HOW CAN I EXPLAIN THE ATTRACTION OF WET ROCKS?

OTHREE DRYSUITS

A LOVE LETTER OF SORTS…
Somewhere on the simple, spiral DNA roadmap that each of us has inside every cell in our body is a tiny snippet of code that connects us to the desires of our first human ancestors; and beyond. And somewhere in that snippet is an even smaller piece of ageless programming that yearns to belong to the sky. Secretly, and deeply in our cultural past, we envy the birds, and crave to soar above this beautiful planet and for a short while, escape the relentless pull of gravity.

This lust for flight is hardwired in each of us; it is innate, nobody is immune to it. In a few of us, the appeal, is so strong we are driven to do extraordinary things to satisfy it. I choose to cave dive; and rather than giving into that desire, that hunger for flight, by soaring above the Earth, she allows me to float inside her; deep in her underground rivers; her canyons; her dark spaces. She has shared with me her secrets, and I love her for allowing me to enter into those places, to see her wonders, touch her delicacy, become lost in her beauty.

The principles of diving are simple. Basic physics manifest in weightlessness. Water supports us. With practice, we can hover in the water column without effort. With practice, we can spin, turn, glide, soar, dive, and somersault with a carefully applied and skillful flick of our feet. The cumbersome equipment we require to be comfortable, to see, to navigate, and to breathe in water disappears and we experience a unique freedom. We really can become one with the water; one with the earth. This is a form of worship.

In clear water the overall sensation of this experience is of flight; we are flying. The ocean offers this, but caves are, for me at least, more compelling, and the water in many caves is a clear as Evian water. The sensation of flying is within easy grasp.

The features of a cave — its decorations, its furniture, its rooms, cathedrals, crawl spaces, and sculptured, fractal surfaces, float by. Art. Just art.

So caves are special, and cave diving is a privilege extended to few. It is a small club, and membership can be expensive. Earth is a jealous lover. When she accepts you and allows you inside her, she expects your total respect and monogamy; an odd resentfulness of other mistresses. I have buried too many friends whose lives have been snatched from them for no greater reason than for a brief instant, they forgot to tell her how much she meant to them, they became complacent, they forgot to be gentle with her, and forgot to submit to her vanity and ego; they did not comply to her rules. And she allowed them to perish.

Perhaps all cave-divers are running on borrowed time. I cannot say. I have given in to the Earth’s fatal attraction. I have stopped worrying about that; I have been lucky. She allows me to woe her and accepts my devotion. She has guided me, and watched me fly through places no other human has seen. I have hung motionless except for the beating of my heart, loud and persistent in my ears, and looked at scenery veiled in darkness since the beginning of time; a place that has never allowed any other human to look at it. The Earth and cave diving have given me this.

And yes, it is only wet rocks, but to me this scenery is as beautiful as any reef, any wreck — and god knows the temptation to be unfaithful is present in them — however, reefs and wrecks are simply platonic relationships; pleasant dates, a brief press of the lips at the end of our time together. Caves are the object of a deep, visceral, want; a lust; a true love.

And you, my little Barefoot Forest Imp, understand and forgive my infidelity; and for this gracefulness, I adore you too.

How to get the most from a technical diving program/course

LongO'THREE

A common question is “What skills should I practice before my class with you?” The question is basically the same regardless of the course in question: intro-to-tech, full cave, it doesn’t seem to matter.

Oddly enough, the least helpful answer, is to send out the list of skills published in the instructor’s guide, and nothing else. Well, I guess it’d be less helpful not to respond at all, but a bare list of skills without any guidance, order of importance, value, or expectation of performance, doesn’t really tell much of a story; and certainly, is unlikely to help anyone prepare in a meaningful way. For example, what does adequate predive planning (taken from the standards for a major tech agency’s Cavern Course) mean in the real world?

If you’re signed up for a technical diving class this winter, next spring or whenever, and you’re wondering how best to prepare for it, the following tips may help.

First: if you haven’t already, speak with your instructor. Ask them about the class, get an agenda… what happens on day one, day two, etc. Ask for a breakdown of what they expect you to show them on each dive. Ask about their expectations regarding performance… what’s a pass, what’s a redo? Find out how much course time is practice time!

This last point is vitally important. A good class with lots of inwater time, will get you started on the road to building good habits. For example, the key to success in an entry-level cave or advanced wreck program is having enough time doing dryland drills to get the subtleties of a task – such as body position, where to point a light, how to hand off a regulator – refined enough to demonstrate well.

Secondly: study the equipment list, work out what’s gonna be a new experience for you, and practice how to use it. Reels – essential in so many tech programs, especially cavern, cave, wreck, and deco – are not all created equal, and even students who have first-class models, get screwed by their reels almost as soon as they get into the water. If you’re determined to buy BEFORE you start the class in order to get some practice, think simple and avoid gadgets. Here’s a model I use and recommend.

lightmonkey400

Also, most reels – including the one from Light Monkey shown above – come from the manufacturer loaded with too much line. It swells in water and with use, and falls off the edge of the spool. Take off line until there’s a half centimeter minimum of reel’s (or spool’s) body showing above the line. Here’s a picture of mine…

mylightmokey-200Notice, it is a similar reel (this is the 200 and the 400 is shown above), same manufacturer, but with line removed and a loop of equipment line added for the double-ended clip to make it hang a little more easily when stowed.

Also, learn where the new gear is going to be stored. Develop the muscle memory (the habit) of knowing how to get at it and then how to restow it. Every cave instructor has watched as one of their charges spends minutes searching for a line marker or struggling to stow a backup light.

Thirdly: relax. Arrive at your class rested and ready to learn.

And lastly: There is something called “instructor-induced narcosis.” It sometimes kicks in as soon as a student’s head disappears below the surface. Most instructors are expecting it to happen, and it usually has more of a negative effect on the student than the instructor. So, don’t sweat it! Take a deep breath, work out where things went wonky, try again.

Most of all, remember grow your skills, experience, comfort zone at your pace… and have fun!

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A thought experiment concerning “team bailout” when diving CCR in a cave…

LongO'THREE

First off: Can anyone explain the rationale behind “Team Bailout?”

Hang on… that needs to be rephrased.

Let’s start with this: Is it just me or is the concept of “Team Bailout” for CCR Cave Diving just bat-shit crazy?

Yea, that’s way closer to what I was thinking…

Ok, for those of you who may not be familiar with the team bailout concept, it suggests that a buddy team diving CCRs in a cave environment – you know, wet rocks, hard limestone overhead, perhaps an hour or more from the surface – that they carry sufficient bailout gas “…to get one team member back to fresh air from the point of furthest penetration.”

In certain circumstances, this approach may sufficiently protect team members from harm, but those circumstances should not include the category of diving the vast majority of us engage in.  I believe, a better, more satisfactory practice is for EACH diver to carry MORE gas than is required to get themselves back to fresh air from the point of furthest penetration.

The arguments I’ve heard against using this more conservative tactic is: 1) carrying multiple bailout cylinders is a pain; 2) the likelihood of more than one CCR failure among a team is too slight to consider; 3) calculations for the volume of gas required in a high-stress situation adhere to a well-defined formula corrected for all variables, and therefore it is possible to calculate with a degree of accuracy sufficient to be safe.

Experience is a better guide to best practice behavior than deductive logic, and I have limited experience in this area. So, perhaps my paranoia is unjustified; but here’s a scenario we might all give some thought to before our next cave dive.

