Teaching an old(ish) dog, new tricks


A really good friend of mine who runs a charter boat out of Florida has a wonderful phrase to describe divers  who are really set in their ways and somewhat complacent when it comes to dive prep. You may have seen them on a dive boat near you. They always dive exactly the same gear package, right down to the back-up lights on their shoulder harness, double cylinders, a stage bottle, canister light and a full complement of reels, spools, and sundry accessories; including a scooter.  Now he is first to admit there’s nothing inherently wrong-headed about that, except they dress the same regardless of whether the day’s target is a 150 foot dive on a brand-new wreck or a 25 foot bimble in a local quarry.

He calls them One-Dimensional Divers.

“I think they are so blinkered and taken with the self-importance of being a technical diver,” he says. “They forget to stop, smell the roses, and kick back!” He says that the real sign of a one-dimensional diver is that they can turn the simplest of dives into a major undertaking. “And where is the fun it that?” he asks.

And after 18 years of lugging a full North Florida Cave Diver’s rig around the country, and using it on even the most straight-forward dives, I felt I’d fallen into the one-dimensional mode myself. I told my buddy things had to change; and he offered the perfect solution. “Buy a closed-circuit rebreather.”

Working for a training agency gives an old guy like me a slightly off-kilter prospective on dive gear, dive travel, and the whole business of diver education. For example I figured I knew quite a bit about CCRs (closed-circuit rebreathers) because I have an instructor rating on a SCR (Semi-Closed Rebreather), have proofed rebreather manuals, and have logged lots of hours on several different CCR units doing everything from try-dives to bona-fide courses.

How wrong I was.

The seed change was actually getting a unit of my very own to look after. Not a loner, not one that a manufacturer suggested I take a look at, but one that I had to take apart, clean, keep spiders from visiting, change its do-dads from time to time, reassemble, and learn to dive from ground zero with the express goal of getting comfortable enough on it to drag it halfway around the world to dive the wrecks of Truk Lagoon.

To be blunt, it was one of the best things that has happened to me and my diving in a long while; and it certainly has also been among the most instructive.

The reasons for this are varied and many faceted but let’s keep things brief and simple and start with the whole one-dimensional / complacency thing. No matter how hard one works at keeping focused and realistic about skills, planning, only taking into the water what’s needed on the dive, and doing things to the letter, human nature has a wonderful way of turning short-cuts into “best practice.”

On open-circuit dives, it is very easy for an experienced diver to become one-dimensional. So much so that at times, dive plans for commonly done personal dives – ones that fall into the “I have done this a thousand times before” category – became marginally adequate at best. As little as it turns out I know about CCRs, I did know enough to understand that the one-dimensional / complacent approach will quickly get you in a very deep pile of trouble.

Occasionally doing something totally outside the norm, helps adjust one’s attitude. Training on and then diving a piece of kit that resembles nothing you are used to diving, definitely turns a few knobs.

As you know, a rebreather recycles exhaled gas, scrubs out the carbon dioxide, squirts a little oxygen back into the mix to compensate for the stuff used by the diver’s metabolism, and is designed to keep the process going for hours at a time. It also mixes gas so the diver breathes “best mix” regardless of depth and it does all this in a compact package (read this to mean, less weight than a set of doubles!).

The other side of the coin turns up the nasty little vagaries attached to rebreather diving, and understanding and working around these is the central theme of a rebreather class.

In short, a CCR can deliver too much oxygen one minute and not enough the next; both harbingers of a bad day at the office for any diver. The little chemistry set that extracts carbon dioxide from the breathing gas can suddenly stop working for all sorts of reasons; most attributable to user error, and again bad news all round. The unit can leak a little making breathing an awful chore, or it can leak a lot, flood and cease working at all; both of which are good reasons to bailout and go home with one’s tail between one’s legs.

All this of course comes as a real eye-opener to the experienced open-circuit diver who has been diving the same kit configuration since Reagan was in the White House.

My other eye was opened by our CCR instructor, a good friend who for that reason alone cut me and my buddies zero slack during the whole week we worked with him to earn our certs on the Pelagian manual CCR we had opted to buy.  He pushed us relentlessly and continuously picked up on any fuzzy logic we fell into using. He watched us with the eyes of a caffeine-crazed hawk as we prepared our units for our underwater escapades; and once in the water we were on a very short leash and ANY moment of distraction or deviation from our plan resulted in yet another simulated failure and drilled contingency action. In short, he treated us like the rank novices we were and took no account of the combined 30 or so years of technical diving experience, and technical instructing we had between us.

Actually, that’s a lie. He did make a special mention of all those open circuit dives we had made. And that was what brought things into focus. “You guys,” he told us, “are swimming in dangerous waters.” He explained that we had to understand and believe that we were right back to where we were when we first started diving open-circuit scuba. We had to plan and dive beginner dives again and not be tempted to think that it was ok to dive to 60 or 70 metres because we’d done that on open-circuit a thousand times.

“It doesn’t matter much,” he said, “how many dives you have or where you’ve been on open-circuit. That was the stone-age and is all in your past. You are starting with a clean slate now, and it’s important you learn to paddle around in the shallow-end of the pool before you attempt to swim the English Channel!” (He’s a Brit.)

Now here is the cool part. As soon as he let us loose with cards that said we were certified to dive without adult supervision, we starting to rack up the hours on the type of dives we had not done for years.

We went back to shallow wrecks we had ignored for more than a decade and a half. We planned weekends of multiple two-hour dives in sheltered little spots we would have swum right by if we had been diving open circuit. We relearned the simple pleasure of gradually working around a very much narrower comfort zone and competence level. We practiced bail-outs, we obsessed, we had great fun, and in the final analysis, we changed back to being a little more multi-dimensional in our dive planning and dive execution. I think it’s fair to say that becoming a weekend CCR diver, improved my OC skills.

Oh, and Truk Lagoon. Well, a story for another day, but we worked hard to build our competence and it paid off. What incredible fun to dive a CCR in that environment, even if we did opt to give some of the deeper wrecks a miss… you see, as far as the CCRs are concerned, we’ve only been diving a year.

5 thoughts on “Teaching an old(ish) dog, new tricks

  1. Your point about the value of CCR diving to your diving is oft-overlooked.

    There are “one-dimensional” rebreather divers too .. those to whom open-circuit is just for bailout :)

  2. You have a very good thought but let me add that CCR can give some danger like; high PO2, low FO2, hypercapnia or full flood.

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