Should I try a rebreather?

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Modern rebreathers aren't that hard to use, 15 minutes explanation is enough to handle the basics, that is just few points: what's and how to operate the DSV (10 seconds), pressure compensation with the nose/side mouth (breath out using your nose to relieve the pressure) (after you do it a couple of times, it'll be natural), switch to the bailout if you feel something is wrong. That's it (you may add the diluent and o2 manual injection.. however isn't necessary for the simple dives).
You do your dive at a depth where the po2 isn't an issue, so there isn't much to monitor, and you enjoy your dive like you would normally do (and it would be impossible to not love it IMO...).

Doing a proper course (that involves the preparation, the theory, how to operate a CCR, how to maintain it, and all the bits) is another matter... but that's not the case of the op. There's nothing to be scared about, it's not that you gonna die in 12 meters, or at least the risk isn't higher than doing it in open circuit, even with only 20 dives.
 
it's not that you gonna die in 12 meters, or at least the risk isn't higher than doing it in open circuit, even with only 20 dives.
A poorly monitored rebreather will kill you way shallower than OC ever would. A failed OC first stage at 12m? Buddy, then CESA in order of desirability. You will know because it will get way hard to breathe.....

A failed O2 first stage on a rebreather at 12m? Closed, you quietly pass out and die from hypoxia. Failed open? While you're trying to fix or figure out your buoyancy issues arising, you end up on a PPO2 of 2.2 which may or may not ruin your day.

IF you KNOW that something is wrong, and what to do, then sure, 12m is safer than 50m, but the insidious part of rebreathers is that they give you new ways to kill yourself while blissfully unaware anything is wrong.
 
I've seen rebreathers in my local dive shop, and was asked about them on the survey for this site, but I've never used one before, I mainly use the standard regulator system with a yoke valve. Would a rebreather make my dives last longer or could I go deeper? Would it be easier to use than a regulator? What level of certification do I need in order to use one? And would I need to know how to use one if I'm going into the Marine Biology field?
Thanks in advance!
A few years ago, I was seriously researching rebreathers with the intent to buy/use one. Before I made a decision on what unit to get, I saw several rebreather fatalities reported. Generally they get chalked up to "operator error" and by operators that were FAR FAR better divers than I. Initially, I thought I'd go halfway with an SCR first to "test the waters" so to speak. Then everyone on scubaboard told me that basically an SCR has all the risk of a ccr with little benefit over OC. Grudgingly, I decided that it just wasn't in my long term best interest, and I gave up on the idea. Of course to play devil's advocate, those operators were also doing dives FAR outside the bounds of any dive I'd plan to do for the foreseeable future. Who knows? I don't, and I am still strongly of the opinion that I should not buy one myself.
 
(The OP is a high school junior interested in Marine Biology, from her profile. And OP, I only mention your age as rebreathers are rather advanced diving with increased risk.)

I can likely answer the Marine Bio part, at least until you're a graduate student. You don't need a rebreather. You do need to be an AAUS Scientific Diver. Beyond that, it depends on the needs of your research. I'm not a Marine biologist, but I'm a non diving related Ph.D. candidate who helps with our scientific diving program.

As was said, rebreathers are great for deep or long dives. They simplify logistics for deep or long, at a cost of being more complex than something that gives gas when you inhale, if some is still left in that tank.

Anyone working while breathing compressed gas underwater as a scientist, even at university as graduate or undergraduate students, must be certified as Scientific Divers. Most universities, with a Marine Bio program, have a program to train them, under the umbrella of AAUS for those in the US, American Academy of Underwater Sciences. It is a OSHA regulation thing, History, other countries have similar requirements.

If you want to dive on a research project at school, you need to be a 30' Scientific Diver. Later, you would gain experience and training for 60', 100', ... and whatever mixed gas or rebreather you need for your research. In terms of Marine Bio, do not worry yet about rebreathers. Get solid open circuit dive skills, Buoyancy/Trim/Propulsion(frog, reverse, and helicopter kicks), First aid, rescue, dive master level knowledge of diving physics and physiology. These are all parts of the basic scientific diver program. (And all just tools for your cool work and interest on X.)

Search for 'Scientific Diver' and the web sites of universities near you. If your university does marine bio, they almost certainly have a scientific diver training program. Check how often they give the class! Set up your diving so you are ready for it. The programs are all similar in terms of coverage as they all must meet the same standards.

There may be 'junior' programs near by. I know there is a group in Atlanta that teaches younger students in a 'let's do science' frame work associated with people from Georgia Tech's scientific diving staff.

Few, if any, would expect you to be a scientific diver before university. I would be shocked if any prioritized it in an application over what science you have done, not-yet-observed-on-scuba. It is a tool you will need, but one rare to get before university. Past that, rebreathers are something likely only a few graduate students use, if any. It really just depends on their research, its funding, the trade off of the time to get them trained vs getting interesting results some other way, and the university Diving Officer approving the dive plan using it as a safe procedure for those divers on that research project.

There are others here, @tbone1004, with more experience in scientific diving. I have all the core recreational certifications, but I list 30' scientific diver as my highest.

