max trying to get every last min. out of it.The stuff is cheap,esspcially with all the money your saving on helium.

6Gill is diving a KISS. So, he can tell you more about it. They are built well, and they are simple. For the money, they are a great unit.

I write something but getting caught up after being away...

[NCCaveDiver]

I've been taking an interest in RNs....

Smart decision -- I like RNs too. They are always very sensitive and caring and they really know how to take care of a man....AND they work weird hours so there's always time to sneak away without them for a dive

[ScubaDadMiami]

I've been taking an interest in RNs....

Smart decision -- I like RNs too. They are always very sensitive and caring and they really know how to take care of a man....AND they work weird hours so there's always time to sneak away without them for a dive

There are male RNs just as there are female doctors. Don't forget about that!