I have the luxury of a lot of dives in Florida, Mexico, France and elsewhere. CCR is still in a huge minority in cave diving - as it is in diving as a whole.
For deep caves it is a tool of choice (although some of the deepest caves I've dived (Wakulla, Turner, River sinks, Indian etc) I have only been able to dive OC for access/team reasons.) For shallow caves like mexico it is an unneeded burden unless you are taking part in true exploration where particulate and gas logistics make it valuable. I can easily carry more gas than a scrubber will give me time and a scooter is a much more valuable use of luggage allowance there. Our dives in mexico average five hours and drift often towards six. Not much margin for getting lost on those regardless of your chosen method of diving.
I do giggle at those who say they would rather have sufficient gas to allow them to get lost. Come on guys, getting lost in a cave is unacceptable. Straying from your way or delaying your exit for 1-5 minutes is about as bad as it should get and carrying enough gas for that is no big deal.
I have done one cave dive out of 100s where having a RB would have made a delayed exit from a cave in zero viz less tense gas wise (we exited with 100 bar in doubles left but it didn't feel like we would at the time and the whole set was in reserve so we still blew through a fair bit). That was in completely and absolute zero viz (HID pressed to mask was invisible) so extended use of a CCR would have been problematic too with no verification of PPO2 possible.
On shallow cave dives they are a pita. My gas consumption is in single digits so two or three ali 80s and a set of doubles gets me up to 7 hours in many mexico caves. In most cases the end of navigable cave is hit far before any gas limit. In the Dominican Republic, we could have dived most caves we visited on a single stage!
Does this mean that there is no use for an RB in a cave? No of course not. They bring the same benefits and risks in a cave that they bring to sea diving. Gas logistics on individual dives as well as trips in more remote places, lack of particulate, gas extension at depth. In a way they are nicer on deep cave dives than deep wreck dives as you can stage bailout (but not if you get lost!). In shallow tourist caves they are good for photography, in less dived caves they are good for avoiding particulate and surveying. Using them in up and down shallow caves makes for pin point buoyancy practice (please think of the cave when practicing though and watch your dil consumption).
Mark, I know you are new to cave diving and have only been to Mexico twice. Exiting a cave can look different to the way in, turn occasionally to orientate yourself plus look for markers (not physical ones like cookies) like odd placements or rocks which are memorable. Make a time check as you do and then count back as you leave. If you want to drop a cookie do so, but if everyone did that the line would be full of cookies and they would loose their usefulness. Better to use a cookie than an RB though as a cookie won't kill you without warning.
I'll end on one last 'off topic' which is a personal bug bear of mine. I do not think people should be taught CCR cave before OC cave. I have a friend who was taught this and has so many misunderstandings about cave diving. He has not been encouraged to build up a mind map of distances at depth that he can travel OC yet if a CCR fails that is all he has. He returned from his class unable to tell me what his swim rate is, having instead been taught to swim in very, very slowly. So a cave map is no real use to him for time, gas or bailout planning and he has no experience to back this up with.
I am very old fashioned I guess. Apprentice Cave or Cave 1 allows students to get a small way in so they can learn cave diving without exposing themselves to complicated dives. Then after a time go back and get a full ticket. I moved quickly in my progression but only because I practically lived underwater at the time. I did over 100 dives at the first level before going forward. Whrn I got my full cave ticket I had 150 cave dives in three countries. I carried on in similar fashion. I did 100 dives in one cave before I first took a scooter in there. My first RB dives were in caves doing dives I had already done OC. I knew the travel times, the gas distances, the drop points. There is so much cave to see, even in the first 100 feet on the most well dived cave, so go slowly and look, enjoy the cave. Lay your reel, drop markers, see how long it takes you to swim slowly, how quickly you can do it if you have to get a move on. How flow affects your performance, where you can shelter from it.
If you decide to do one jump, do the jump. What is the line you jumped from like - is it gold line? What is the line you are jumping to supposed to look like? is it knotted, how far from the mainline was it supposed to be - are you on the right one?Mark it with physical things but also with your memory. Mark gas and time, remember the flow, picture the cave map and where you are on it. Don't feel you have to commit to the decision - if you are unhappy with the new line - turn around, pick up your jump and move on. If on consulting a map later you were right - well you get to do the dive again
If you dive like this you won't be worried about getting lost or running out of gas. Instead you will be enjoying the dive.
Rant over. Not aimed at anyone in particular or even a group. The fact that Mark has posted here is coincidence and he is not the friend I am talking of above. Just hope to get some newer or want to be cave divers thinking a little. Part of me enjoyed teaching cave, part of me couldn't live with an industry which had to earn a living from it pushing classes on people who were not ready. Zero to hero in six diving days? Ridiculous. The customer is not alway right as the customer does not always realise what they want is not good for them.
You may have 1000s of RB dives. Does not translate into caves though.
You may be a great CCR/OC instructor - does not translate into caves either.
Go slowly. RBs are dangerous but can be good fun. So are caves.
I found it hard to keep my mouth shut although professional standards required it. Now I don't have to
he's like a rat through a drainpipe.
