Skipping open circuit and going straight to CCR

[takez0]

This is my first post here. I've learned a ton on this board and I'm grateful for the insights you all provide.

I'm getting into technical diving and I'd like to jump straight into a CCR. Does the group see any benefit or hindrance in skipping open circuit tech training costs and equipment costs and going straight into a CCR? CCR's are obviously an investment. I'd rather not spend money on a new BCD, manifold, tanks, etc., that would only be used specifically for dual-tank open circuit, considering I know where I want to end up already. Let me know your thoughts or if you think this is missed training opportunity.

 

[rjack321]

I have no experience on a rebreather, I was asking, why would someone bother with OC, if they intended to only use a rebreather. Maybe you can explain why someone couldn’t use a rebreather to NDL for training and experience and then use a similar rebreather for bailout. Isn’t the liberty rebreather designed for that. It wasn’t long ago people said rebreathers are only for long and deep dives but today people are using them for all their diving. Things move on.

Among many other reasons...
1) because the 2nd loop may not be breathable
2) the 2nd loop can easily flood under water pressure
3) the 2nd loop may not be solve your CO2 hit at all

Diving a BOB is not just something you casually do on any old dive

 

[gordonscuba]

One unit allows OW to be taught on a rebreather. Personally I think that's to much for a new diver.

There is a common class of misconceptions among non-CCR divers. I hear different variations on this theme, but roughly it's the belief that a rebreather is a nice self-contained little unit that is just a better version of, and a replacement for, any use of a scuba bottle. Like a super-tank that will eventually replace a tank once people get used to the idea.

Of course, true rebreather divers recognize this as a fallacy. The unit I use, like most of the type T CCR units on the market, involves three scuba bottles, three regulators, two computers, two counterlungs, a scrubber which can kill you if improperly packed, mushroom valves that can kill you if improperly installed, 100% oxygen in one of the tanks and certain components which have to be kept oxygen clean, others which need to be sterilized. You still have to know all of the recovery and safety procedures you learn in OW, plus lots more rebreather-specific bailout conditions. Frequent checking and interpretation of the readings from three independent oxygen sensors. Most of the instructors I know are not huge fans of more automated units which still have to somehow solve all of these issues without assuming very much capability on the part of the user.

A local skydiving outfit doesn't allow skydivers to take a GoPro on their first 100 jumps, because they tend to worry more about their photographs and make a mistake. Rebreathers are like that, but much much more.

 

[rjack321]

Ummm assuming your "big dive" is at the hypoxic CCR mix level so 100m plus and hours of deco...

This would be more like it:
Diver A: AN/DP -> 2 years Diving -> Trimix -> 3-4 years diving -> Adv trimix -> 3-4 years diving -> CCR M1 -> 1-2 years diving -> CCR M2 -> 3 more years -> CCRM3 -> 3+ years of diving -> "Big Dive"
Your scenario takes someone from no deco at all to hypoxic CCR dives only 5 years
Mine takes 15-20 years

Seriously are you completely tapped out and done all you can at the trimix level after only 1 year? Yeah no. Stop leaping from card to card with a bare minimum of experience to build on. Get the next level once you've exhausted the options/dives at your current level and are bored.

People get seriously bent and/or die on "big dives" more than you realize. Make sure it's something you *really* want and your kin aren't dependent on you and are ok with your decisions.

 

[lermontov]

I feel like this topic is more complex than a lot of people realize. It seems like it falls into the same category of mistaken thinking as "work as imagined vs work as done"

Lets imagine two divers over six years:
Lets assume they are diving regularly at their highest level of training.
(YOD= Year of diving)
Diver A: AN/DP -> YOD -> Trimix -> YOD -> Adv trimix ->YOD -> CCR M1 -> YOD -> CCR M2 -> YOD -> CCRM3 -> YOD -> "Big Dive"
Diver B: CCR Air Dil no deco-> YOD -> CCR Air Dil deco -> YOD -> CCR M2 -> 2xYOD -> CCRM3 -> 2x YOD ->"Big Dive" -> "Big Dive"

At the end of those six years, on a particular "big dive":
Who is the safer CCR diver?
Who is safer during bailout?

