Why do you use a rebreather?

[Mr.X]

I'm looking into one for similar reasons. Since I shoot video there is an obvious advantage to being able to get closer without the noise from OC disturbing the things I'm trying to film.

I will second this. I shoot a lot of underwater video using ccr. Having a rebreather makes filming logistics easier, and at the same time a tad more interesting.

*Marine life swims closers and interacts naturally
*There is less bubble, or breathing noise to edit out
*Ambient sounds can be heard on tape - sometimes even muffled conversations
* Extended bottom possible

*Prep. time increases - this includes the camera & rig
*You have to monitor your PO2 carefully - A HUD & buddy are very, very important a cameramen become myopic when the shot is happening
* Slightly more drag vs. a single cylinder, or sometimes even doubles

In summary, rebreathers are a terrific tool to have as a videographer because it gives you a few more options that OC.

X

 

[silent running]

This is actually the only "good" reason that I have heard of, so far.

Hello nereas, not to sound contentious for the sake of it, but if we are going to qualify using an RB with the word "good", does that mean RBs are inherently unsafe and that any type of RB diving, baring scientific research, is more worthwhile/necessary than another?

As a "recreational" CCR diver, most of my dives accumulate less than 30 minutes of deco, are not in overhead environments and involve blending in with the scenery to have better wildlife interaction and the kind of maximum dive planning flexibility that CCR allows. And yet, I fail to see how somebody who wants to spend 20 minutes in/on a wreck at 300ft on a He mix to see the sights and get out of the water in the same 2 hours I will after watching sharks and other fish behavior in shallower water on air dil, is doing anything more laudable. We are both diving for our individual fulfillment and can share the experience with no one, other than through photography, albeit with different levels of risk.

But, if we are somehow going to accord greater importance to someone's dive plan based on risk, again baring scientific value, then a lunatic who does a bounce dive down 1000+ft using a deco program with no validation past 600ft and who claims to be only trying to achieve a personal goal, but who is also likely motivated by the notariety they will receive from the public, who don't know much about diving and think divers are just another type of adrenaline junkie, is that person somehow more noble than a diver who takes less risk?

I'm not a person who uses the phrase "It's all relative" very often, but I find myself miffed by the notion that any diving not funded by a non-for-profit organization advancing legitimate scientific goals, can be judged to have a higher value and thus more worthy of the risks associated with RB diving, than any other. Unless of course, all pretense is dropped and we admit that taking an extreme risk for the mere sake of it is just another way of avoiding a genital measuring contest.

BTW, I'm a novice tmix diver and have ambition to do more tmix dives in the future as my objectives dictate, and I got a CCR for the following reasons in order:

1) Better and more frequent wildlife interaction.

2) Maximum dive planning flexibility, both in terms of individual dives and the dive day.

3) Deco advantage of constant PO2 CCR diving.

I have enormous respect for any competent CCR diver who boldly goes someplace challenging and has a reasonable expectation of returning in good health. Just as I do for a CCR diver who focuses their attention differently, as I do, away from a primary concern for risk management in pursuit of objectives, and towards objectives that must be stalked, as hunters do... -Andy

 

[Mr.X]

This is actually the only "good" reason that I have heard of, so far.

Since you haven't used one ever...how would you know? Also, thanks for wishing me dead a bunch of posts ago.

X

 

[Chicago-Diver]

I don't currently own a CCR yet, but I am looking at them. I've tried the Optima and I really like it.

 

[nereas]

Hello nereas, not to sound contentious for the sake of it, but if we are going to qualify using an RB with the word "good", does that mean RBs are inherently unsafe and that any type of RB diving, baring scientific research, is more worthwhile/necessary than another?

As a "recreational" CCR diver, most of my dives accumulate less than 30 minutes of deco, are not in overhead environments and involve blending in with the scenery to have better wildlife interaction and the kind of maximum dive planning flexibility that CCR allows. And yet, I fail to see how somebody who wants to spend 20 minutes in/on a wreck at 300ft on a He mix to see the sights and get out of the water in the same 2 hours I will after watching sharks and other fish behavior in shallower water on air dil, is doing anything more laudable. We are both diving for our individual fulfillment and can share the experience with no one, other than through photography, albeit with different levels of risk.

