Cave CCR?

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I had always heaqrd that CCR's are a no no in caves because of hte degree of penetration that exceeded the amount of support equipment normally used with OC.

Where have you heard that? There's nothing wrong with CCR in caves as long as you don't violate gas rules. That's also true of OC. Don't be an idiot, don't ignore prudent gas rules, and don't be an idiot....you're fine.

The issue is that plenty of people ARE idiots and can easily outswim/scooter their bailout. People get a little lazy/complacent and use that to justify optimistic gas planning. Same is true on OC.

I think CCRs make the most sense in a cave, actually.
 
I teach these programs through the NSS-CDS, TDI and IANTD so have the perspective of the standards from all three agencies.

There are basically two different "Cave CCR" tracks based on a diver's background.

Track 1 - "CCR Cave Full Course" -- Diver background: CCR diver with at least 35 hours, zero (or minimal) cave diving experience. This is typically a "zero to hero" program that should be 7 or 8 days in duration. The purpose is to train the non-cave diving rebreather diver to be able to conduct safe cave dives. For the most part, all of the skills presented in a typical OC cave course (running a reel, tying into the guideline, navigation, lost vis, lost buddy, lost line, air sharing, etc) should be included in this course PLUS the CCR cave diving skills (proper bailout planning, variable SCR mode, etc). At a minimum, the diver should have spent around 600 minutes diving as part of this course, and it's likely that they will spend closer to 800 minutes (just shy of 15 hours in a week).

Track 2 - "CCR Cave Crossover/Upgrade" -- Diver background: OC full cave diver, CCR diver with at least 35 hours. This is typically a 2-4 day program, agency and instructor depending (TDI requires the person to do the "CCR Full Cave Diver" 4 day program), that should reinforce the basic skills from OC cave plus teach/introduce the CCR cave skills. Although I've taught this course in as little as 2 days, that student was an outlier (see comment in next paragraph) and I believe it should generally be a four day program because one full day is typically spent just getting the gear squared up.

I have a lot of friends that believe Track 2 isn't really necessary if the person is an experienced OC cave diver and an experienced CCR diver. They believe an OC cave diver should have a good working knowledge of gas calculations, etc and a CCR diver should have a solid foundation on the necessary CCR skills. While I intellectually agree that OC cave divers and CCR divers should have solid foundations in these areas, about a year ago I had the opportunity to teach the course to a pretty accomplished explorer (a guy that at one time held the end of the line in Manatee, Madison, and Ginnie, all at the same time) and he told me he learned some valuable stuff in the program. FWIW, GUE will soon be launching a CCR cave program because they realize there are some valuable skills in CCR Cave that aren't really emphasized in Cave 1 / Cave 2 and their CCR program.
 
There are some caves which require a full cave card - ie Grand Cenote in Tulum. My cave ccr card wasnt good enough, nor was my cave dpv card, nor was my overhead sidemount card from Edd - they wanted a full cave card nothing else.

Having said that I enjoyed doing the cave ccr crossover. Working out bailout needs, staying on the loop drills, going semi closed, having my ass kicked due to buoyancy differences between OC and CCR were all useful learning experiences. Just as I was getting comfortable and thinking I had a handle on things - buoyancy, trim propulsion all good on CCR we would then go on a dive like Waterhole or Double lines which go more up and down. I swear my instructor would suggest them just to bring me back to reality of the schmuck that i was.

As Peter/Superlyte said you can start cave ccr without full cave (you just wont get into Grand Cenote).

For the cost of training Cave CCR was a great investment.
 
There are some caves which require a full cave card - ie Grand Cenote in Tulum. My cave ccr card wasnt good enough, nor was my cave dpv card, nor was my overhead sidemount card from Edd - they wanted a full cave card nothing else.

Having said that I enjoyed doing the cave ccr crossover. Working out bailout needs, staying on the loop drills, going semi closed, having my ass kicked due to buoyancy differences between OC and CCR were all useful learning experiences. Just as I was getting comfortable and thinking I had a handle on things - buoyancy, trim propulsion all good on CCR we would then go on a dive like Waterhole or Double lines which go more up and down. I swear my instructor would suggest them just to bring me back to reality of the schmuck that i was.

As Peter/Superlyte said you can start cave ccr without full cave (you just wont get into Grand Cenote).

For the cost of training Cave CCR was a great investment.


I think you have a good point that a CCR Cave card may not be universally accepted and I'm a believer that the best way to learn to be a CCR cave diver is with some of the training on OC first and then CCR.

If a person travels for a cave diving vacation and something happens to their CCR on day 1 that isn't easily repairable during their vacation, such as a complete electronics death, are they going to say "well my dive trip is done" or do you think they'll switch to diving open circuit? I suspect many of them will switch to OC, but wait, they weren't trained for OC cave diving...
 
@jstrang that's a new one that I haven't seen yet.

@kensuf in your example, do you think that having say cavern/intro done on OC with some experience in between, then going to CCR Full cave with TDI for their 4 day course would be sufficient?
 