Here goes:
Three CCR divers were in the back of a low-flow cave. Each carried an aluminum 40 filled to capacity, which lumped together was enough gas to get any one of them out of the cave and back to dry land. Even at double their normal consumption rate, this was the case. Their dive was well within the parameters of team bailout therefore.

At the worst possible time, Diver A’s CCR went belly up. He could not revive it in any way, and has to bailout. The team began its swim out. A little sooner than expected, but still more than one-third of the way out, Diver A’s bailout cylinder was empty, and he asked Diver B for her cylinder. She suddenly realized that by giving it up, she will have no contingency gas herself. The surface was still a good swim away. Very reluctantly, she handed over her bottle. Momentarily distracted by her thoughts, she floated to the cave’s ceiling and took a minute to recover, which held the team’s progress to the surface still further. Stress levels in all three team members was now peaking. None of them was comfortable.

They were in fact, more small failure, one additional glitch away from a total melt-down. A surprisingly short while later, Diver A – who had been thinking for the past several minutes, what would happen if he got a bottle with a dodgy regulator or had a free-flow, and whose respiration rate had understandably elevated – once again was down to seeds and stems. This time in his second bailout. He turned to Diver C. Diver C had been thinking about this hand-off for a while. He was VERY uncomfortable donating his gas… however, he did so. Several minutes later, the team arrived in the cavern area. Diver A had barely sufficient gas to conduct a safety stop, but did so. Just as the team left the overhead, his regulator began to breath very, very hard.

On shore, while shucking their gear, the group was uncharacteristically silent, each with their own thoughts. What do you think the outcome of this incident was:

  1. This group did not cave dive together ever again
  2. This group rethought their bailout strategy
  3. This group  continued to dive team bailout

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Don’t even think about asking for an overfill in your aluminum cylinder…

LongO'THREE

I don’t trust the integrity of aluminum scuba cylinders… at least, not enough to:

  • overfill any aluminum cylinder (in fact I often under-fill aluminum stages and decompression bottles keeping below the manufacturer’s suggestions for working pressure);
  • keep them in service more than a year or two after their first hydrostatic test cycle (which is every five years where I live);
  • wander very far from a very conservative approach to the frequency of formal visual inspections, choosing instead to follow the manufacturer’s suggestions for cylinders in Heavy Service;
  • miss Eddy Current testing as part of the VIP procedure (EVEN WITH BRAND NEW CYLINDERS!);
  • be trusting of loners and rentals, especially those with the look of being in service since, and taking direct hits during, the Gulf War.

My reasons for being a “mother hen” are based on a professional ‘cover everybody’s arse’ strategy to risk management. And a certain knowledge that high-pressure vessels have an enormous potential to harm. I’ve witnessed the aftermath of two separate aluminum tank failures and have a very strong mental image of the chaos each caused. I read somewhere that the amount of energy stored in a “recreational scuba cylinder,” which one can take to mean an aluminum 80, is about the same as two WWII British military hand grenades. A sobering thought.

Of course, one should be equally cautious with steel cylinders, which have a similarly dangerous potential. However, aluminum cylinders more easily carry the scars of mild to moderate abuse in typical everyday service. Couple this with their inherently different reaction to repeated filling and emptying – aluminum’s fatigue limit – and the dramatic reduction of an aluminum cylinder’s endurance limit from several hundred thousand fills to perhaps hundreds when it is over-filled – and its potential for failure is increased.

Of course, an easy out would be to avoid using aluminum cylinders altogether, but the buoyancy characteristics of aluminum makes 80s and 40s excellent stages, bailout, and decompression bottles. Besides, avoiding their use would be a dramatic over-reaction.

Working within manufacturer’s limits and the handling guidelines they supply us, aluminum is safe for many, many more fills than any of us is likely to ask it to endure.

But we do need to be mindful of those limits and guidelines.

Luxfer, the manufacturer of a popular brand of aluminum scuba cylinders of all sizes including the ubiquitous aluminum 80 writes the following about safety and its products… all great advice!

“If the cylinder is used in heavy service then it should be inspected every four months.

“Heavy service” means any one or more of the following:

  • Cylinders being filled or “topped off” five or more times per week;
  • Rental cylinders in use during the ‘season’ and ‘off-season’ times;
  • Cylinders used wherever damage is more likely than in normal use or where the
  • care and/or maintenance is slightly below recommended care.

If the cylinder is known to have had any unusual treatment or condition, it should be immediately visually inspected, prior to its next use.

“Unusual treatment or condition” means if the cylinder:

  • Dropped, fell, was struck, was in an accident, or when the care and maintenance of the cylinder is obviously poor;
  • Was stored improperly, and shows signs of damage;
  • Has obvious corrosion since the last visual inspection;
  • Has a gouge, dent, scrape, cut, dig or, in any way, has been damaged since the last
  • visual inspection;
  • Was stored with water, material or matter inside the cylinder;
  • Shows signs of exposure to fire or high heat, including any one or more of the
  • following:
    • Charring or blistering of the paint or other protective coating;
    • Melting or charring of the metal;
    • Distortion of the cylinder and/or any cylinder accessory;
    • Melting of fuse plugs, valve handwheel, valve protector, and/or any other
  • valve component or cylinder accessory;
  • Has been partially or fully repainted or treated to hide damage and/or
  • fire damage;
  • Is known or suspected to be leaking; or,
  • Is known or suspected of having a crack.”

 

Dive Safe… be careful out there.

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Fixing a lack of skill with complex gear… Nah, try a swimming pool!

Nick Hollis in SMS75 Hollis SM harness

Nick Hollis of Hollis Gear showing some skills in swimming pool like conditions…

Few of us learned to dive without the help of a buoyancy device of some sort. Not to say that wearing a jacket-style BCD, sidemount harness, or backplate and wing automatically gave any of us pin-point control over our position in the water column: it certainly did not!

The vast majority of the divers — sport, technical, rebreather, open-circuit, whatever — earned that particular skill with patience, perhaps a little help from a buddy or mentor of some description, and a bunch of practice.

Swimming pools or ‘swimming pool-like conditions’ (warmish, reasonably calm, clear-ish, current-free shallow water), are awesome for gaining something approaching buoyancy control right from the first open-water class: and then fine-tuning that skill by return visits as often as practical. I will still take time, whenever I can, to simply “hang about” in the water. A visit to the pool is a great place to test new gear, adjust weighting, check that old favorites still work the way you want them to.

In fact, if you are an instructor looking for ways to increase student comfort, add to general diver safety, and build on the basic skills your students learn on your courses, you’d do well to offer a few extra hours of pool time regularly. I have a buddy whose open-water students leave her classes with demo-quality buoyancy control and near-perfect ‘cave trim.’ Her secret is additional pool time, which her students gladly pay a little extra for because she’s taken the trouble to explain the benefits of buoyancy control to them. They get it: they know it takes a bit of work: and they are not looking for a fast fix.

So, imagine my disappointment to see an ad for a piece of kit that is such a convoluted bunch of “Heath Robinson” engineering that at first I thought it a joke. The product, and it is real apparently, is pitched as: “An industry standard premium diving jacket, dive computer with connecting links to allow the computer and jacket to manage diving processes according to the selected settings just like an aircraft autopilot.”

What have we come to when the simplest of devices, and a little practice to master its use, has to be replaced by something with Catastrophic Failure (or something else with the initials C-F) written all over it.