As a minor secondary recommendation, most of the scientific divers I've seen dive with BP/W, as it is adaptable with lots of places to hook equipment etc to. And scientific diving starts looking a lot like technical diving. You at least need to hold position and orientation over what ever you’re trying to look at, while taking notes and not destroying it or other stuff near by.

Welcome to science, and more diving. There is lots of cool stuff to see and study out there. :)

Edit: I did not quite answer your question. If your research, post grad school, takes you to study below say 200', a rebreather will be very handy, or essential. If it involves spending 10 hours a day at 30', a rebreather may be handy as well, and quieter thus less disruptive of the fish behavior, which might affect your research results. But there is a lot of research outside those two. I'd say if you are very interested in rebreathers, pending parental advice, picking them up in the late stages of undergraduate or in grad school would give you a *few* more options for research. But keep in mind their increased complexity. If you want to study X in remote part of the world Y at 60' as a grad student, the consumables for open circuit, air or Nitrox in a tank, is all over the place for the recreational dive industry. The consumables for rebreathers, O2 gas, dilute gas, CO2 scrubbers, are available but less so.

And the rebreather, or open circuit rig, is really just the way you get to work and part of your field kit while there. It's what you need to get the job done most efficiently. Your skill at being at a position and orientation in the water column needs, ideally..., to be unconscious so you can focus on the science. The diving-as-background-task is a reason why they do this in buddy teams, possibly with extra safety divers.

I disagree that a university student would never use a rebreather, based on conversations with our staff about snorkels for observational studies v.s. a hard 5-15' bottom with pure O2 rebreathers. An experienced careful rebreather young grad student seems safe on an existing 30' project that used rebreather to not disturb behavior, and certainly at 20'.
 
A poorly monitored rebreather will kill you way shallower than OC ever would. A failed OC first stage at 12m? Buddy, then CESA in order of desirability. You will know because it will get way hard to breathe.....

A failed O2 first stage on a rebreather at 12m? Closed, you quietly pass out and die from hypoxia. Failed open? While you're trying to fix or figure out your buoyancy issues arising, you end up on a PPO2 of 2.2 which may or may not ruin your day.

It couldn't happen, blinking red flashing beep zapping all around with the instructor next to you.. you don't even need to know what's about, however being a scuba diver and not knowing what's the ppo2... hem...

They won't let you use a reb for the first time and without a proper course in open water deep dives and without the constant supervision of an instructor. It's actually safer to dive with a reb in this circumstance than diving as an open water with another inexperienced open water at 18m.

Rebs are OK even for a starting scuba diver in a very controlled environment without knowing how it works. Let's be less big daddy, people aren't idiots. :)
 
It couldn't happen, blinking red flashing beep zapping all around with the instructor next to you.. you don't even need to know what's about, however being a scuba diver and not knowing what's the ppo2... hem...

They won't let you use a reb for the first time and without a proper course in open water deep dives and without the constant supervision of an instructor. It's actually safer to dive with a reb in this circumstance than diving as an open water with another inexperienced open water at 18m.

Rebs are OK even for a starting scuba diver in a very controlled environment without knowing how it works. Let's be less big daddy, people aren't idiots. :)

Tell that to the guy in Hawaii who just died in class.
 
Tell that to the guy in Hawaii who just died in class.
Ensign Brian Bugge, 35

Navy officer, 35, dies in off-duty diving mishap

Bugge was pulled, unresponsive, from the water by his instructor during a training dive the morning of May 20
2018
He left behind a wife, 2 year old child and a 3 year old child.

Rebreather deaths happen with shocking regularity. Often, to very experienced and respected members of the dive community.
 
When I switched to CCR diving, I was very conscious that there had been a number of accidents with very experienced divers. The major cause, arrogance and not taking enough time to engrain the new skillset before resuming deep or high task load diving.
I took a year out, doing shallow club dives. I even made one of our skippers do a double take, I dived the Sallcette on my twinset (40-50m) in the morning, and a shallower site in the afternoon on CCR.
Most CCR problems are slow onset issues, unlike OC, which works or it doesn't. If you are monitoring the unit, you have a pretty good idea you have an issue, and time to plan how you are going to resolve it. MOD1 the answer is bailout off loop (OC). Once you progress to MOD2 & 3, its stay on the loop, manage and resolve.
The main concern for me has always been CO2, this is the first season I've actually had a OC/CC mouthpiece fitted, which is really a must (I don't think its feasible to hold your breath long enough to switch to a separate OC regulator if you are suffering with CO2, by that time rational control of breathing rate is overridden by the subconscious.)
Most other issues are manageable on the loop.
 
Rebs are OK even for a starting scuba diver in a very controlled environment without knowing how it works. Let's be less big daddy, people aren't idiots. :)
I'm not saying any single person in this thread is an idiot specifically. However, I disagree. Most people are idiots. Statistically speaking, there must be several idiots posting in this thread.

I guess I should consider the old adage "if you don't know who the idiot in the room is, it's probably you". Ack!
 
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