@KWS quite the opposite, CCR's are brilliant for caves, just don't think that you can ditch all of your OC stuff for obvious reasons. If you are doing straight linear penetration and the goal of the dive is to just get to the end of the line and come home, you aren't going to save much of any gear by going to CCR. You take ~20% of your gas away because you aren't consuming much on penetration, but you still need the other 80% to get home. One dive per site where you are going to the end and back? Doesn't make any sense to bother with a CCR unless it's REALLY far back or trimix depths.
Where it is brilliant is when you are doing multiple dives in the same cave and can just leave the bailout bottles in there until you are done. Saves a lot of hassle in the middle bits. It also is brilliant when you are poking around. A regular dive plan for me is to get to the farthest point of penetration relatively quickly, then take my sweet old time on the way home. I can branch out on any jumps that I want, spend an hour in a single room if I wanted, etc. and not have to worry about gas because I haven't exceeded maximum penetration.

There are two things that changed cave diving for me completely. The first one was helmet mounted small video lights. Removed the tunnel vision that primary lights give and just made the experience better. The second was the CCR. It removed the "tick tock" of time pressure for me and allowed me to go REAL slow which I like. IMO it is an ideal tool for cave diving....
I can see that normal penetration and having long stay time like in a ball room etc in one thing but a extended length is another.
 

Where have you heard that? There's nothing wrong with CCR in caves as long as you don't violate gas rules. That's also true of OC. Don't be an idiot, don't ignore prudent gas rules, and don't be an idiot....you're fine.

The issue is that plenty of people ARE idiots and can easily outswim/scooter their bailout. People get a little lazy/complacent and use that to justify optimistic gas planning. Same is true on OC.

I think CCRs make the most sense in a cave, actually.
It was a long time back when CCR's were not used in cave. the reason told to me was that CCR's alllowed you to go too far to recover from a failure. with Back gas you used 1/3 in and 1/3 out. with the CCR you were an hour in and then stuck if the unit failed. Much like the concern with using a dpv you could put your self is so far when you got to 1/3 that you did not have enough gas to get out if the scooter failed. Clearly there views have changed but long ago they were there.
 
I can see that normal penetration and having long stay time like in a ball room etc in one thing but a extended length is another.

Extended penetration requires more bailout planning. That's really the only difference. I think you're overthinking it. Plenty of long, deep dives are done on CCR. Plenty of cave is too far from the surface to explore on OC.
 
@KWS it's all about logistics when doing extended penetration as @JohnnyC and I tried to outline. In OC long penetration dives, you have to breathe the gas both in and out. Pick some BS numbers but say an AL80 is good for 1000ft on OC with you breathing a third in/thirdout/third reserve, you determine it's good for 1500ft on CCR based on the same parameters, and have a 10,000ft penetration. Your primary backgas/bailout is say LP85's which are comparable to 3x AL80's.
That dive says on OC, you need 7x al80's+LP85's, on CCR you need 4x 80's + LP85's. Essentially save 1 bottle since a CCR is comparable to a set of doubles. Looking at bmccr only for this.

For the OC dive, you could do a setup dive in a couple ways, but the way I would do it is to drop a full AL80 every 1500ft and drop 4 of them as safety/bailout bottles, same as you would on CCR. For the CCR diver when your doing the actual dive, you have the CCR and a pair of LP85's and you're done. Everything else stays in the cave and happy days. For OC, you need the LP85's, and still need to carry 3x AL80's for penetration to drop off when they hit 1/2+200 ish. Bit more complicated with bottle drops, gas switches, etc.
If something goes wrong on the CCR, you still may not have to touch those al80's though because you have SCR mode which can get you a 10x or more gas extension. You stay on the LP85's the whole way out and happy days.
If something goes right, you can still poke around on any leads or jumps on your way back. You have safeties out to 6000ft, and as long as you don't exceed your 10000ft total distance from home, and/or 4500ft from the gold line, you can go wherever you want in that cave.


On your example of why it was explained that they're unsafe. It sounds like it was explained by someone who never did actual gas planning and tried to use similar rules of thumb like we use with OC. So many cave divers did 1/2+200 and didn't touch their backgas which works with 2 stages and 104's on a Gavin or UV26 going 200fpm, many others did 1/5th's which works with the same scooters. That "rule" doesn't work on an XK1 or a Magnus going 250fpm. Those same divers tend to not have any idea what their actual sac rate is, or what their actual kick speed is and started using all sorts of "rule of thumb" kind of tricks for gas planning instead of actually doing the math.
DPV's and CCR's allow you to exceed your bailout gas, but to @victorzamora 's point, only if you're an idiot that doesn't actually do the planning ahead of time. Do it based on distance markers or known points on the map if you have them, also know how to do it based on time if those aren't available *have to know how fast your scooter goes and how fast you go though*.
Frankly I think DPV CCR cave dives are a lot safer when planned properly than kicking OC dives to the same penetration distance and you certainly get to a point where the distance/depth makes OC more dangerous from a quantity of gear perspective
 
Extended penetration requires more bailout planning. That's really the only difference. I think you're overthinking it. Plenty of long, deep dives are done on CCR. Plenty of cave is too far from the surface to explore on OC.
I agree totally.... that level of planning was not as neccessary with back gas. new technonlogies new problems new solutions. Ive never used one but CCR sure seems to be the way top go,
 
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