Please, if you want to get your buoyancy squared away because it wasn’t taught to you as a beginner, take a cavern or intro-to-tech class from a good instructor. Contraptions that offer instant mastery through technology are like magic pills that promise to shed pounds of belly fat without diets or exercise. The word to describe this type of promise is bullshit.

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A rare honor for a dear friend

explorer-in-residence-jill-heinerth-1

Jill doing what she does…

Someone once told me that as a community, technical diving suffers from a lack of real role models. He said that’s is not that there is a particular lack of great projects going on, or important discoveries being made. “There’s a tonne of great news out there!” he said. “It’s just that the news and personalities behind it are quashed by infighting and jealousy…”

That’s a pretty damning, really bleak commentary, but during the many years that have passed between him saying it, and now, there have been times when I’ve been inclined to agree with him. However, today, the technical diving community got some great news, and perhaps we can all be a little pleased… and proud.

Jill Heinerth has been appointed EXPLORER-IN-RESIDENCE by The Royal Canadian Geographical Society. This is a first, and to quote from the RCGS website, the “Explorer-in-Residence Program [is intended] to foster greater awareness among Canadians of the expeditions and field research being carried out by the nation’s top explorers, scientists and conservationists.”

Now that is cool, I don’t care who you are… that is awesome.

Immensely pleased and proud to call Jill a friend, and to say that she and I have worked on a couple of projects together… and she helped to make them fun, safe, and productive.

Hope you will join me in wishing her all the best, and giving her what really is a well-deserved pat on the back… and perhaps a glass of nice red wine!!!

http://www.canadiangeographic.ca/blog/posting.asp?ID=2070

Want to ignore the rules? Then do this…

There really are no scuba police, and here in most of North America at least, government bodies give the diving community the closest thing to a free-rein. We can, in essence, do exactly as we please. We can dive without training, ignore warning signs, flaunt best practice, exceed both whatever certification we have and the experience earned on previous outings. We are free agents. Great stuff.

But the downside is awful. A couple of days ago, I read of another stupid death — highly preventable and caused by several breakdowns in the system… that tragic alignment of holes in the safety net that which is in place to help diving “accidents” NOT happen.

What’s frustrating about many of the deaths we read about online, in diving magazines, and in diving forums, is that the people involved had been warned. At some point, either in their training or general involvement with the diving community at large, they had been told what they had planned, was foolhardy or against best practice.

But they went ahead anyway.

Just as sad is that their behavior does have the potential to change the status quo. Their silliness may create a situation where some agency or quasi-government entity starts to pay attention to our activities… and arbitrarily start to shut things down.

I am reminded of something my mate, Wayland Rhys Morgen suggested for anyone who is about to — either figuratively or actually — hand their beer to someone and say: “Here, watch this…”

The next time you intend to deviate from best practice, take a piece of note paper and divide it into two columns. Write in block letters at the top of the left-hand column: “What people usually do.” On the right, also in block letters, write: “What I am going to do instead.” Then in the appropriate column write clear, concise language an explanation of each behavior associated with your planned dive. So, these ‘behaviors’ would cover things like analyzing and labeling gas cylinders, limiting depth and duration according to your training, recent experience, and the vagaries of the environment… stuff like that. Read it back to yourself — both columns — then sign and date it. Then give it for safekeeping to someone you trust: lover, spouse, son, daughter, best buddy, favorite cowgirl. It really does not matter much to whom, just hand it over. Tell them to give it to the people or agency that leads the inquiry should something bad happen to you on your adventure.

Building the odds in favor of a good outcome…

LongO'THREE

A simple tip from the closest thing you’ll find to an expert

I have one of the best jobs imaginable… I get to dive for a living. It has drawbacks just like any job… I spend a lot of time away from home and the people I love; sometimes I am compelled to jump into the water when all I really want to do is sit on my arse and veg out; and there are few constants in a very fluid and organic field of research about diving, which means lots of reading, lots of lectures, lots of changes in what we teach and what we reject.

However, there are also a bunch of positives… including the list of things on the drawback list: I travel, I dive a lot, I get to feed my brain new stuff all the time.

One of the best things though is the people I meet. The so-called technical diving community is packed with cool folks. These are the men and women with open minds, boundless curiosity, and a willingness to share what they’ve discovered. They are stellar human beings and it’s a gas to hang out with them, and learn from them.

One guy who always has something interesting to say is Dr. Neal Pollock. Neal is ex-pat Canadian scientist. He’s a research physiologist working in the States, and has a background in zoology, exercise physiology and environmental physiology. He is also a diver and part of his research relates to decompression stress.

He also has a very “English” sense of understated humor in his writing and presentation style which appeals to me. I particularly appreciate lines such as: “The approximation of decompression status predicted by current deterministic algorithms should not be confused with ‘truth.'” Honest, insightful, and funny.

Anyhow, his latest blog is a hugely interesting read. It’s entitled “Flexible Control of Decompression Stress” and you’ll find it here: https://www.shearwater.com/news/flexible-control-of-decompression-stress/

Take the time to visit and read. You’ll learn something.

Surviving the Rottweilers

LongO'THREESeven tips to help protect you when things go wonky underwater

You may have read somewhere that underwater emergencies are rare. I’m not so sure that rare is the best way to describe them.

While underwater incidents causing bodily harm or death may be infrequent, close encounters with potential disaster are frightenly common. Spend a week or so at a dive resort or on a live-aboard, and you’re guaranteed to hear stories that support this view. “I ran out of air,” “we got separated from the guide and had no idea where the boat was,” “We ended up way deeper than expected,” “My computer went into deco and I had no idea what to do,” “My regulator started to spew bubbles and I panicked… I did not know what to do,” “We skipped our safety stop,” “I felt odd and confused, but managed to hit the inflate button and shot to the surface,” “I signalled the divemaster but he misunderstood me and continued with the dive.”

‘Victims’ of these little brushes with catastrophe fall into three categories. Some give up diving altogether. They get the crap scared out of them and opt for golf, fishing, stamp-collecting. No foul.
Some learn from the experience and avoid the traps that painted them in a corner in the first place, and they become more informed and safer divers.

And some learn nothing. They carry with them the potential to make similar mistakes again and again… sometimes with ruinous consequences.

Here are seven strategies that may help divers enjoy their diving, and avoid becoming a statistic.

      1) Learn to say no! Too many new divers are fooled into believing that it’s OK to do trust-me dives with a dive guide or divemaster. They may have a good sense that diving once or twice a year does not prepare them for a 40 metre-plus dive (that’s 130 feet or more), in current, with rented gear, but a divemaster, instructor, sales-person talks them into doing it. This is dangerous bullshit. No agency condones this type of practice, but it is common in many dive resorts, and needs to be stamped out.

 

      2) Learn your limits and stick to them. There is nothing wrong with pushing yourself to learn and grow your diving experience and comfort zone, but be realistic about your starting point. Being an occasional diver means you start from zero at the beginning of every dive trip. Scuba skills are perishable. Even experienced cave instructors take the time to “brush up their skills” if they have been out of the water for a while.

 

      Even if you are lucky enough to dive every week, understand that your experience, training and gear limits the types of dives that you can safely undertake. Listen to your inner wimp.

 

      3) Learn self-reliance. Too many “rescues” end up in disaster or near disaster for all participants. Get training, learn what kit to wear to help deal with gas emergencies, PRACTICE. Most of all, STOP, THINK, ACT, REASSESS.

