Curiousity: CCR and Intro to Cave

[RN]

Because it does happen -

Have them contact me, or you can, and I will give a full account for two incidents (that required 2 bailouts) that may change their mind. One was in OW and the other in a cave.

[flyguy199]

I believe it's NAUI.




Excellent advice! I didn't even think about mentioning that since I always sidemount and have two separate sources as a default.

I don't believe NAUI standards allow CCR use during their cave courses. NAUI requires both the instructor and student to be in an NTEC configuration. BTW, NAUI Cave 1 is their "entry level" cave class. They also have Cave 2 and 3.

[Art Greenberg]

I don't believe NAUI standards allow CCR use during their cave courses. NAUI requires both the instructor and student to be in an NTEC configuration. BTW, NAUI Cave 1 is their "entry level" cave class. They also have Cave 2 and 3.

NAUI does allow CCR in cave classes. I have a NAUI Cave 1 card that is imprinted "CCR Trained".

--
Art

[Bobby]

**snip**

Perhaps if solo diving on CCR, I might consider splitting my bailout into two sources

Hi Rob,

I guess I would still ask the same question: "Is it really necessary to plan for double gas failures?" We don't typically do this with OC. Why would you consider it necessary for CCR?

Warm regards,
Randy

Randy,
Seriously looking for discussion here, not stirring the pot or anything. I'm having a difficult time following your logic. With OC solo diving most recommend carrying a BO cylinder as extra redundancy. When diving in a team OC most consider their teammates gas reserve as a back up to their reserves. Personally I won't go any farther with a teammate on OC or CCR than I will solo with the same gas set up. In fact the majority of teammates I will not go as far as I will solo. It is not a lack of trust, it is not knowing their RMV well enough, in all situations to include high stress to be sure of the gas reserves.

CCR is the same with my view point. I carry the same gases the same way I do solo when diving with a teammate. Also having a cylinder that is dedicated to donating while maintaining a cylinder that is for me to BO allows for someone outside my team needing assistance while not jeopardizing my own BO ability.

I solo dive as much if not more than I do team dive so this may affect my perspective. I also don't buy into relying on a teammates gas or ever consider it in my dive planning. This is not to be confused with "Team BO" which is in no way what I am suggesting you are doing. As Forset, Rob, and a few others have mentioned we do prepare for multiple failures in an overhead. CCR failures are rare yet some of their failure modes require getting off the unit completely, others it can be uncertain if the units can still be used and it may still be prudent to BO. A fairly strong pattern of highly elevated RMV when bailing has been established along with incidents tending to snow ball from one problem to multiple ones. The skill level that a cave CCR diver should have, IMO, would make carrying two sources of BO compared to one a simple solution without added task loading.

[Randy Thornton]

**snip**



Randy,
Seriously looking for discussion here, not stirring the pot or anything. I'm having a difficult time following your logic. With OC solo diving most recommend carrying a BO cylinder as extra redundancy. When diving in a team OC most consider their teammates gas reserve as a back up to their reserves. Personally I won't go any farther with a teammate on OC or CCR than I will solo with the same gas set up. In fact the majority of teammates I will not go as far as I will solo. It is not a lack of trust, it is not knowing their RMV well enough, in all situations to include high stress to be sure of the gas reserves.

CCR is the same with my view point. I carry the same gases the same way I do solo when diving with a teammate. Also having a cylinder that is dedicated to donating while maintaining a cylinder that is for me to BO allows for someone outside my team needing assistance while not jeopardizing my own BO ability.

I solo dive as much if not more than I do team dive so this may affect my perspective. I also don't buy into relying on a teammates gas or ever consider it in my dive planning. This is not to be confused with "Team BO" which is in no way what I am suggesting you are doing. As Forset, Rob, and a few others have mentioned we do prepare for multiple failures in an overhead. CCR failures are rare yet some of their failure modes require getting off the unit completely, others it can be uncertain if the units can still be used and it may still be prudent to BO. A fairly strong pattern of highly elevated RMV when bailing has been established along with incidents tending to snow ball from one problem to multiple ones. The skill level that a cave CCR diver should have, IMO, would make carrying two sources of BO compared to one a simple solution without added task loading.

Hi Bobby,

Thanks for your post. Please keep in mind that I am not saying that it is unwise to split your bailout, nor am I implying that one should not carry sufficient bailout, whatever that might be in each individual situation. And lastly, I am certainly not implying that cave divers should depend on team bailout. In fact there are times that I decide for a multitude of reasons to split my bailout when the situation requires it. My only point is that just like diving OC, a diver should have redundancy of breathing gas. Having multiple redundancy is not always preferable. IMO, adding multiple tanks adds complexity to a certain level, even if the breathing gas is the same in all of the tanks.

Again, I am not criticizing those that choose to always split up there bailout, only that I don't believe it necessarily is a benefit in all situations.

Regards,
Randy

[FW]

..Again, I am not criticizing those that choose to always split up there bailout, only that I don't believe it necessarily is a benefit in all situations....

At the very least, it helps balance you

[Slüdge]

With OC solo diving most recommend carrying a BO cylinder as extra redundancy.

It's not extra redundancy, it's the first redundancy.

Although sidemount is self-contained redundancy, as is the use of independent doubles, manifolded doubles (which I dive 99% of the time) are NOT redundant. If there's a single place you can lose ALL your gas , no matter how unlikely (such as a blown isolator o-ring), it's not redundant.

I wouldn't feel like I was taking chances diving solo in sidemount or ID without a buddy bottle. But I wouldn't even consider diving solo with manifolded doubles only.

[Bobby]

Randy,
Thanks for your response. I see what you are saying and did not feel that you were criticizing. It is a good topic of discussion with many view points. Having had a few situations that seemed benign turn ugly I have come up with a solution that seems to work. You are right in that it is not needed all of the time, in fact it is not needed most of the time. It is the very rare situation that has come up and bit me that made me decide to carry my gas the way I do.

Thanks again for your input and open discussion,

[Bobby]

It's not extra redundancy, it's the first redundancy.

Although sidemount is self-contained redundancy, as is the use of independent doubles, manifolded doubles (which I dive 99% of the time) are NOT redundant. If there's a single place you can lose ALL your gas , no matter how unlikely (such as a blown isolator o-ring), it's not redundant.

I wouldn't feel like I was taking chances diving solo in sidemount or ID without a buddy bottle. But I wouldn't even consider diving solo with manifolded doubles only.

My apologies for not being more clear. Yes 100% correct on that. As I have not been in BM for a long time I don't think in BM configuration anymore. I look at BO a little different on OC SM as I am switching regs with OC and keep a closer eye on each of the gas sources. I check my BO regs and systems before every dive but often they are not touched for the entire dive unless I am removing the CCR. When I do remove the CCR I go OC until I put it back on and always check both regs to ensure they are fully functional. I do dive OC SM without a BO cylinder for the above mentioned reasons. CCR I do not for the same above mentioned reasons. I also won't push anywhere near 1/3's without another cylinder on OC even with SM. As of yet I have not had a bad experience from carrying more reserve gas.

[jj1987]

Do you not reserve more than just what that equation yields? That's cutting it extremely close should you have to exit under your own power and under duress. There really needs to be more reserved for both DPVs and rebreathers.

That function is relative to the sac rate you choose. I typically use a much lower sac for planning entry (to ensure I get where I plan to go), than I do for exit, where some level of panic might have set in.