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Safety in Cave Diving

by Oliver Wells

The arrival of the Belfry Bulletin is always an agreeable moment and perhaps the efforts of the editor and of the regular contributors are too often taken for granted.  The happy feeling that this is really not my problem was ended rather abruptly in my case when I found myself talking to this hard-working gentleman in the Hunter's Lodge.  He reminded me that as a member of the BEC,  I was expected to put pen to paper and then send the results to him. So I was wondering whether some notes on safety in cave diving might be of interest.  Nothing that I shall say here is new, but I have a special reason for writing this article that I shall describe in a moment.

It has always seemed to me that there are two main schools of thought about training cave divers, depending upon the degree of mental strain that is put upon the trainee.  If you join the army, as many or us had to do in the 50’s, then you will find that the training is a rather 'heroic" process in which the finer sensitivities of the trainee are ignored.  In the same sort of way, when I signed up for an underwater course about ten years ago to see if I could still do it, I was dismayed to find that the instructor seemed to be a frustrated marine sergeant who scattered tanks across the bottom of a really quite deep indoor pool and then expected us to swim from one tank to the next, taking only one breath from a mouthpiece attached to each of them.  I have never been so close to drowning in by life.  I seem to remember that when I was taught to use an oxygen respirator by Jack Thompson and John Buxton in 1954 and 1955, the training was equally no-nonsense but was carried out in a more humane way (apart from the physiological tests, that is.  The dive store that I do business with these days follows the more humane approach also.

Possibly you may have realised by now that I do not like the “heroic” method for training divers, especially from the receiving end.  I prefer a more tranquil approach based on extended periods of time spent underwater gradually becoming acclimatised to the life below.  "Exercises" such as mask removal, mouthpiece exchange and so on can then be accomplished without any worry whatsoever (or can even become agreeable if you are on really good form).

An important question is how often you should practice your basic diving skills.  There are, it is true, certain individuals who have the unfair advantage over the rest of us in being able to perform underwater to perfection without regular practice.  But if you wish to be REALLY on form then you should go below the surface at least once a week.  In the 1950's I met this requirement by swimming in a flooded gravel pit while a helpful colleague rowed a boat from which a nylon rope came down from the sky, as it were.  Before my recent visit to England, I spent well over an hour following a thin nylon line laid between weights at a depth of about 9 feet in a lake behind a friend’s house.  Such has been the progress with diving equipment that neither a boat nor a safety line tied to the diver were needed.  While doing this, I deliberately stirred up the mud and very carefully kept in contact with the line at all times.  A colleague who tried to do this expressed surprise that the line could suddenly vanish completely, obviously you must concentrate your mind endlessly on this point.  After five dives at intervals of about a week I once again felt ready for a cave.  At the very least you should practice underwater within two weeks of diving in a cave.

Another important point is what I call the "safety reflex' of the diver.  If you are an open-water diver, then your idea of safety is the surface.  As a cave diver, your reactions must be totally different.  You should have two simultaneous responses if a sudden problem should arise.  Your first automatic reaction should be to check your back up mouthpiece.  Your second should be to check your contact with the line.  Then you can sort out your problem.

A friend who read the above paragraph points out that the more general idea is of "penetration diving" rather than cave diving if the above ideas are to apply.  His interest is diving on wrecks.  At one dive site, there is a wreck directly below the channel used by large oil tankers that sail by at regular intervals with their propellers churning and so on.  The divers lay lines from the side and employ all of the precautions described above.  (Wreck divers generally carry an independent aqualung supplied from a small "pony bottle' that does not have the duration of the backup system carried by a cave diver.)

Constant practice can pay dividends in many ways.  For example, during my recent swim back from Wookey Nineteen with Bob Drake, it seems that I did not tighten the belt that holds the cylinders around my middle to the degree that is required.  (That steep, restricted. muddy rock slope in Nineteen is not the most comfortable place for putting on cave diving equipment that I have ever been in.)  I knew that I was on good form when I went underwater and the lines appeared to be more "friendly" than the surface. About 15-20 feet along the line and while I was in a fairly compact section of the passage, the tube from the regulator on my right cylinder suddenly pulled tight so that the mouthpiece set off at a brisk speed in the direction of my lower right wisdom tooth (possibly the tube was too short).  It is amazing how fast the jaw muscles can tighten at a time like that. Unexpectedly perhaps.  I did not feel alarmed even slightly, and stopped swimming, checked the backup regulator, checked my contact with the line,  and THEN pulled the cylinder back to where it should have been (for the first of many times that I did so on what was really a very agreeable dive).

Of course, the episode described above was fairly trivial.  This sort of problem occurs to cave divers all the time.  I only mentioned it here to emphasise the need for constant underwater practice if you do not wish to be alarmed by such a thing. The final five chapters in Alan Thomas’ book "The Last Adventure" contain examples of happenings that were more dangerous than the above.  In my opinion and if you want to go cave diving, then you should read these chapters, think about these episodes and then practice underwater until you are confident that you can meet such crises in a totally calm way.  (And even then please do not be in too much of a hurry to “push the limits” until you have been doing it for some time.)

Crises that occur underwater can be all the more terrifying for being unexpected.  Tony Jarratt told me about a diver who was exploring in a mine working underwater, stirring up the mud as he swam along.  When it was time to return, he found that his line reel was jammed, and that he had been pulling the belay block along behind him. There was no line through the muddy water back to the air surface.  Tony tells me that he got out successfully.  It is a terrifying story, but is useful perhaps in emphasising that you cannot be too careful.