 

      4) Maintain your kit, and use a checklist when you assemble it and when you inspect it prior to EVERY dive. Equipment problems are the easiest underwater emergencies to avoid. Don’t fall into the trap of believing that something is good enough… if it “ain’t perfect” don’t dive with it.

 

      5) Plan your dive… Dive your plan. Understand the risks, make sure everyone is capable of doing the dive, and ensure everyone have the skill and kit to deal with contingencies should they arise.

 

      6) Be aware! The best way to deal with a diving emergency is to stop it before it gets out of hand. The vast majority of diving emergencies begin as small inconveniences that cascade rather like dominos falling over. Keep an eye on your buddy(ies), be aware of changes in the conditions, monitor yourself. The best blanket advice is to take things slowly.

 

        7) Have an escape strategy. When something goes pear-shaped, the top priority is to make sure everyone has something to breathe… next is to get yourself and your mates as far away from the spinning fans as possible. Cave divers talk about always having a continuous guideline to the surface. Sport divers can take a lesson from that: Always know the location of a safe, protected exit… in other words, someplace where you can surface and be found or find your way to your entry point.

Steve Lewis is an explorer and experienced cave diver, who has been teaching technical diving programs for more than 20 years. He writes and lectures on topics related to diver safety in North America, Europe and Asia.

Adventure Tourism “Under the Bell”

LongO'THREEDiving Bell Island Mine

In 2006, while visiting Canada’s newest and easternmost province to dive on four excellent WWII wrecks, I was asked if I had any interest in leading a small expedition to check out the flooded Bell Island Iron-ore Mine in order to help determine if it had the potential to become an adventure dive destination.

In January/February of the following year, that expedition laid around two kilometers of line, discovered countless artifacts and items of interest. We also lost a valued team member during the exploration. Despite Joe Steffen’s untimely death, our final report recommended the opening of portions of the mine to qualified divers.

Unfortunately, during the intervening years, Bell Island Iron-ore Mine has not been added to the list of North America’s ‘must-visit’ dive sites. The exceptional, matchless cultural and historic story it has to tell its visitors in face-to-face meetings, is left untold.

However, after three days of diving in the mine filming for a TV show this past week, I have to say: I hope that changes soon.

The mine is a fantastic heritage resource. It gives us vivid insight into an important part of Newfoundland’s history and the daily lives of Bell Island’s working people. It also connects the region to what remains perhaps the most iconic conflict of the 20th Century.

Uniquely, Bell Island Mine focuses several major tourist attractions: firstly, the current mine museum and underground displays, the four ore carriers resting on the ocean floor a few hundred metres from shore, and of course the surrounding scenery: truly all remarkable experiences. Secondly, the portion of the mine workings now underwater have a very special appeal. The mine is filled with artifacts – machinery, tools, even the graffiti left my miners – and it fills its visitors, who still number less than 20, with a sense of wonder.

As a viable tourism product, certainly the potential buyers of structured and regulated physical access to the flooded Bell Island Mine are limited. Diving in an overhead environment (cavern, cave and mine diving), represents only a small percentage of the total scuba-diving market. But it is an influential population. Clearly, divers trained and equipped to dive in the Bell Island Mine will never flock to the area by the truckload. However, what the flooded mine on Bell Island has to offer, should be made available to those who wish to visit. The quality of the cultural and historic experience are simply too great not to be shared.


What follows is the text of an original article I wrote several years ago for TDI’s eNewsletter. Actually, the brief for the article was “The Benefits of International Dive Travel” but I used it as an excuse to promote diving in Newfoundland, the value of diving the Bell Island Iron-ore Mine, and the wrecks of four merchant ships sunk while loading with iron ore during WWII.

 

OK, before drilling into a few of the real benefits and surprises waiting for us when we decide on International Dive Travel, and certainly one of the most interesting associations with “foreign lands” in my diving career, we need to walk through a very quick geography lesson, followed by an equally brief history lesson!

Newfoundland is a big island off the east coast of North America. In fact, it is the most easterly point in the whole of North America and Signal Hill outside of Newfoundland’s capital St. John’s is where Marconi set-up his apparatus to receive the first radio signal sent skipping across the Atlantic from Cornwall, England in 1901. Like most of that part of the world, Newfoundland is rich in Celtic culture thanks to the influence of its early Irish-Ulster-Scot settlers, and the locals still sound more Irish than American. The waters surrounding the island are chilly (think icebergs drifting down from nearby Greenland… even in June!), are filled with the most amazing marine life — including many species of whale – and are home to four of my favorite shipwrecks anywhere in the world. We’ll get to those in a few moments.

When the Second World War erupted in Europe, Newfoundland — which today is a Canadian province — was part of Great Britain. Hence, when that country’s Prime Minister declared war on Nazi Germany in 1939, Newfoundland was automatically part of the Allied headcount. Canada followed close behind them, but it was not until a very closely fought referendum ten years later in 1949, that Newfoundland joined the Canadian Federation to become one of its ten provinces.

So, what about those four favored shipwrecks?

Just outside of the city of St. John’s, in the middle of Conception Bay, sits a small blob of land called Bell Island. During the years leading to the beginning of WWII. Bell Island had a very productive mine that exported iron ore to steel mills in several countries, including Germany. At the outbreak of war, steel mills, a little to the south of Newfoundland in Nova Scotia, accounted for about a third of Canada’s steel production vital to the British war effort. With shipments from the Bell Island Mine to German factories cut off because of the war, it was inevitable at some point that the Germans would attempt to interrupt production and throw a “spanner in the works” for the flow of steel to Great Britain. And interrupt they did.

On the night of September 4th, 1942, a German U-Boat sneaked into the anchorage at Wabana, Bell Island where ships loaded ore to be carried away to various “customers”. The next morning and within sight of the guns of the Bell Island Battery, the U-Boat sank two ore carriers moored at the loading docks: SS Saganaga and SS Lord Strathcona. Twenty-nine men were killed in the attack, all of the victims were seamen aboard the Saganaga.

The Battle of the Atlantic had suddenly come to within a few hundred metres of North America’s shoreline.

The strategic importance of the mines on Bell Island did not diminish of course, and just a couple of months after the first attack, a second U-Boat crept into Wabana and found several ore carriers at anchor.

The U-boat captain fired a torpedo at the 3000-ton Anna T. It missed and exploded ashore ripping into part of the loading dock and disturbing the sleep of many inhabitants on the island. In the next several minutes, two more torpedoes were fired at SS Rose Castle. Rose Castle sank, taking twenty-eight of her crew with her, five of whom were native Newfoundlanders. The Free French vessel PLM 27 was the second target. She sank almost as soon as a torpedo hit, taking twelve men to the bottom of the bay with her.

In the space of less than 15 minutes, two ships, several thousand tons of ore and 40 men had been lost. The U-boat escaped even though there were three allied navy escort vessels in the area.

The four Bell Island wrecks sit today at reasonable depths (the PLM 27 the shallowest at around 23 metres / 75 feet, the Rose Castle the deepest at 43 metres / 145 feet), and within a radius of a few minutes boat ride of each other and only a stone’s throw from land.

When I was first invited to dive the Bell Island wrecks, I must admit that Newfoundland seemed as remote to me as the dark side of the moon. Newfoundland was, at least in my ignorance, nothing but folk singers, remote fishing communities, moose, and wild, wild countryside battered by strong winds and salt spray off the North Atlantic. Through a number of visits over the following few years, I discovered that it was all of this and so much more.

