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.

 

[grantctobin]

I taught the rEvo for a few years, MOD I, II and CCR cave classes and thought the WOB was good. I now teach on the Choptima, same set of courses and the WOB is as good if not better that the rEvo IMO.

Because one can actually breathe a Choptima in flat trim, as opposed to...the other thing.

 

[PfcAJ]

Seems to be a lot of false advertising going on with DIvesoft, they say the liberty is bailout ready in standby mode like OC until switched to CCR or the PPO2 drops to 0.8%. Thanks I’ll do some more research.

Also consider in the case of co2 if you can even manage to switch the loops at all. The drive to breath in a high co2 state can be absolutely overpowering. Holding your breath and having the dexterity to switch and open the BOB loop might just be impossible.

OC (with BOV) if a quick lever turn and you’re back on track to normalcy. Your buddy can even do it for you if you’re impaired.

 

[gordonscuba]

Being able to bail out to open circuit is much simpler and safer than bailing out to another ccr. I think the concept of a "bailout rebreather" was born out of necessity, when people doing extremely advanced exploration got to a point where the sheer number of bottles required by OC bailout made the exploration they wanted to do impossible. Those explorers were making a considered choice to introduce added complexity and risk, and they were willing to accept the considerable personal risk because there simply was no other way to explore further.

 

[steinbil]

Also consider in the case of co2 if you can even manage to switch the loops at all. The drive to breath in a high co2 state can be absolutely overpowering. Holding your breath and having the dexterity to switch and open the BOB loop might just be impossible.

OC (with BOV) if a quick lever turn and you’re back on track to normalcy. Your buddy can even do it for you if you’re impaired.

Is it a viable option to have both? Considering the advantages of having immediately accessible bailout gas, it made me wonder if having a BOB + a smaller quantity of bailout for dealing with issues/switching rebreather would be feasible. Or will that just add too much gear and complexity?

PS
Purely an intellectual exercise, a hypothetical question to tickle my fancy, since I won't be diving a CCR for many years, if ever.

 

[ahereng]

Is it a viable option to have both? Considering the advantages of having immediately accessible bailout gas, it made me wonder if having a BOB + a smaller quantity of bailout for dealing with issues/switching rebreather would be feasible. Or will that just add too much gear and complexity?

PS
Purely an intellectual exercise, a hypothetical question to tickle my fancy, since I won't be diving a CCR for many years, if ever.

The members of our dive-club that uses BoB's also have a deep OC-bailout(mostly with Bov) as a "transitional" BO before going to the BoB. This BO also serves as diluent for the BoB. There are minor differences in how they are using the BoB between the divers.

 

[PfcAJ]

Is it a viable option to have both? Considering the advantages of having immediately accessible bailout gas, it made me wonder if having a BOB + a smaller quantity of bailout for dealing with issues/switching rebreather would be feasible. Or will that just add too much gear and complexity?

PS
Purely an intellectual exercise, a hypothetical question to tickle my fancy, since I won't be diving a CCR for many years, if ever.

I suppose it’s viable and I’m fairly sure people are doing it.

Complexity of procedure makes it seem reasonable only in extreme cases. No one here is doing extreme cases. OC is simpler and absolutely realistic for virtually all diving; Wet Mules and maybe some WKPP/KUR type dives excluded. *maybe*.

 

[rjack321]

Seems to be a lot of false advertising going on with DIvesoft, they say the liberty is bailout ready in standby mode like OC until switched to CCR or the PPO2 drops to 0.8%. Thanks I’ll do some more research.

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

 

[Member002]

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.

Edit: The above is a simple example to just make a basic point comparing two hypothetical divers. You can double or triple all the years involved and the point being made does not change.

 

[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