But, if we are somehow going to accord greater importance to someone's dive plan based on risk, again baring scientific value, then a lunatic who does a bounce dive down 1000+ft using a deco program with no validation past 600ft and who claims to be only trying to achieve a personal goal, but who is also likely motivated by the notariety they will receive from the public, who don't know much about diving and think divers are just another type of adrenaline junkie, is that person somehow more noble than a diver who takes less risk?

I'm not a person who uses the phrase "It's all relative" very often, but I find myself miffed by the notion that any diving not funded by a non-for-profit organization advancing legitimate scientific goals, can be judged to have a higher value and thus more worthy of the risks associated with RB diving, than any other. Unless of course, all pretense is dropped and we admit that taking an extreme risk for the mere sake of it is just another way of avoiding a genital measuring contest.

BTW, I'm a novice tmix diver and have ambition to do more tmix dives in the future as my objectives dictate, and I got a CCR for the following reasons in order:

1) Better and more frequent wildlife interaction.

2) Maximum dive planning flexibility, both in terms of individual dives and the dive day.

3) Deco advantage of constant PO2 CCR diving.

I have enormous respect for any competent CCR diver who boldly goes someplace challenging and has a reasonable expectation of returning in good health. Just as I do for a CCR diver who focuses their attention differently, as I do, away from a primary concern for risk management in pursuit of objectives, and towards objectives that must be stalked, as hunters do... -Andy

To answer your specific question, about what do I mean by "good," for me good means a calculated analysis wherein it is determined that one risk outweights another.

In ScubaDadMiami's response, he has weighed the risks of the CCR unit against the risks of an O/C unit running OOA in a cave environment, and he has determined that the net benefit of the CCR is greater.

That makes perfect sense, logically. And coming from a Florida CCR instructor, I have no doubt that he knows what he is talking about.

You can thus use an approach like this one to go on to make a short list of the realistic and sensible justifications for utilizing a CCR, if you like. Some do, and some don't, as you can tell from the responses.

In the case of your own 3 responses, I would say that your replies are one-sided. You only speak of the benefits. And based on my definition, that is "not" good.

 

[WD8CDH]

In the old days, I used CCR for all of the above reasons. Now it's because the RB's that I use are lighter and so much easier to carry. .....sign of old age.......

 

[scubanimal]

While initially, the photo opportunities convinced me to shift to SCR (trial dive), once I began to dive it frequently, the warmth, lack of dry-mouth and longer no-deco times were a welcome benefit. Shortly there after not having to change out tanks between dives was nice. After shifting to CCR all those benefits were extended a bit. I had truly wonderful interactions with various marinelife, the long dive times (in warm water) were awesome and being able to stick around when all the OC divers left provided great opportunities.
Then I started thinking beyond recreational limits, the training was challenging and fun. I enjoy the challenge of planning the dives as well as the actual dives. Watching the OC folks having to plan for very short bottom times (10-15min) seemed silly after going through all the effort and expense of the dive. The CCR allowed me to plan dives that made more sense to me i.e. 30 min bottom times. NDL times are no longer the wall, just a planning note. My concern for having sufficient air is now focused on my bailout needs and is easy to calculate.

I've found the more I use my RBs the more I like them, the reasons vary, but except for the weight and extra prep time I truly enjoy it. There are risks, and I can not relax mentally nearly to the extent I could on OC, but then I don't need to, my breathing rate needs to stay higher anyway for an RB.

RBs are not for everyone, they have a long way to go before they can be trusted and relied upon to get you back every time. Its rare now for OC gear to break and require your buddy to get you back, that is not the case with RBs. So if you really enjoy the 'engineering' side and having to work a bit while diving then maybe this is something for you, if the concept of being anal retentive sounds like it would detract too much from your enjoying diving then maybe the technology needs to improve some before its a good option for you. But for me, I really love diving my RB.

 

[nereas]

In the old days, I used CCR for all of the above reasons. Now it's because the RB's that I use are lighter and so much easier to carry. .....sign of old age.......

This is the second really "good" reason that I have now heard.

And we have a lady diver (forgive my vernacular, but I am an old man, and old men talked like this when they were young, back when there were few lady divers) on our boat who does so for the same reason exactly.

She always comes alone with her CCR. And she sets it up at the far end of the boat, so she can be the last one into the waters, because she needs to breathe off it for 5 mins to ensure it is working properly before she goes in with it.