The wrecks were one of the first surprises. Four shipwrecks each more interesting and more crammed with history than the last. After the first handful of dives, I christened the area Truk Lagoon North. Perhaps using a little poetic license but the things that seemed common to both areas were history, the awe inspiring evidence of the destructive power of torpedoes, the sadness of the lives lost, and the contrasting beauty of the creatures that had made the wrecks their home. Like many divers, I have a fascination with WWII casualties and the story all wrecks have to tell those with time enough to listen. Like the Japanese fleet in Truk, The Bell Island wrecks are master story-tellers.

One of the best pieces of luck I had on my first visit to Newfoundland and Bell Island was meeting Rick Stanley. Rick is a proud local who owns and operates Ocean Quest Resort, which was home-base for our group during our visits. Rick is a strong advocate for all things relating to Tourism for Newfoundland, and almost single-handedly has promoted responsible diving on the wrecks, as well as campaigning to have them designated as a war grave and a protected site.

During all my visits to the island, he and his staff, seem to go out of their way to make our group welcome and introduce us to local hospitality… including the infamous Screeching-In Ceremony.

Screeching In is when visitors (people from away, is how the locals refer to tourists) are made honorary Newfoundlanders. Space prohibits a blow-by-blow account of a true Screech In ceremony but proceedings include strong rum, eating local delicacies such as cod-tongue, hard-tack (ship’s biscuit) and dried capelin (a small smelt), singing, dancing, and “kissing the cod” which really does involve getting close and personal with a large dead Atlantic Cod (gadus morhua). Having survived being “Screeched In” during several trips, I can honestly say, it is one of the most bizarre and funniest things I’ve done during the course of several dozen dive  trips.

Partway through my third trip to dive the Bell Island Wrecks, Rick Stanley asked me if I would be interested in putting together a group of divers “Capable of exploring the Bell Island Mine.” Of course I said yes.

The mines were abandoned when it was no longer economically viable to operate them; but the closure was oddly abrupt.

The mines on Bell Island opened for commercial mining in late 19th century and were once the world’s largest submarine iron ore mine with passages occupying an area under the seabed of Conception Bay roughly five kilometers by five kilometers or approximately nine square miles in size.

The mine that Rick was interested in having surveyed and accessed — and that was the project’s main aim — had been closed since Christmas 1949. The story goes that the workers downed tools for the holiday and were never allowed back into the workings.

Rick and the Bell Island Historical Society were curious to have a team of divers explore the mine system — or as much of it as practical in the 12 days available — and look for evidence of cave-in, collapse, artifacts and other things that might interest a different type of visitor than the ones currently coming to the mine museum sitting at the old entrance to Mine Shaft Two.

The questions they wanted answers to where simple: can it be dived? Is it interesting enough to attract divers? Are conditions supportable for regular visitors? There were some side issues that needed to be addressed, but the hope was to open up a unique form of adventure tourism for the island and its economy.

With a background in Tourism Marketing, I was certainly curious enough to take Rick up on his offer, and set about building a team that would be able to pull things off. After a simple exploratory dive in July of 2006, we set a target date for the following January/February, and started planning.

Our goal was to investigate as much of the inundated mine as practical within the short time available. We knew the water would be cold, and because of the surface support needed, we also knew that our efforts would have to be focused on a time when normal tourist activity would not interfere; and that meant winter which also would be cold.

I was lucky to find the perfect group of men and women who were not daunted by the challenges that the season, the logistics, and the challenging dive site would present to us.

Newfoundland in the heart of winter is an interesting study. Stuck as it is with both feet in the Northern Atlantic, and its face weather-beaten by winds coming off the glaciers of Greenland or Labrador, it is not for the faint-hearted. Several of the team where Brits whose experience with a real Canadian winter had been limited to movies and books. They got to experience a true winter storm on arrival, and several of us had plane delays getting into St John’s airport. My plane was almost on the runway but the pilot aborted and we headed back to Halifax International with our tail between our legs and our hearts in our mouths.

But eventually, all 16 of us were together in the lounge at Ocean Quest Resort, sorting gear, knotting line, and pumping gas.

During the following two weeks, the team surveyed the mine looking for any evidence of cave-in or collapse in the mine shaft and laid permanent guidelines from the surface along the main shaft to a depth of approximately 50 metres. The seam of iron ore slopped at an angle of approximately ten degrees and continued many thousands of metres under the overlay of ocean floor below Conception Bay. In addition to the main line, four ‘jump lines’ were laid in side passages. The initial plan was to extend these side passages (roughly horizontal) approximately 300 metres east and west of the main shaft. Overall a total of 2km of line was laid in the mine.

The search for artifacts left behind when the mine was abandoned turned up mine equipment, personal effects such as lunch boxes, and we discovered graffiti, drawn by the miners using the soot from their carbide lamps. The system was mapped sufficiently to enable the conclusion that the mine would make a challenging diving destination for cave divers to explore.

Every overhead environment presents divers with a number of challenges well beyond the scope of recreational diving. As well as the obvious threats to the team’s well-being — gas management, navigation, light, depth and the cold — the health of one of our team played a role. On Sunday, February 4, Joe Steffen, well-known in the diving communities in both the Great Lakes and North Florida, suffered a massive embolism and died. Joe perished in a few metres of water just a couple of minutes from the surface operations. Ironically “Iron Man” had an undiagnosed problem with his lungs which did not show up during a medical he’d had before joining the team from his home in Ohio, and attempts to revive him at the dive site and the medical facility adjacent to the mine were unsuccessful.

We lost a great buddy, and Joe — a career police office — left behind a wife a young son, and a daughter, as well as many, many friends.

In consultations with the various sponsors — which included TDI, Fourth Element, Whites, the NACD, and Ocean Quest — as well as local authorities, the exploration of the Bell Island Mine continued and its success was dedicated to Joe’s memory.

The following year (2008), Joe’s widow, Jennifer, visited Bell Island for a memorial service which included two of the team (Mike Fowler and Steve Lewis) placing a memorial plaque and an urn containing Joe’s ashes in the main shaft of Bell Island Mine No. 2.

Tourists continue to visit the Mine and divers enjoy the four wrecks that sit above its vast network of passages, but underwater operations at the mine await further work.

The team consisted of: Rick Stanley, Debbie Stanley, David Sawatsky (diver and map-maker), Phil Short (diver, deep explorer), Ralph Hoskins (diver and record keeper), Vlada Dekina (diver and expedition photographer), Dave Clemmens, David Powell, Mark McGowan (dive safety officer), Stephen Phillips (diver), Aaron Bruce (diver), Mike Fowler (diver), Joe Steffen (diver), Steve Moore, Susan Copp, Steve Lewis (diver and expedition leader).

Setting Limits for cave diving: How much bailout gas should a CCR cave diver carry… and where?

Closed-Circuit Rebreathers (CCRs) are complex. Fewer moving parts than a Formula One car, and less mind-boggling than a Heath Robinson machine, but as mysterious and confusing as both to some folks.

Here’s one thing that certainly doesn’t help. When open-circuit scuba goes pear-shaped, the situation usually announces itself with gusto. Events such as a high-pressure seat failure, an o-ring giving up the ghost, a hose failing, or a manifold or burst-disk leaking, make themselves known immediately. Divers spend a huge percentage of the time during any technical training program, rehearsing a variety of valve shutdowns, regulator switches, and one or more options intended to deal with this type of failure, preserve what gas they can, and get their backsides out and to the surface with the least fuss possible.

