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

[kensuf]

Part 2..


My takeaways –
1) On a rebreather, calculate how much gas you need for bailout or for reserve, and at the minimum, double it. On OC, it is simply not enough to just apply the rule of thirds, particularly in a complex system or when doing exploration. Thirds is an overly simple rule, and will not save you in low flow or if a secondary problem strikes. When I hear teams planning “team bailout” where between the team members they barely have enough gas to get one person out, or when I hear divers planning thirds in no-flow caves like Peacock and Mexico I cringe – on this dive I had enough theoretically to get 4 divers out, yet needed all of it. Remember, when an emergency strikes, you will need way more gas because of your panicked state of mind and because of the added time needed to deal with the emergency than you usually do. Plan accordingly. Rules like thirds are a starting point and an insufficient, bare minimum. They are not the final answer. I would really appreciate it if instructors taught this, and got their students to always turn below thirds in all but caves with howling flow and huge passages – and particularly that they enforce such an approach in places like Peacock.


2) Once you’ve planned properly, when a situation occurs that gets your attention, keep reminding yourself of what an outrageous amount of gas you have on you, and use that time to move as rationally and slowly as you can. Don’t stop doing your normal checks and protocols because of your desperation to get out of the cave. This really is an example of slow and careful being ultimately safer and probably even faster than a flat-out dash to the exit.


3) At every transitional point when moving from one gas source to another, use that time to ask yourself – just how much gas do I have in each tank? Are the tanks truly opened, and am I sure that they haven’t rolled off? Do I have an alternate to go to if my current reg stops working for any reason? Where exactly is that regulator? Are the others stowed so I don’t accidentally pick up a non-functioning reg when I need one? Be methodical and organized at all times. The same applies to any jumps or T’s. When your rationality is compromised, it is even more important than usual to make sure that your navigation is going correctly. Pick up your spools, markers and arrows, and as you’re doing so, run a mental check that the information that these devices are giving you ensures that you are still swimming to the exit.


I’m not proud of this dive, or of how close I came to a less auspicious outcome. But I’m willing to air my appalling performance in public in the hopes that each of you will reconsider just how well you will perform in an emergency, and how well you’ve planned for that emergency. Keep thinking, slow down, and allow yourself huge reserves of gas. This is particularly important on bigger dives, but equally important on even the shortest one. I hope that sharing this experience will change someone’s behavior enough to allow them to survive a dive that would otherwise have killed them.

 

[silent running]

Thanks everyone for the in depth information - lots to process here.

Another question - is there much point in doing the PADI Rebreather or Advanced Rebreather class before owning a rebreather, since the training is unit specific? (or any other agency, I know it's more about the instructor than the agency)

To the OP, I don’t know how good PADI’s CCR course is, but when I looked at their course materials in the past, I was not impressed. I have always thought PADI was more like a glee club than a training agency. I got certified on my Prism 1 by NAUI with Jeff Bozanic’s Mastering Rebreathers as the text book. This book is well worth reading regardless of which agency you go with. Training agency stocks go up and down, I am not sure what the conventional wisdom is on who is still doing a good job and financially healthy enough to be here 5 years from now. So do a quick search of the net and RB forums for agency references.

And for the record, no training agency will allow you to take an advanced RB course before the air diluent module 1 course. This is as it should be.

I’m one of the few people on here who is a nature lover first and foremost, not a wreck or cave diver, though I do like that type of driving as well. There are several rebreathers which are travel friendly, but there are many choices to be made beyond that. One definite thing I would like to point out about traveling with a CCR is whether or not the most fragile parts, meaning the head and electronics, can fit in your carry-on. I would absolutely never pack those items in checked baggage, and some are easier to dismantle in order to facilitate carrying the most expensive and fragile parts in carry-on. The other important thing to mention about traveling and CCR diving is that if you buy a unit which uses a cartridge scrubber, like an extendaire, you would be required to find destinations which can supply them, or you would have to bring your own and they would take up a lot of space in your luggage and limit your trip duration. Most CCR friendly resorts will have Sofnolime or something similar. I have brought my own sorb, back when checked baggage allowances were bigger for international flights. I once brought two kegs in my checked baggage and was able to dive for an entire month in PNG.

Another concern for the traveling CCR driver is how easy your unit is to service/fix in the field. In this regard, the simpler the design the easier it will be to fix. A needle valve MCCR, like the Pelagian or Fathom, might be the best bet because they don’t have any solenoid O2 addition and simpler electronics than the full electronically controlled units. Another benefit of needle valve MCCRs for photographers is that your buoyancy will be easier to maintain through the frequent depth changes often experienced while trying to chase down a subject. Because, you will not have a computer constantly trying to maintain a tight set point and adding O2 if you ascend 5 feet to get a different angle of the subject. A needle valve MCCR’s rate of O2 flow can be adjusted on the fly and trickles in at whatever rate your need. The downside is you’re not going to be able to maintain a tight set point as easily as you would on an electronic unit, but this matters much less interns of deco obligation than you might think, and you probably won’t be doing a lot of dives with serious deco obligations anyway.

Try dives are a good idea to find out how each unit performs and to get a quick hands on orientation to how CCRs actually work. My own personal opinion is that over the shoulder counter lung designs are the best choice if you anticipate having to hold yourself in different orientations/positions underwater, as most photographers do. OTS CLs breathe best in all positions, whereas other designs tend to be optimized for one best work of breathing swim position...

 

[Valyngar]

And for the record, no training agency will allow you to take an advanced RB course before the air diluent module 1 course. This is as it should be.