By “redundancy” we mean that if the respirator should suddenly stop working (or worst of all release its air) then you can change over to a second mouthpiece on a backup system and reach safety using your own resources alone.  Perhaps it should be emphasised that this is a MINIMUM requirement since such failures can and do happen.  For example, I had a friend In Pittsburgh who lost the O-ring between his cylinder and the regulator at a depth of 70 feet in open water.  In Hawaii.  I was in the boat when a diver emerged with a stream of bubbles coming from his pressure gauge.  About two weeks later, a diver right in front of me suffered a blow-out of some kind from the cylinder valve behind his head and then surfaced in a cloud of bubbles that was larger than any such cloud that I have ever seen.  One day when practicing in an indoor pool with a borrowed regulator, I was surprised when the rubber mouthpiece came off and I was connected directly to the water.  Oddly enough, in the 1950's we dived regularly in caves without any backup system apart from a second oxygen cylinder that fed into the same breathing circuit, and it is not clear to me looking back on it, how we could have felt so self-assured.  A totally independent backup system now appears to be absolutely essential, in my opinion.

In response to a question from a non-caving friend, cave divers nowadays wear a cylinder on each side ("side-mounts" in the current Jargon) with a pressure gauge and a regulator on each of them.  The idea is never to get yourself into a situation where you cannot get out with the backup system.

Head protection was neglected in the 1950's.  Bob Davies wore a beret over the very thin rubber hood on his dry suit with this idea in mind, but the rest of us did not even do that.  Nowadays cave divers always wear a helmet and with reason. The only question is how soon the use of helmets spread to open-water divers also, because even there the diver can (and sometimes does) knock his/her head.

Another question is whether it is safer to dive solo or whether you should maintain close and continuous contact with a second diver at all times.  Obviously it is a good idea to have a second diver not too far away, but it is a delusion to expect that he/she can help you if anything really serious should go wrong.  In fact, the chance of an accident underwater in a cave is probably increased if there is a second diver too closely in contact to delay you and generally cause confusion.  Solo diving can be very agreeable if you are on form (and yet I WAS very grateful to Bob Drake when he appeared out of the murk and unwound the guide wire from around my left regulator on the first of my two trips back from Nineteen --- although to be truthful about it, we were operating separately for all practical purposes until I was delayed at that point).

Here, the reviewer wrote: "All dive certification agencies emphasise the need to dive with a partner.  Your statement will be criticised ..."  Diving with a partner makes very good sense in a very large number of cases, but I still think that in cave diving the problems caused by a companion in continuous close contact in causing delays, stirring up mud and so on can outweigh the advantages.  Having a second diver not too far away can be very comforting, however.

Concerning deep diving when breathing air in caves.  I am against it.  In the late 1950's I went with John Buxton to HMS Vernon in Portsmouth where we went to the equivalent of 200 feet in a pressure chamber in company with some Naval Officers.  We sat on benches along the two sides of a horizontal cylindrical chamber of diameter about 5 feet while a naval gentleman at one end communicated with the world outside by hitting the wall with a noisy blunt object.  We stared at the needle on a depth gauge as it slowly rotated clockwise between us. There was nothing to report down to 170 feet, when nitrogen narcosis came on with about as much subtlety as being hit on the back of the head with a hammer.  It was a ghastly experience.  I felt as if I was being whirled in a centrifuge about ten times faster than I wished to go.  But the plan was to go to 200 feet, so on we went.  By this time the air was so dense that it was a major athletic enterprise to breathe either in or out, in addition to the narcosis.  The Naval Officer told us later about the incredibly stupid things that even experienced divers had done at such depths.  Cave diving, anyone?

(Generally, people who dive deeply in caves either practice endlessly to survive narcosis or use a different gas mixture to avoid its effects.  Dive certification agencies generally prohibit dives below 120 feet. In response to a question from the reviewer, the above took place entirely air.  Presumably it would have been worse underwater.)

Perhaps the final point that I shall make concerns the EXPECTATION of the diver.  Of course, all of us would like to be at the cutting edge of cave diving, and yet nowadays I have been forced by a certain feeling of reality to regard myself as being in the position of a tourist to the Alps who is conducted on an easy rock-climb by one of the local guides.  Of course, this does not excuse from the need to practice my skills, mental attitude and equipment (you cannot escape from this).  But in fact I find it not at all bad to restrict my ambitions in this way, and I find trips such as Three to Nine and the like to be enormous fun.

Oh yes, why did I write this article?  About six month ago I agreed to write a chapter on the history of cave diving (which is more difficult than giving a lecture because you cannot fluff over the difficult bits).  So this article is a partial dry run in an effort to de-confuse my mind on this subject. The style of my chapter will be somewhat different from the conversational tone I have used here.  So if the reader would like to help me by sending me any comments on the above (especially with reference to ORIGINS of these ideas or to alternative points of view) then I shall be very happy to acknowledge any such help in the final version.  Or perhaps the Editor might wish to receive such items directly – I know I would be very interested to read such things in the Bulletin myself.

Cave diving has a great future and it will be interesting to see how it is made safer as it continues to advance in all aspects of underwater exploration by human divers, by remotely controlled vehicles and finally by autonomous computerised devices that will explore and record data at distances, depths, temperatures, etc. that are far beyond anything that can be done now.