Some observations about the two divers on the day of the "Big Dive"
Diver B has a very conservative first few years on CCR
Diver B has years more experience on CCR than diver A
Diver A hasn't dove OC tech in three years

IMO: Assessing risk is more complex than people are making it out to be.
I'd argue that the diver with three years more CCR experience arguably has less overall risk then the diver that will be more proficient on a bailout. The more years pass the further that diver gets from their few years of OC experience. IMO if anything this highlights to me the importance of regularly practicing full bailouts for either hypothetical diver as being the primary risk reduction related to bailing out.

there are way to many variables on this post to come to any sort of conclusive thought- some people are just better at sports than others

 

[PfcAJ]

Any diver with open water experience to NDL that’s comfortable carrying a side mounted cylinder can switch to CCR. With training and experience they can advance at their own pace if they wish or simply stay at no deco limits.

People can do all sorts of things.

If those things are wise and a good idea is a bit more difficult to parse out.

What you’re describing is neither.

 

[PfcAJ]

It's much less than that.

10m/33ft is 2ATA. At 100% that's a PPO2 of 2.0; way above the amount you should be breathing.

The NOAA level for PPO2 of 1.6, i.e. 6m/20ft, is 45mins for a single exposure and 150mins/2h30 total in 24h.

Is it though?

 

[happy-diver]

If it's an oxygen rebreather, no need for cells, computers, monitoring, even diluent isn't required so when the loop volume drops, you just inject oxygen.

The 6m/20ft limitation makes it utterly pointless. Except maybe as a decompression rebreather?!?

Pretty simple dude rather than just speaking you could open the link and immediately
there are the anwers


"The 'Rebreather Day 1' (RD1) 'kit' provides open-architecture components to allow a very easy build-out for those already RB-savvy.

Our recommendation is to first configure the unit as a simple oxygen only system which is depth limited to 20 feet/6 meters depth. Once proficiency is attained, the open architecture allows for easy customization to SCR, CCR, and other integrated systems."


It's called learning in order for you to be informed so you can come on here and impart knowledge instead of being utterly pointless

So as you have suggested, rather than being the one that for whatever reason comes on here and
always says that rebreathers is hard

Give people their due, where they may be able to learn and take to it more competently than you

(I'm definitely very average!)

On O2 you can learn your unit intimately add some dill when ready makes for a more rounded diver

Diving on O2 in 6m ish is a wonderous experience unto itself



There is more than one diver as there is more diving than one diver does

 

[jale]

Restricting your depth to 6m/20ft seems to be extremely limiting. That's less than the tidal range round here. There can't be many dive sites less than 6m around the world, not in comparison with all the Open Water depth (18m/60ft) sites.

Of course there's not much to a rebreather outside of the plumbing.
But there's a lot more to diving on a rebreather when you must monitor your oxygen levels.

Learning RB with a pure oxy rb is, in my view, the best approach as you get a really good understanding of the loss of oxygen due to metabolism and get familiar with the buoyancy making you aware of the small changes in gas addition or removal. Diving oxy rb teaches you how to adjust CL volume so you can even dive without any bcd-wing.
And in many places, there is a lot to see in the 6m range.
I do regularly dive a pure oxy and I really enjoy the simplicity.

 

[grantctobin]

Do you know any local CCR divers that are willing to facilitate, encourage and nurture your knowledge and inexperience once you’re certified MOD 1 ? Do you have the mental and physical discipline to see the training process through? Are you meticulous to the extreme when it comes to maintenance? Can you afford the upkeep? I’ve met so many divers whose interest ebbs after a few seasons of technical diving. And that’s after they have spent the equivalent of a new car on equipment, training and logistics. If I were in your position today, I would skip the path to OC technical training and go straight to CCR. Provided you have selected the right CCR. That’s the catch 22. There is no learning curve. A myth perpetuated by technical instructors worldwide who dread and loathe nonconformists like you and I. Some of us are born to lead, some of us a born to hide.

Alaskan scuba dude reborn?