Beginner question for rebreathers

[tbone1004]

One more question:

does all this applies to SCR as well?
I guess SCR delete some complexity but adds on the weight as you have carry more gas?

For a say 30min bottom time to 30m on EAN32, pretty standard dive with no deco, using twin 12's/hp100's with a rig weight of ~110lbs/50kg *this is just the tanks+regs since bp/w is going to be the same on both systems.
To do that dive with a Mares Horizon which IIRC is the only currently made CE approved SCR on the market weighs 31lbs/14kg fully kitted up, which is quite a bit lighter than 110/50 but then we need to add our bailout. For that dive I'd be fine doing it with a single AL80 on the left which fully rigged is about 50lbs/22kg. It is a bit lighter than the twinsets, but now you have a rebreather on your back, sidemount/bailout tank on your left, and it's certainly not more streamlined and it is considerably more difficult to walk around in on the surface and the doubles are more streamlined in the water anyway.
Technically Mares is going to say you need a pair of tanks though so a pair of AL40's at minimum which are going to be a bit heavier than a single AL80, and once you start adding decompression bottles in there it is a bit of cluster so it's all not worth it to scale up. The Horizon is great for guys doing shallow water extended duration dives in things like scientific diving applications or doing a lot of macro photography, but to go down that rabbit hole to save weight is certainly not a valid justification.

 

[Sure Squintsalot]

I know very little about rebreathers.

Given the costs, added complexity, and UW attention demands, what kinds, and how much, diving must one do to make CCR "worthwhile"?

...and if there's a specific resource that addresses this, please point me to it.

 

[Dusty123]

I know very little about rebreathers.

Given the costs, added complexity, and UW attention demands, what kinds, and how much, diving must one do to make CCR "worthwhile"?

...and if there's a specific resource that addresses this, please point me to it.

They are definitely more practical for anything involving depths requiring helium and even more so in remote locations. They can buy lots of time in overhead environments that oc can’t match, so I feel they are actually safer in some instances. I also think they are more enjoyable to dive and can cut down on deco or even eliminate in some rec/tech scenarios. There is definitely a spectrum with rebreathers as far as complication goes and you pick your poison. I think a triton or similar with a small set of doubles could be nice and light and very capable. I was in Truk and a lighter built person was diving a triton in sidemount and I was pretty envious looked great in the water and way better to travel with than my revo.

 

[PietroT]

I dive with a JJ and I'm 1.71m x 63kg. I find that the unit, ready for diving, is easier to handle than a D12.

If you just want to try different units (Revo, JJ, Xccr, etc), there is a CCR test event in Bodensee in November.

One single shallow dive is not sufficient to fully understand a rebreather, but you have the feeling of how it is and you can see and compare different units.
Ping me in private if you want details.

 

[Sure Squintsalot]

Thanks.... That sounds like a vote for diving wrecks and caves at below rec diving depths. I can see that. That's clearly the case for the Andrea Doria divers. But you'd have to have a ton of experience beforehand to not get distracted by the scenery and pay attention to your gauges? Some the CCR forums make it sound like watching your gauges is a full time job.

I also see the benefits behind having no bubbles, if you're wanting to get close to wildlife, or attach explosives to a hull. For videography, my UW time is limited by the batteries and beefier batteries that would justify a CCR would require a very expensive upgrade.

Professional salvage divers likely benefit from CCRs, avoiding repeated decompressions to swap out tanks. I can totally see that.

I've seen discussions about using CCR recreationally in 20' of water. What's the point? Can't I just swap out (very inexpensive) air tanks til the cows come home?

Unless I dive with other CCR divers on a liveaboard, wouldn't I have to surface with the other OC divers? So, I'd have to find CCR groups and dive with them; probably a LOT easier if you live near water.

Seems like the barrier to entry into CCR diving is a pretty high bar. Have I missed anything, or misunderstood something?

 

[The Chairman]

Seems like the barrier to entry into CCR diving is a pretty high bar.

It's not for everyone, that's for sure. I would rather dive CCR than anything else, mostly because of the quiet. It's amazing to me how close you can get to fish if you're not blowing bubbles.

 

[Sure Squintsalot]

.....I would rather dive CCR than anything else, mostly because of the quiet.

I'm already hard of hearing, so...

benefit negated !

(but I see your point)

 

[The Chairman]

I'm already hard of hearing, so...

You'd be surprised. I have hearing loss in my right ear and any ambient noise exacerbates that. I can hear the ocean on a rebreather. The shrimp snapping, the velvety cymbal noise of others' bubbles moving through the water, boats approaching, and so on.

 

[Dusty123]

I actually have no gauges on mine lol, but I do have transmitters going to my hud that I look at and might think about a few times during the dive. Yes you have to monitor your ppo2 but generally nothing happens very fast on ccr…generally. Its decents and acents that you are really watching your computers. On the bottom Im site seeing and just keeping an eye on things with my peripheral vision.

 

[Marie13]

Some perspective from a new CCR diver doing recreational depths for the meantime.

I got certified on my CCR last fall. Air diluent, 100ft/30m max, no deco. I’m not OC deco trained (lack of helium to finish OC AN/DP/Helitrox put the stop to finishing that last year). I get marked enough at 130ft/40m that I absolutely need helium. I’m slowly building hours. At about 22 hours now. I’m in the US MIdwest so diving season here is April-October for the most part. I cave dive in the winter, but my instructor told me I need 50 hours before I take my CCR in a cave. I’ll cave dive OC sidemount this winter. Also easier to travel with OC gear than the CCR. I also need 50 hours to do helitrox, so hopefully next year. I don’t feel the need to rush things.

I’m enjoying diving shallow. I don’t feel the need to dive deeper unless there’s a nice wreck to see (Great Lakes diving). I also tend to dive colder water, so the

Another thing that is VERY nice about CCR diving are the gas logistics. I’m not dragging 2 pairs of steel 85s around to get fills. I have to drive an hour each way to get O2 fills (air fills are available close). So I have 4 O2 bottles and 2 pair of steel LP50s (a bit larger than AL40) for BO (I‘ve owned the 50s for a couple of years). The 4 O2 bottles mean I can go at least 3 weeks, maybe 4, without having to get O2 fIlls. I can get by for a good bit on 1 fill for the 50s. I have a Kiss Spirit, so dil is off board (left tank feeds dil and wing, right is BO and drysuit). Yes, the entry cost is high for CCR, but the gas logistics are a nice positive.