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.

 

[Moerae]

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.

I was giving a simplified example to make a basic point. Even with your changes my point still stands 100%.

Sure, give both divers 20 years of realistic experience on both paths and do the comparison.

If your example diver went CCR right away they would have almost twenty years of CCR diving under their belt, instead of just eight. For the OC diver it would have been eight years since they dove OC on the big dive.

I'm not saying everyone should dive into CCR and skip OC tech. I'm just saying that people are just shouting sound bites about bailout without actually considering the holistic picture around the risk/competence of these two divers in comparison.

 

[Whitrzac]

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.

This person would never make it past trimix. Let alone ADV mix. If by some small mirical they do, telling them they cant go below 150ft for the next 2-3 years? When has that ever worked?
Or are you saying they can switch back to OC for their mix dives while doing shallow dives on the RB? So now you have someone jumping in the water with OC gear that hasnt been dove in 6 months.

Its not 1995 anymore, get with the times.

 

[Celt]

Sure the Liberty is "ready" it's the diver that isn't - except in some extremely rare circumstances.

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.

 

[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.

 

[steinbil]

What are the statistics, if any, on cause of fatalities/accidents on CCR? Do the accidents mostly happen on the loop or after bailing out? Is reluctance to bail out a significant cause of incidents? Would lives be saved if CCR divers bailed out earlier? If they had better OC skills after bailing out?

Considering the law of primacy, shouldn't the skills most vital to survival be taught first (and practiced most)? Will practicing bailouts regularly give you the same effortless control over buoyancy on OC while task loaded as someone who's done Tech OC diving for many years? Is rebreather diving complex enough that you should be very comfortable with all other aspects of being underwater before you learn to use one? Is diving a CCR in shallow water really a low-risk way of gaining comfort and experience underwater - isn't there a lot of CCR accidents in shallow water?

Are the risks of CCR diving on the loop mostly related to motor skills? Or a lack of problem solving skills? Or are they procedural? Are they caused by task loading? Panic? Complacency? Exceeding limits of competence?

Different risks are mitigated by different means:
- complacency and procedural errors are mitigated by safety culture and checklists
- motor skill issues are mitigated by perfect practice (learn it right early, practice often in a way that ensures few mistakes in practice)
- problem solving skill issues are mitigated by knowledge, experience and problem solving practice (failure training)
- task loading issues are mitigated by progressive exposure and appropriate complexity/difficulty

Nobody should take my advice on CCR, but I have a few random thoughts:
- Learning to do tech dives OC safely is easier/less complex than learning to do tech dives on CCR safely
- Most skills learned on OC are valuable for a CCR diver: comfort in the water, OC buoyancy, problem solving skills, mentality, team skills, importance of procedures, knowledge of the environment+++
- When learning complex skills, it's often useful to break down into smaller pieces and build complexity slowly
- When you need OC skills on CCR, you're already in trouble, wouldn't it be nice to fall back on your strongest skill set?

 

[Germie]

And what I find important and why I sometimes hate my ccr is that when I am doing dives on ccr that can also easy be done on OC, my oc friends already are relaxing and having a beer and I am cleaning that #$@#$@#$^machine and preparing it for the next day.

So if you want to only dive a ccr, and you have oc diving friends, your unit will need extra care. And don't take shortcuts with this. It can bring you in trouble.

Also a thing that I had a few weeks ago for the first time is that I prepared my unit completely for a cave dive. Put it in the car and only 30 minutes later I had to turn it on. And 1 cell was completely dead. That means you have to break it down again, replace a cell, and I can tell you that it's annoying as others are waiting for you. It does not happen often happely, and in this case it was completely unexpected as it was only november and the cells were produced in may this year. But what I want to tell with this, is that even if you check everything, a ccr can have problems more easy.

So if you want to go for CCR, it is possible, but you must be a person that can work strict, maybe more strict than diving oc. It is more than checking your gases and checking for leaks.

And also a thing to consider is that a ccr is more expensive when you dive shallow. If you stay within the air/nitrox limit, you will never earn a unit back. And if you are not that experienced, you need to dive the unit on shallow dives also. And even if you don't dive a lot, cells are 300 bucks for 3 and last a year if they don't break before. So it is not only hold the cylinders in test, also service the first stages (and oxygen clean), hold the cells up to date, etc. Sorb is quite expensive and oxygen is harder to get in my country than air.
But yes, I have 1 special picture taken at only 2m depth and I am for sure it was undoable on oc because of the bubbles. So that is why I love my ccr.
But I must say, on the easy sundaymorningdives, I take a twinset and make it easy. Then I can go in summer the whole day to friends and don't worry about an expensive ccr unit in my car that has growing bacteria in it due to the sun.

 

[Celt]

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.

Training agencies and clients make their own decisions.

 

[rjack321]

This person would never make it past trimix. Let alone ADV mix. If by some small mirical they do, telling them they cant go below 150ft for the next 2-3 years? When has that ever worked?
Or are you saying they can switch back to OC for their mix dives while doing shallow dives on the RB? So now you have someone jumping in the water with OC gear that hasnt been dove in 6 months.

Its not 1995 anymore, get with the times.

Shrugs are you diving to see new and special stuff or just going for more scraps of expensive (and rarely that valuable) plastic validation.

TONS of people take AN/DP, hyperoxic, or normoxic trimix and never feel a need to dive beyond those gas 100-200ft ish boundaries or invest in a CCR either. The implication that you haven't "arrived" as a diver until you're doing 100m+ on CCR is just a dumb quirk of the internet.

 

[Moerae]

I'm not arguing for early CCR. I think, for example, there are a lot of excellent points about OC tech being simpler and allowing people to learn the fundamentals of tech diving in a bit more forgiving setup. I think there is also a lot of "human factors" value to a team really deeply understanding how fast gas goes at depth when they do their bailout planning.

I'm just looking for a little nuance to be added, here, and some acknowledgement that there are tradeoffs involved and not just a cut and dry "x is obviously better and y has no benefits".


I'm still wondering what strong "wait before CCR" proponents think about our two hypothetical comparison divers.

Diver A: 20 years CCR experience (starting with air dil no deco, ending with mod3)
Diver B: 12 years OC tech experience (AN/DP->adv mix), 8 years CCR experience (mod1->mod3).

I think ignoring this comparison does a disservice to the conversation. Are people really arguing that Diver A isn't going to be extremely competent? Possibly even more competent than Diver B for the vast majority of situations and problems? Can we agree that both divers will need to practice bailout regularly to ensure they are capable and ready to do so in an emergency? Are people really going to think that diver A never dives open circuit or fine tunes OC buoyancy sufficient to be competent during a bailout?

 

[gordonscuba]

Diver A: 20 years CCR experience (starting with air dil no deco, ending with mod3)
Diver B: 12 years OC tech experience (AN/DP->adv mix), 8 years CCR experience (mod1->mod3).

Both divers could be extremely good.

Any chance someone starting now follows the path to become Diver B? In other words, who exactly is planning to spend 12 years doing big OC tec dives requiring large volumes of Trimix, given the cost of He and the status of He as a non-renewable resource?