Question CCR for recreational depths

[CT-Rich]

So this is a curiosity question. I had the chance to use a R1 O2 rebreather the other day in a try it dive at local pool. It was a pretty cool experience and it prompted a question. Would one of these rebreathers be able to replace my conventional OC scuba for diving at recreational depths?

Here is my situation. I typically dive with a steel 120 and most if not all my diving is above 100'. I am getting older and father time is catching up with my back. at some point I will no longer be able to sling all the lead and steel. The CCR is much lighter than a traditional OC system.

I understand that because of the PPO of a pure O2 diving is limited to 20' and repeated prolonged O2 can have an effect on your lungs. But I heard from the guy doing the try it dive that the rigs can be modified to use air as a diliuant and work at greater depths.

My question is would this be a viable option? With a upgraded DR1 would it be a viable way to dive within recreational limits? With a system like this would it a kin to breathing Nitrox at a fixed ratio or would it would the gas blend be adjustable like used in other CCRs? This is mostly an academic exercise, but I would not mind being able to go out on my usual underwater bumbles, which normally range from 30-60 FSW without having tank pressure as my limiting factor.

 

[tbone1004]

I assume you mean the RD1?

The RD1 as it comes is an oxygen rebreather, single gas where oxygen sensors are not necessary and can often be made with just an automatic addition valve. 30ft is the military depth limit, but generally 20-30ft max depth.
It appears they have a control system upgrade, but basically adding sensors and manual addition valves will allow it to be converted easily to an mCCR.
The conundrum with all closed circuit rebreathers in recreational depths is that they are at their highest risk when shallow. This is particularly true of mCCR's that are not able to actively maintain a ppO2 setpoint.

SCR units are akin to breathing nitrox at a fixed ratio but I believe the Mares Horizon is the only commercially available SCR on the market.

 

[Heat Miser]

I had the chance to use a R1 O2 rebreather the other day in a try it dive at local pool. It was a pretty cool experience and it prompted a question.

What certification agency can train you on the RD1?
*Subsequent Edit "What shut down drills do you do on that training, looks difficult?"

I had a look on their page and it looks like there are further mods for taking it deeper limits than 6 m on O2 .... ie the SCR/CCR mods ...

I dive alot of my CCR to recreational depths, but they are both eCCR ... as per above post

 

[211ratsbud]

I'm pretty sure Mr Lombardi is on here. Someone tag him? He's a literal encyclopedia of knowledge and experience.

 

[OTF]

So this is a curiosity question. I had the chance to use a R1 O2 rebreather the other day in a try it dive at local pool. It was a pretty cool experience and it prompted a question. Would one of these rebreathers be able to replace my conventional OC scuba for diving at recreational depths?

Here is my situation. I typically dive with a steel 120 and most if not all my diving is above 100'. I am getting older and father time is catching up with my back. at some point I will no longer be able to sling all the lead and steel. The CCR is much lighter than a traditional OC system.

I understand that because of the PPO of a pure O2 diving is limited to 20' and repeated prolonged O2 can have an effect on your lungs. But I heard from the guy doing the try it dive that the rigs can be modified to use air as a diliuant and work at greater depths.

My question is would this be a viable option? With a upgraded DR1 would it be a viable way to dive within recreational limits? With a system like this would it a kin to breathing Nitrox at a fixed ratio or would it would the gas blend be adjustable like used in other CCRs? This is mostly an academic exercise, but I would not mind being able to go out on my usual underwater bumbles, which normally range from 30-60 FSW without having tank pressure as my limiting factor.

There may be something to pure O2 CCRs for shallow dives, I don't have that specific experience but have entertained the fantasy of getting one. I think there are people here who dive them. If your "thing" is shallow water multi-hour macro photography dives I could definitely see the appeal of a pure O2 machine. But you would be truly limited to 20 feet.

As for going to full blown eCCR/mCCR in your situation - I wouldn't recommend it to you. CCRs are full of hidden costs and complexity. The ratio of expense and fussing to enjoyable dive time gets horribly worse compared to a single steel tank. CCRs are absolutely worth it for deep dives or serious overhead environments because of their extreme endurance and helium efficency. If you're not worried about needing extra hours to solve a problem or do long decos, or find yourself spending thousands per year on OC helium fills then you probably won't be overjoyed with a rebreather. That said I do dive mine shallow for fun, but only because I already have it and its good to keep in practice.

If you're looking for a configuration change for lighter weight or more bottom time - maybe small doubles or sidemount?