She also then eyes each of the rest of our O/C equipment, and the guy with the biggest twin tanks usually gets her nod of approval, and she then askes, "would you like to come diving with me?" Her inviting smile and flashing eyes are irresistible as were the ancient Greek Sirens.

Like a mermaid, she can stay down virtually forever with her CCR. And unlike an O/C diver, she does not need to be a 225 lb Greek Atlas to lift it.

 

[silent running]

To answer your specific question, about what do I mean by "good," for me good means a calculated analysis wherein it is determined that one risk outweights another.

OK, but how familiar are you with the risks associated with RB diving in general and how those risks are managed by each specific design? RB divers differ plenty about which designs are safest and which diving practices are most risky and which are not. IMHO, RB diving carries somewhat more risk than OC, but also has so many advantages that for a vigilant diver, they are safer. In my 750+ hrs on RBs, I have had only 1 potentially dangerous, self inflicted incident on an SCR. On the positive side of risk, I have done exploratory dives on CCR in difficult conditions that might very well killed me had I attempted them on OC. I have also made mistakes on CCR, like forgetting to turn on my cylinders, that would have almost certainly killed me if I was diving OC but were a minor problem diving CCR.

In ScubaDadMiami's response, he has weighed the risks of the CCR unit against the risks of an O/C unit running OOA in a cave environment, and he has determined that the net benefit of the CCR is greater.

Yes, and of course I agree with him, but other Florida cave divers, even some very experienced RB divers, disagree with him. Where in his post does SDM list the common dangers of RB diving? He only mentions the gas efficiency argument and leaves out the possibility of hyperoxia due to 2 faulty O2 sensors and CO2 hits, things which are not nearly as likely on OC and are some of the reasons given by other Florida cave divers for not using CCRs. I don't think SDM meant his post to stand for a comprehensive analysis of all the risk factors in CCR cave diving, but you seem to have, which shows how much you don't know about RBs.

Here's another fact that many people don't address when comparing OC tech and RB: Most OC tech accidents result from switching to the wrong gas, something highly unlikely on CCR. With an RB, you will always have at least one way to know what you are breathing and don't have to completely rely on labeling and rigging/cylinder placement, things which introduce that many more ways to screw up.

That makes perfect sense, logically. And coming from a Florida CCR instructor, I have no doubt that he knows what he is talking about.

Nothing personal towards SDM or you, but any thinking person SHOULD doubt what he's talking about, as I said above. Your opinion is not informed enough to make these kinds of statements, SDMs is, but I say this only because I've read enough of his posts to know he is familiar with opposing arguments. Until someone has heard all the arguments for and against RBs, properly understood them and has some experience diving them, I wouldn't take their opinion seriously. And while we're at it, I have heard CCR tmix instructors say things I know to be untrue and consider very dangerous. Which brings me back to the main point of my posting on this thread: The safety of CCRs is a highly debatable and thus, ultimately personal issue. IMHO, there aren't enough of us doing the same kind of diving to provide enough data from which to properly assess the exact level of risk involved in CCR diving.

In the case of your own 3 responses, I would say that your replies are one-sided. You only speak of the benefits. And based on my definition, that is "not" good.

So SDMs post is not one sided? Where does he list any of the risks of CCR cave diving? Other than the overhead environment, a CCR cave diver is exposed to the same general risks as any other CCR diver. Unless, of course, we are discussing whether a particular kind of non scientific CCR diving is more worthy of risk taking than any other, and thus "justifies" the use of one. They only non scientific justification for RB diving is the quality of experience you have using it and whether it's worth the risk and trouble. Either you are a competent, aware CCR diver who makes full use of their advantages, or you're in it for the novelty, which is the only "bad" reason I can think of. And I say that only because someone who is diving RBs just for the novelty is probably less likely to really learn the amount necessary to really understand both their own physiology and how their RBs function... -Andy

 

[ScubaDadMiami]

Every kind of diving has its risks. So does rebreather diving. You just can't eliminate risk while diving. If that is what you are looking for, stay out of the water.

On the other hand, with proper training and and following the protocols learned in that training, the risks of rebreather diving are minimized. In many cases, the risk is lower than when diving open circuit. As Tom Mount once stated, "[f]or the diligent diver, closed circuit rebreathers are actually safer than open circuit scuba." It is much more a question of the diver than the equipment.