By contrast, a CCR is not only quieter than open-circuit in normal operation, a whole category of failures arrive unannounced and quietly too. Certainly CCRs are still prone to many of the issues that plague their bubble-making dive buddies. Ruptured hoses, extruded orings, faulty handwheels, and free-flowing first stages are all possible. But in addition, there’s a whole category of sly, furtive malfunctions unique to closed-circuit diving; and each of these has the potential to cause real harm.

The default and simplest solution is to “bailout to open-circuit.” In other words, stop using the rebreather and switch to breathing from open-circuit gear to get back to the surface as rapidly as circumstances allow.

Advanced training for CCR divers puts strong emphasis on keeping the diver in CCR mode for as long as safety allows, and only bailing out as the primary option for scenarios like catastrophic loop failures or full floods, widely divergent oxygen cell readings, carbon-dioxide breakthrough, mechanical damage to primary components, etc. Cave CCR students, for example, are expected to consider all the options available to them in the event of a system failure – real or simulated. A full-cave CCR course is an exercise in complex navigation, and disaster scenario management. However, for the sake of overall safety, CCR cavers are also encouraged to bailout to open circuit if they have doubt about what needs fixing and how best to do so.

A useful phrase worth remembering is: THERE’S NO SHAME IN BAILING OUT!

Of course, as with most pieces of advice about diving, particularly cave diving, and more specifically about diving a CCR in a cave, there is a limitation. There’s no shame in bailing out… provided you have more gas then you need to get back to dryland in one piece.

And this begs the question: How much bailout gas is enough?

Calculating the answer to this is simply a question of using average depth (expressed in bar or ata), and multiplying that number by how much time it will take to get back to open water. In addition, one is advised to factor in some contingency volume for heightened gas consumption due to stress, hypercapnia, and so on. One suggestion is to work with a basic SAC rate of 30 litres / one cubic foot per minute. So using this baseline for a cave with an average depth of 20 metres / about 65 feet / 3 bar or ata, the bailout consumption rate would be 3 X 30 litres or 3 X 1 cubic feet per minute.

This calculation suggests an 80 cubic-foot cylinder (11 L charged to 200-210 bar)  would last approximately 25 minutes. Penetrations therefore would be no deeper than a 25 minute swim to the exit… where one might normally stage a small cylinder of decompression gas: usually pure oxygen.

Some divers use a slightly more conservative baseline, some slightly more aggressive. Some calculate a slightly lower consumption rate after the first 10 minutes on bailout, on the understanding that a diver will begin to regain control of his or her breathing after that time.

Another approach is the “one-hour rule.” Following this guideline, divers each plan to surface with one hour of all consumables in reserve, which includes lights, oxygen and diluent gases, scrubber, and bailout.

Whichever guideline one opts to use, the strong recommendation is to backup any seat-of-the-pants calculations by conducting simulated bailouts from various points in caves one dives regularly. These actual real-world data – with an added factor for stress – can then be inserted in calculations to arrive at a more accurate estimate.

Once one has an idea of how much bailout gas is enough, the next decision is how to carry it. Options include, about one’s person, shared among team members, drop-staged at various points in the cave.

The NSS-CDS, one of the original cave diving training agencies, suggests a dive team carries 1.5 times the volume of gas required to get a single diver out of the cave. Therefore, in the example above and a three-person team, each member would carry a fully charged 40-cubic foot bottle.

The logic behind “team bailout” is that there is, for the diver with a gas emergency, a greater level of conservatism than the acceptable norm for open-circuit cave divers. It does however demand that team stays in contact, swap tanks during their exit, and that only one unit has a problem that requires bailout.

Except in exceptional circumstances – with seasoned team members and when the basic bailout scenarios are inappropriate or impractical – I choose to carry on my person, enough gas to swim out of the cave on my own. Depending on the unit I am diving, I find that carrying two, 80-cubic foot sidemount cylinders is easy, comfortable, streamlined, and allows for plenty of time to exit from the vast majority of tourist cave dives. On occasion, for “smaller” dives or shallower profiles, I’ll strap on smaller aluminum tanks for bailout. If a dive requires a bailout volume approaching my normal carried volume, or a greater safety margin, I’ll drop stage bailout gas and/or work out a kind of hybrid personal-carry-team-dropped-stage strategy.

More than any other factor, one should be aware of the elevated gas consumption that typically follows an incident that demanded coming “off the loop” (bailing out). One also has to consider, especially if open-circuit diving is no longer part of your regular dive menu, typical consumption rates for a CCR diver using OC gear are often higher than expected. Something to do with the sudden shock of breathing cold, dry air I suspect.

In any event, remember to always have something appropriate to breathe, and plenty of it. You will never regret carrying more gas than you need.

Do some CCR training standards need to be revisited?

Lucky enough to have the option, and sometimes I use open-circuit technology because it better suits the environment and situation, but I think of myself as a rebreather diver.

Also, I count myself as lucky to be a rebreather instructor. I enjoy teaching something a little more complex, technically challenging, and arguably a wee bit more cerebral than basic open-water classes. However, I have issues with a couple of things that standards require me to incorporate into CCR training.

Let’s start with recommendations for the flavor of diluent in TDI’s first level of mixed gas training. (FYI: this is the program with a depth limit of 60 metres… that’s 200 feet American.)

The course standards require the diver’s diluent cylinder to contain 16 percent oxygen or more. At first blush this seems sensible. After all, a gas containing 16 percent or more oxygen can be breathed on the surface without ill effect… but only in open-circuit mode… and only in the majority of circumstances, not all.

Someone unfamiliar with rebreather diving, therefore (a trial juror for example), could be easily convinced that even if the rebreather was unable to add supplemental oxygen to bring the partial pressure up to a healthier range – either because of a malfunctioning oxygen solenoid or depleted oxygen supply cylinder – the diver would be “OK” to surface and get out of the water. A 16 percent oxygen mix would be, then, a good choice to breathe in these circumstances.

However, it is not. Few CCR instructors promote this option. Most – me included – would promote coming off the loop and breathing bailout gas (decompression bailout gas for example), long before surfacing.

In essence, the fact that the diluent is breathable on the surface in very limited and sub-optimal circumstances has little bearing on risk management.

One might argue that such a gas is potentially dangerous. And the truth is that breathing a trimix diluent, any diluent even air, on a malfunctioning unit or with an empty oxygen supply cylinder on the surface or close to the surface on a rebreather is a poor choice. It would be a crap shoot anyplace shallower than say 21 metres (about 70 feet American). In my opinion, the risk of hypoxia – and other complications – is too great at that depth or shallower. Best option is to bailout to open-circuit deco mix. Easier. More likely to have a happy ending.

So, would I like to have standards suggest the oxygen content of the diluent bottle be increased? No, just the opposite.

The issue has nothing to do with what can be breathed on the surface. This is a red-herring in my opinion. With a functioning unit, the oxygen content of the gas within the diver’s breathing loop at the surface (the oxygen set-point) will be maintained at something like the equivalent of breathing EAN70. If the unit cannot do that, the diver is best advised to bailout to open-circuit gas… OFF-BOARD OPEN CIRCUIT NOT DILUENT.

So, the diluent on the surface issue is not an issue at all. What is an issue is what happens at depth.

The procedure of emptying the contents of a rebreather’s breathing loop and replacing it with diluent, is called, unsurprisingly, a diluent flush. It serves a couple of functions, each with a specific benefit.

