mCCR 1 Class - Carlsbad, CA March 2010

[Cave Diver]

Maybe you could, I dont really know. I believe the counter-lungs are different (as they are up behind the neck and they are connected differently). There are I think a number of other changes also but I am honestly not that familiar with how the standard unit comes.

As far as I know those are the same CL that were introduced for the standard meg a while back. I gave some consideration to switching to them to reduce chest clutter, but wanted to do some more research first.

I'd like to see a picture of the back of the unit as well, but just at first glance it opens up a few ideas that I might try and implement.

 

[TechBlue]

Just playing devil's advocate at first glance it seems to me that by mixing OC and CCR capabilities to allow for mixed diving teams you are also adding additonal points of failure into the design. I am not knocking the philosophy and I would like to see one but wouldn't it be better not to dive with mixed teams and use CCR based gas planning and bailout procedures?

 

[lamont]

Maybe you could, I dont really know. I believe the counter-lungs are different (as they are up behind the neck and they are connected differently). There are I think a number of other changes also but I am honestly not that familiar with how the standard unit comes.

I think I've heard about those counterlungs as an option to a vanilla Meg... There's also mCCR versions of Megs...

So, most of this doesn't sound that new... It seems to only be different from what you could already get on a Meg by pulling large amounts of dil/bailout on the back and slinging the O2 -- maybe along with the manifold and isolator, but that seems to follow logically from combining the dil/bailout and putting it all on the back...

S-drill donation is also similar to what I've seen mCCR meg divers doing, but they typically route a donatable reg off the slung bailout to the right shoulder clip.

 

[limeyx]

Just playing devil's advocate at first glance it seems to me that by mixing OC and CCR capabilities to allow for mixed diving teams you are also adding additonal points of failure into the design. I am not knocking the philosophy and I would like to see one but wouldn't it be better not to dive with mixed teams and use CCR based gas planning and bailout procedures?

Sure, play the advocate, cant hurt

First off, which points of failure are you talking about ? The only extra one I can come up with is that there is now an isolator that could feasibly fail and you will no longer be able to use the RB or Bailout.

In this case, you simply go to your buddy, and access either their open circuit gas (of which they have enough to get you out), OR you could feasibly (if in a cave or a deep dive) plumb their Backgas into your "dil adder" and go pSCR (just inject dil which for us is always breathable at depth)

You can also for exploration/deep diving add a second isolator.

This RB does play nice with other DIR OC buddies, but it's also awesome with all CCR teams.

Each RC member essentially has two complete systems to get them out of the water (the Rebreather and the OC gas on their back).

So would you make take some time to go over the "standard" CCR bailout and maybe you can list the advantages of it ...I would like to hear the pluses.

 

[limeyx]

I think I've heard about those counterlungs as an option to a vanilla Meg... There's also mCCR versions of Megs...

So, most of this doesn't sound that new... It seems to only be different from what you could already get on a Meg by pulling large amounts of dil/bailout on the back and slinging the O2 -- maybe along with the manifold and isolator, but that seems to follow logically from combining the dil/bailout and putting it all on the back...

S-drill donation is also similar to what I've seen mCCR meg divers doing, but they typically route a donatable reg off the slung bailout to the right shoulder clip.

"New" or not, I think this system is the only CCR I would call "DIR" and for me, that's the important point --- this follows all the principles I and my buddies have used in out diving until now, extending them where necessary.

I know these lungs are different than at least one other lung for the Meg because you can order them with different connection points. However, I have no idea if this is exclusive to UTD or if other customers could just order them. This is about far more than just counterlungs though

It's the combination of the way things are setup/organized, *and* the training and dive planning that makes it (IMO).

 

[lamont]

Just playing devil's advocate at first glance it seems to me that by mixing OC and CCR capabilities to allow for mixed diving teams you are also adding additonal points of failure into the design. I am not knocking the philosophy and I would like to see one but wouldn't it be better not to dive with mixed teams and use CCR based gas planning and bailout procedures?

If you expand the team to include support divers, there's nothing wrong with having 70-foot support on OC, while the main team is on CCR. For practice on dives not fully utilizing the CCR, there's also nothing inherently wrong with mixing CCR and OC if everyone knows what they're doing.

 

[lamont]

"New" or not, I think this system is the only CCR I would call "DIR" and for me, that's the important point --- this follows all the principles I and my buddies have used in out diving until now, extending them where necessary.

I know these lungs are different than at least one other lung for the Meg because you can order them with different connection points. However, I have no idea if this is exclusive to UTD or if other customers could just order them. This is about far more than just counterlungs though

It's the combination of the way things are setup/organized, *and* the training and dive planning that makes it (IMO).

I'm actually not dissing it by saying that a lot of it isn't anything new. That's a plus for me, since it is reusing standard concepts and putting them into a system. And I agree that putting the bailout on the back and focusing on the engineering of the bailout makes a lot more "DIR" sense to me.

Be interesting to see a compare-and-contrast between the DIR-style backplate and one of the standard Meg harnesses as well. That's one of the thing that I've looked at on a Meg and intuitively felt like it could be DIRed-up a little bit more. Looked reasonably solid, but didn't quite have the bulletproof simplicity of a backplate to me (that's entirely a qualitative feeling on my part though). I wonder what Leon would point out that you lose...

 

[limeyx]

I'm actually not dissing it by saying that a lot of it isn't anything new. That's a plus for me, since it is reusing standard concepts and putting them into a system. And I agree that putting the bailout on the back and focusing on the engineering of the bailout makes a lot more "DIR" sense to me.