Tdi let's start with helitrox ccr course. So you can use 20 helium diluent. That's why you bought the reberether, to use helium, right.

 

[rddvet]

Thanks Ken. I had actually read that in the journal. Didn't realize it was the same story

 

[Dusty123]

To the original poster....Im sure you have read how much a revo sucks compared to all the other ccr. It breathes bad, perfect trim looks like a sea horse, you cant fix the plastic bags in your garage. Want I havent heard is they would rather dive open circuit, didnt have any fun, missed a hot date building it, or missed a dive because of it. Ive learned to except any breathing problems and avoid, I always enjoy it, I show up early, and its simple enough there isnt any issues. I would like to try a jj but I just dont have any need to at this point.

 

[silent running]

Tdi let's start with helitrox ccr course. So you can use 20 helium diluent. That's why you bought the reberether, to use helium, right.

Interesting, an entry level He CCR course, I learned something new. Sounds like a lot of TDI prerequisite courses though, would be interesting to know how much more $ it costs over other agencies mod 1 air dil certifications and their prerequisites.

And no I did not buy my CCR to use helium, though I did later get a trimix certification. I bought my CCR primarily to have better wildlife interactions and for future ambitions. And if the OP is doing his photography at recreational depths, air dil is certainly easier and cheaper until he needs to go deeper and has planned decompression...

 

[Doby45]

Interesting, an entry level He CCR course, I learned something new. Sounds like a lot of TDI prerequisite courses though, would be interesting to know how much more $ it costs over other agencies mod 1 air dil certifications and their prerequisites.

And no I did not buy my CCR to use helium, though I did later get a trimix certification. I bought my CCR primarily to have better wildlife interactions and for future ambitions. And if the OP is doing his photography at recreational depths, air dil is certainly easier and cheaper until he needs to go deeper and has planned decompression...

IANTD also has ART MOD1. Which of course allows you the use of helium. I have never ran anything other than Tri-mix dil through my Fathom. 18/45 for the win, for now. LOL

 

[Valyngar]

Interesting, an entry level He CCR course, I learned something new. Sounds like a lot of TDI prerequisite courses though, would be interesting to know how much more $ it costs over other agencies mod 1 air dil certifications and their prerequisites.

And no I did not buy my CCR to use helium, though I did later get a trimix certification. I bought my CCR primarily to have better wildlife interactions and for future ambitions. And if the OP is doing his photography at recreational depths, air dil is certainly easier and cheaper until he needs to go deeper and has planned decompression...

Costed me 1000 euros in croatia with Jj ccr rentals included. 8 dives, 6 days.

 

[silent running]

IANTD also has ART MOD1. Which of course allows you the use of helium. I have never ran anything other than Tri-mix dil through my Fathom. 18/45 for the win, for now. LOL

My how things have changed since my certification in 2002...

 

[James Ocean]

To the OP, I don’t know how good PADI’s CCR course is, but when I looked at their course materials in the past, I was not impressed. I have always thought PADI was more like a glee club than a training agency. I got certified on my Prism 1 by NAUI with Jeff Bozanic’s Mastering Rebreathers as the text book. This book is well worth reading regardless of which agency you go with. Training agency stocks go up and down, I am not sure what the conventional wisdom is on who is still doing a good job and financially healthy enough to be here 5 years from now. So do a quick search of the net and RB forums for agency references.

And for the record, no training agency will allow you to take an advanced RB course before the air diluent module 1 course. This is as it should be.

I’m one of the few people on here who is a nature lover first and foremost, not a wreck or cave diver, though I do like that type of driving as well. There are several rebreathers which are travel friendly, but there are many choices to be made beyond that. One definite thing I would like to point out about traveling with a CCR is whether or not the most fragile parts, meaning the head and electronics, can fit in your carry-on. I would absolutely never pack those items in checked baggage, and some are easier to dismantle in order to facilitate carrying the most expensive and fragile parts in carry-on. The other important thing to mention about traveling and CCR diving is that if you buy a unit which uses a cartridge scrubber, like an extendaire, you would be required to find destinations which can supply them, or you would have to bring your own and they would take up a lot of space in your luggage and limit your trip duration. Most CCR friendly resorts will have Sofnolime or something similar. I have brought my own sorb, back when checked baggage allowances were bigger for international flights. I once brought two kegs in my checked baggage and was able to dive for an entire month in PNG.

Another concern for the traveling CCR driver is how easy your unit is to service/fix in the field. In this regard, the simpler the design the easier it will be to fix. A needle valve MCCR, like the Pelagian or Fathom, might be the best bet because they don’t have any solenoid O2 addition and simpler electronics than the full electronically controlled units. Another benefit of needle valve MCCRs for photographers is that your buoyancy will be easier to maintain through the frequent depth changes often experienced while trying to chase down a subject. Because, you will not have a computer constantly trying to maintain a tight set point and adding O2 if you ascend 5 feet to get a different angle of the subject. A needle valve MCCR’s rate of O2 flow can be adjusted on the fly and trickles in at whatever rate your need. The downside is your not going to be able to maintain a tight set point as easily as you would on an electronic unit, but this matters much less interns of deco obligation than you might think, and you probably won’t be doing a lot of dives with serious deco obligations anyway.

Try dives are a good idea to find out how each unit performs and to get a quick hands on orientation to how CCRs actually work. My own personal opinion is that over the shoulder counter lung designs are the best choice if you anticipate having to hold yourself in different orientations/positions underwater, as most photographers do. OTS CLs breathe best in all positions, whereas other designs tend to be optimized for one best work of breathing swim position...

Thanks Silent Running - this is great info...