Let’s look at number one function of a diluent flush. Doing so, replaces the gas being breathed with a known entity with a predictable oxygen partial pressure. That oxygen pressure is derived by multiplying the fraction of oxygen in the diluent by the ambient pressure expressed in bar or ata. So for air diluent at 30 metres the solution is approximately 0.20 X 4, which equals 0.8. And that’s what you’d be breathing after a complete flush on air, at 30 metres (100 feet). And, importantly, that is what you’d expect the readout on the unit’s PPO2 display to show you.

Reassuring when this happens. Even more so because you can then watch each oxygen sensor’s behavior as the unit starts to add oxygen to bring the loop gas up to its intended set-point (let’s say for example’s sake, an oxygen partial pressure of 1.3 bar). The speed at which the sensors respond and refresh a gradually rising PO2, and the uniformity of their display can indicate everything is functioning as it should… or that there are problems.

Now, let’s imagine we are diving at 60 metres using a diluent containing 16 percent oxygen. The ambient pressure at 60 metres is 7 bar/ata, therefore a quick diluent flush will return a partial pressure of approximately 7 X 0.16, which is 1.1 – 1.2 bar. If you were running a set-point of 1.3 bar or 1.2 bar (both are possible and common choices), a diluent flush would tell you bugger all. A diluent flush would not appreciably change the oxygen partial pressure.

In my opinion, diving to 60 metres on a diluent containing 16 percent oxygen is not the best option… actually, it’s a rather poor option, and one I am reluctant to recommend. I believe doing so takes away a valuable, vital real-time test of oxygen cell function.

Here’s my point. While 16 percent oxygen may support life when breathed open-circuit on the surface, the likelihood of a CCR diver opting to do so, is remote… perhaps a very last resort… if that. Whereas executing a diluent-flush at depth to check on oxygen cell behavior is something one might do several times during a dive.

I’m all for managing risk, and having your backside covered should the Rottweilers hit the fan, but I don’t believe TDI’s suggestion of the “correct” diluent for 60-metres dives does so… it is simply too oxygen rich. Why not suggest a 10/50 diluent on all CCR dives to 80 metres and above? It’s easy to mix and is the default diluent gas sold to divers in many, many of the dive shops I use.

At 60 metres (7 atmospheres, 200 feet), a partial diluent flush with a 10/50 returns readings of around 0.7 bar, which gives one the widest scope possible for watching oxygen cell behavior.

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The “weighting test:” are technical divers absolved for some reason I don’t know about?

When you first learned to dive, I’d bet dollars to doughnuts that your instructor explained a simple trick to help you check how much lead you should carry. It went something like this:

  • The diver enters water (at least 3-4 metres deep) with gear in place and a regulator in her mouth, with her cylinder almost empty (SPG reading perhaps 50 bar/500 psi)
  • She inhales and holds a full breath then vents all the air from her buoyancy device.
  • She hangs motionless… Quiet hands and feet
  • If correctly weighted, after 30 seconds or so, she will settle in the water and float at eye level, half her mask window below the water, half above
  • She exhales and slowly sinks

What is not commonly taught is that this test can be completed with a full tank also. The only difference being that the diver should add enough ballast after the test to compensate for the weight of gas that she will use during the dive… the aptly named buoyancy shift… otherwise she will be too “floaty” to hold a safety stop at the end of her dive.

Your first instructor may also have explained exactly why carrying too much lead is a recipe for a miserable dive. Achieving good trim, buoyancy control, presenting a streamlined angle of attack to the water, and in-water comfort can be difficult for new divers but more so when he or she is over-weighted. Hence the value of doing a weighting test: it is definitely time and effort well spent.

Of course, an alarming percentage of divers all but ignore the lessons taught by the test and dive with “a little extra lead just to be safe.” God only knows what that’s supposed to mean, but it happens too often.

Now just in case you consider yourself a technical diver and are reading this thinking: “Bloody sport divers… always getting it wrong;” I believe that the worst offenders in the over-weighting challenge are technical divers. That’s right buddy, you and me.

The Balanced System Misunderstanding
The term “balanced system” actually describes three important aspects of gear selection and configuration. The first is the outcome of the balancing act between buoyancy and gravity, and whether the diver and the gear she takes into the water floats or sinks when it’s all put together. (Simplified to does it float or does it sink.) Secondly, the weight of ballast that could be ditched should the Rottweilers hit the fan and the diver has to swim for the surface without a primary buoyancy aid. (For a sport diver this ditchable weight is usually his/her weight belt; and for a technical diver, it might be stage bottles etc.). Thirdly, where the ballast should be located or carried since this will affect the diver’s trim and issues with the angle of attack as he or she moves through the water.

For a technical diver, understanding and addressing all three is necessary — just as it is with his or her sport-diver buddy — but the nuances of all three issues are more complex to calculate and more finicky to arrange for anyone engaged in tech diving profiles.

You may have read before in various onLine postings and perhaps textbooks that “a balanced system is one that a diver should be able to swim to the surface even with a failed [primary buoyancy cell].”

The ability to get themselves and as much of their life-support system back to the surface is certainly something technical divers should strive to achieve, but without any actually thought, calculations or in-water testing, it really cannot be assumed. Many do.

For example, the buoyancy characteristics of most sets of traditional North Florida Cave Rigs (steel backplate-mounted and manifolded doubles) means most would have a hard time to qualify as balanced at the beginning of a dive when fully-charged with gas.

For many technical divers, their backmounted doubles (and the gas they contain) constitute the vast bulk of the ballast they carry. So in effect, they often carry very, very little ditchable weight… if any. If they are over-weighted, they have nothing to ditch. In an emergency, swimming a set of steel doubles up to a safety stop and holding position in the water column for even a few minutes would be close to impossible and certainly stressful for these people.

Luckily, primary buoyancy cell failures are rare, but even so, divers who opt for steel doubles need to be aware of the potential challenges their kit presents them with… you can’t take off one tank and swim the other one to the surface when wearing twin cylinders!

Sidemount users have things slightly easier because they can unclip one primary bottle, dump it, and surface while breathing from the second. But their systems present challenges too. Rebreather divers also have a special balanced rig paradox to sort out if they happen to have a “dramatic moment” at depth.

Weight Changes During Your Dive
As a diver, especially a technical diver or one who aspires to become one, and contrary to the assumptions made by the Ideal Gas Law, we need to understand that gas has mass. For non-scientific applications this means gas weighs something and as it is consumed during a dive, the drop in gas weight is what contributes to buoyancy shift.

I don’t usually speak American Standard Units, but you might and if you do, you should take note. A cubic foot of air weighs approximately 0.0807 pounds. Perhaps more useful is that 13 cubic feet of air equals about one pound. Therefore, a diver carrying a couple of 130 cubic-foot steel cylinders, who has consumed just half of a full air fill during her dive, will be approximately 10 pounds lighter than when she started!

For the rest of the world, one thousand litres of air – assuming standard content, pressure, and a temperature of 0 degrees – will weigh around 1.29 kilos… slightly less at higher temperatures. So, a diver starting her dive wearing two 10-litre cylinders charged to 230 bar is carrying a little less than six kilos of gas with her!

Another thing that may affect weighting is the type of thermal protection being worn. For instance wetsuits compress and the lift they provide will decrease as depth increases. Drysuits and what’s inside them providing insulation, also compress at depth and provide less lift.