 

[AJ]

Here is my situation. I typically dive with a steel 120 and most if not all my diving is above 100'. I am getting older and father time is catching up with my back. at some point I will no longer be able to sling all the lead and steel. The CCR is much lighter than a traditional OC system.

As I understand the real problem is the weight on your back? You should ask yourself if a CCR is the right tool for the job. A CCR is a complex way of diving which has benefits, even shallow, but also drawbacks. What I would suggest is to assess what you really want and need. Maybe sidemount diving with two smaller tanks is a viable yet simpler option to releive stress on your back?

I dive backmount, sidemount and JJ-CCR. They all have their benefits, but also their drawbacks and risks. I adapt my tooling according to the situation. Boat = backmount, difficult entry = sidemount, deep (> 30 to 40 meters) = CCR.

 

[Heat Miser]

I dive backmount, sidemount and JJ-CCR. They all have their benefits, but also their drawbacks and risks. I adapt my tooling according to the situation. Boat = backmount, difficult entry = sidemount, deep (> 30 to 40 meters) = CCR.

I think the great thing about the Choptima is that you can adapt it to the situation i.e. boat - single tank backmount, difficult entry - sidemount, deep - rack mounted doubles.

So it depends on the CCR and what you want to do with it.

 

[happy-diver]

I typically dive with a steel 120

Yeah me also but with our size and the huge amount of neoprene we have to sink

So this stuff I built, in the laundry
The front bit dosed up with sorb and a 2l steel bottle with x amount O2 comes in at 17kg-37.47lbs
The back bit, harness amazon wing and nice weight pack is cutsie pie lovely, at only 13kg-28.66lbs
and that's to sink only a 3mm suit

So a 120 pumped to the max 24kg-57.32lbs ish plus weight

But boy these people that talk about all the effort preparing and maintaining, big deal
Prep it a week before and dive it a week after, and have a magnificent time doing it all

 

[AJ]

I think the great thing about the Choptima is that you can adapt it to the situation i.e. boat - single tank backmount, difficult entry - sidemount, deep - rack mounted doubles.

So it depends on the CCR and what you want to do with it.

Choptima and Triton are interesting options for sure. Specially for flying vacations.

Buddy of mine dives Triton with Xdeep sidemount. It's a complex rigging however which takes quite some time to get used to. JJ-CCR rigging is cleaner and more monolithic which I like for boat diving.

 

[MidOH]

Ya'll need to assume that cost and complexity aren't issues thatll stop anyone. 3 sensors every year, aint going to break my bank. Helium use in a doubles rig, might put a damper on things though. The needle valve mccr's arent so complex anyways.

Cost/minute diving might be fair. Costs me a fortune to get in the water. A 2 hour dive, or a 3 hour dive, instead of two 1 hour dives could be worthwhile. Or floating next to the boat while everyone switches their double tanks on it. One rebreather, might noy be much lighter than doubles, but its lighter than 2 sets of doubles by very much. Less weight to carry, less trips up the ladder, and best of all, less swinging a doubles rig onto my back. That might be significant.

Or a weekend camping at a quarry. The breather might only need one swap of sorb For the entire weekend. Rebreather might be more costly, but dicking around with 6+ hp100's isnt a ton of fun either. Especially with incompetent hydro shops and ding dongs running the fill station. Besides, if you want to go back to a singles tank rig for a few dives, you still can.

Solo shore diving could be epic. Or any dive buddied up with another rebreather diver. Or simply to never being the guy to run out of air first, ever again.

An AL30 of dilout, is all I need for redundancy in a quarry. So just the rebreather itself might be fine, quite often. And one slung AL40 would be enough of a bailout for nearly all of my planned Greatlakes wreck dives. An AL80 for sure.

Then there's the "100 dives before you can get the training you need" bit. So youre rec diving anyways.

If cold water works out ok for me, a rebreather will most likely be my next step after that. We're already seeing rebreather guys staging a deco bottle/bailout at the bottom of the quarry, and getting their entires days diving in just one splash.

I might be wrong about all off this. Just trying to figure it out before I get there. There's definately plenty of rebreather divers out there, for a reason. From an outsiders prospective, they seem to offer much that interests me. Downside, is theyre as streamlined as a parachute. But Ive avoided sites with current, pretty well so far.

I think Id rather have the Fathom than a Choptima. Choptima puts all the steel on my back, and floaty stuff on my chest. I think Id rather have it the other way around. Floaty rebreather on my back, tanks slung (if needed).