Be interesting to see a compare-and-contrast between the DIR-style backplate and one of the standard Meg harnesses as well. That's one of the thing that I've looked at on a Meg and intuitively felt like it could be DIRed-up a little bit more. Looked reasonably solid, but didn't quite have the bulletproof simplicity of a backplate to me (that's entirely a qualitative feeling on my part though). I wonder what Leon would point out that you lose...

Yes, it was a big thing for me too --- even though donating is slightly more complex, it's no harder than what a certain other "DIR" agency has deemed "DIR" for their Rebreather

I have never seen a Meg harness honestly, my standard backplate and a slightly wider wing fit just fine, and things like my knife, backup lights etc. are just where I expect them to be.

 

[TechBlue]

Sure, play the advocate, cant hurt

First off, which points of failure are you talking about ? The only extra one I can come up with is that there is now an isolator that could feasibly fail and you will no longer be able to use the RB or Bailout.

In this case, you simply go to your buddy, and access either their open circuit gas (of which they have enough to get you out), OR you could feasibly (if in a cave or a deep dive) plumb their Backgas into your "dil adder" and go pSCR (just inject dil which for us is always breathable at depth)

You can also for exploration/deep diving add a second isolator.

This RB does play nice with other DIR OC buddies, but it's also awesome with all CCR teams.

Each RC member essentially has two complete systems to get them out of the water (the Rebreather and the OC gas on their back).

So would you make take some time to go over the "standard" CCR bailout and maybe you can list the advantages of it ...I would like to hear the pluses.

It's a bit late but in the short form,
Regarding failure points as you say you have the manifold, a couple more regs and hoses.

I dive my KISS mCCR with onboard gas dedicated to the loop, BOV and wing inflation are plumbed into stages. For deeper dives offboard gas is plumbed in through a switching block. OC bailout is calculated on having enough OC between two divers for one of them to bail based on the premise that it is highly unlikely that both breathers will have total failures. (I know a little alpinist for UTD ) All stages are setup with common QC's to allow switching of bottles. Personally I keep all fittings and hoses on the loop to a minimum to reduce points of failure.

From what my take of the UTD philosophy is that you are wearing a breather and each team member is carrying enough gas including slung stages to follow the rule of thirds which to me defeats the object of the breather. The same would apply to support divers on OC that makes sense, but are you now also carrying enough gas to support your support divers? If this is the case then again it would be better for the support divers to be on breathers too.

 

[limeyx]

It's a bit late but in the short form,
Regarding failure points as you say you have the manifold, a couple more regs and hoses.

I dive my KISS mCCR with onboard gas dedicated to the loop, BOV and wing inflation are plumbed into stages. For deeper dives offboard gas is plumbed in through a switching block. OC bailout is calculated on having enough OC between two divers for one of them to bail based on the premise that it is highly unlikely that both breathers will have total failures. (I know a little alpinist for UTD ) All stages are setup with common QC's to allow switching of bottles. Personally I keep all fittings and hoses on the loop to a minimum to reduce points of failure.

From what my take of the UTD philosophy is that you are wearing a breather and each team member is carrying enough gas including slung stages to follow the rule of thirds which to me defeats the object of the breather. The same would apply to support divers on OC that makes sense, but are you now also carrying enough gas to support your support divers? If this is the case then again it would be better for the support divers to be on breathers too.

Rule of 1/3s has nothing really to do with it (could be 1/6ths 1/4ths, "all available")

What we do is the following (and this is the same principle as Open Circuit )

We each carry enough gas to get 2 divers to the next breathable source of gas in the event of a single "major failure"

This is different based on whatever gas rule we plan to use (all available, 1/2's 1/3s 1/6ths etc) So does NOT always have to be 1/3s

This gas is held in the Backgas (same as on open circuit)

The "next breathable" gas may be
- the surface
- deco bottle (either carried or staged in a cave etc)
- stage bottle that we brought into the cave (less likely on CC)
- "Safety" bottle that was staged in the cave and not breathed yet

For Open Circuit, each diver calculates how much gas this is for 2 "stressed" (not pannicked divers)

For closed circuit, its similar but you now have a couple of cases

1) All RB team. We each have 2 complete systems on our back (enough OC gas to bailout and a complete rebreather) so in almost all cases, we are self reliant.
The one case we are not is if we are diving a single-isolator and it fails (so we cannot isolate)

So now our RB buddy has to carry enough OC gas for *one* diver (me) to get out and enough gas for himself on the rebreather to exit (any more than that is more than the single failure we assume).

We can obviously decide to carry even more gas should we choose!

2) for a mixed team, the Open Circuit guys need to reserve enough gas for 2 divers (if my isolator fails, they need to get me and them out of the ocean)

The RB diver again really only needs enough gas for ONE person on Open Circuit because if the Open Circuit guy needs gas, the RB diver can just exit on their rebreather (any more is again more than one failure)

Similarly all deco and stages have QCs on and supplemental O2 or dil can be added if needed.

Wing inflation comes from the doubles. Drysuit can be doubles or argon bottle.

We do not carry enough gas to support support divers (I think there is some confusion on that part) any support team has to be self-sufficient in standard DIR terms.

This method works well for "DIR" divers because
- it's very similar to how we have been diving open circuit
- integrates well with OC and CC teams
- doesn't have any automatic/feedback loops that take away control from the diver
- bailout scales by simply adding bigger doubles, rather than carrying an increasing number of AL80s for bailout when you need more than that

I am kind of failing to see the superiority of the "Standard" CCR methodology ....