So… Let’s Determine How Much Ballast
The first step of the weighting test for a technical diver is similar to the one used by sport divers.

Work in a spot where there is sufficient depth to submerge but not a wall dropping to trimix depths. The six-meter / 20 –foot platform at your local quarry should be perfect. This is your test zone.

With minimal gas in your cylinders (a little less than one-third of their working, rated volume), no gas in your buoyancy cell, just enough gas in your suit to be comfortable (assuming you are wearing a drysuit), check to make sure you are able to maintain eye-level surface float with your lungs full. Exhale, and you should begin to sink slowly. This is the balance between buoyancy and gravity that you should aim for.

If you cannot sink, your rig is under-weighted. If you cannot float without adding gas to your buoyancy cell or suit, it is over-weighted.

Step two is a little more complicated.

Below where you completed step one, perhaps on that platform at six metres / 20 feet, have a collection of small lead weights that equal the weight of the gas that is “missing” from the cylinders you wore in step one. Use a handful of small weights… one kilo or less each. Have enough to make up the weight of a full fill and perhaps a little more. Use the 1000 litres weighs one and a quarter kilos, 13 cubic feet is one pound guideline.

Now descend to the platform, check your gas volume… now’s not the time to run out of something to breathe. Pick up all the weights, put them in a pouch, in a pocket, in a mesh bag, whichever works for you, and kick for the surface. Remember, no gas in the buoyancy cell. You CAN put a little in your suit, but don’t overdo it. The test is to calculate a balanced rig not to cheat.

This additional weight simulates your in-water weight at the beginning of a dive. If you can make it back to the surface, great. If not, relax, sink back to the platform and take out one small weight at a time until you CAN make it to the surface. Take note of by how much you were over-weighted when you initially tried to make it to the surface. Note how much lead you dropped before you were able to swim up.

You might say that whatever weight that is, represents how many litres or cubic feet you would have to breathe or dump to get back to the surface should something bad happen at depth. Not a terrific situation.

Frankly, being over-weighted by ANY amount has the potential to be life-ending. It’s certainly not smart. You may need to adjust your kit configuration. Use an aluminum rather than a steel backplate, get smaller cylindersor ones with different buoyancy characteristics.

Cut out as much excess non-ditchable ballast as you can. If you need lead to achieve balance in step one of the weighting test, make sure it can be ditched. I see a lot of divers adding V-Weights between their backplates and tanks… you do the math.

Stages and Decompression Bottles
When you carry out steps one and two of the weighting test outlined above, don’t wear stages or other bottles. These are ditchable and can be dumped in an emergency when a dive is first starting and your rig is at its heaviest. However, DO consider that aluminum stages and deco bottles (the type preferred by the majority of technical divers), have strange buoyancy characteristics and may float when empty or near empty. Factor this into any considerations for holding a safety stop.

In other words, should you have a problem with your buoyancy cell and are too heavy, hand off any negative bottles to your buddy. If they are empty, too positive, and you believe they may prevent you holding a stop at the end of your dive, you can dump them because they will probably float to the surface.

Rebreathers and Bailout Bottles
Rebreathers divers use very little gas during a diveusually just a couple of hundred litres, perhaps 10 cubic feet… therefore, their gear’s buoyancy shift is minimal. However, they carry bailout bottles. These may stay untapped for months. Only issue might be that on the one dive where they have to be used, the diver will ascend with less weight than “usual,” since they’ve been breathing open-circuit since they came off the loop. Because of this, the suggestion is to do a weighting check simulating a safety stop with one or two spend bailout bottles strapped to you.

Conclusion
Making the effort to get your weighting will increase your comfort and you will be in a much better position to handle emergencies, like wing failures and other problems. Cutting excess weight will make it easier for you to control your buoyancy, and you will not be wasting as much gas continually filling and dumping your buoyancy cell during the dive.

You may also derive some benefit from buying a digital fish scale. You can use it to measure the in-water weight of various accessories such as stage bottles, cameras, lights, reels and the like. Simply zero out the scale, lower the accessory into the water, hook the digital scale to it and it will display its weight. Cool too if you want to calculate an object’s volume!!

Remember also that you need recalculate your weighting when you change something in your configuration like tanks, primary lights, regs or drysuit underwear.

Have fun and dive properly weighted.

Flying after diving… what are the guidelines?

Here’s a somewhat common scenario… perhaps one you have experienced yourself; or thought about at least.

Anyhow, here it is. You and your buddy are on a dive vacation someplace that requires airline travel… bummer, right!? Pack light. Hope the TSA doesn’t break anything on your way out. Hope customs at the destination doesn’t fuss over anything on the way in.

However, all those issues aside, every other piece of the planning puzzle is falling into place just fine except for one small issue. The flight home is scheduled wheels-up at O-Dark-Hundred in the morning, and there is an opportunity to dive something really, really cool the previous afternoon… late in the afternoon. The question is: Can you do that dive without getting bent like a pretzel on the flight home less than 12 hours later?

The whole issue of Pre-flight Surface Interval (PFSI) is a contentious one. The old-school guidelines were wait 24 hours after diving before jumping on a commercial flight. But that recommendation has been revisited in more recent studies and the PFSI shortened; with suggestions that various other factors such as breathing nitrox, the length of safety stops, gas breathed during safety stops, and the duration and depth of dive, can all influence by just how much the PFSI can be shortened.

A quick straw-poll of my dive buddies tells me that the definitive answer is a moving target. There is little agreement.

What we can take as read is that flying after diving has a strong potential to apply extra decompression stress on a diver and increases their risks of decompression sickness. There seems to be a direct relationship between the risk dropping and the amount of time spent out of the water increases allowing excess inert gas to be eliminated normally and harmlessly through the lungs. Some trials have estimated the PFSI necessary for a low DCS risk (read acceptable number of incidents of DCS) after relatively long single or repetitive no-decompression dive profiles sits between 11 and 16 hours.

The PFSI for dives requiring staged decompression stops, was around 22 hours. At first blush then, a 24-hour break after diving would seem in most sport-diving cases to be very conservative. But then again, what worked in a dry chamber on a couple of hundred test subjects, may not apply to the average dive tourist coming home from a week in paradise where the diving was punctuated with rum, grilled fish and late-night romps on the beach. Equally, it also may not apply to an informed technical diver who pads her/his decompression stops with extra time, and breathes pure oxygen for long periods during that PFSI!

Well worth the download and reading time is: The Influence of bottom time on preflight surface intervals before flying after diving, published by Undersea Hyperb Med. And authored by Vann RD, Pollock NW, Freiberger JJ, Natoli MJ, DeNoble PJ, Pieper CF. (2007). It is available from the ultimate diver’s research tool: http://archive.rubicon-foundation.org/xmlui/handle/123456789/7343.

The study’s conclusion suggests “that bottom time, repetitive diving, and a decompression stop may significantly influence the pre-flight surface intervals required for low DCS risk. Moreover, it highlighted the need for additional human trials to resolve the effects of exercise and immersion on DCS risk during flying after diving. Such information might assist in the calibration of dry, resting trials for the effects of immersion and exercise which would be useful as dry, resting trials are less expensive and faster to conduct because more subjects can be exposed per chamber dive. This might be of aid for improving the accuracy of existing flying after diving guidelines.”

Significant in that conclusion is the call for additional human trials to resolve the effects of exercise and immersion on DCS risk when flying after diving.

I volunteer.

However, I would be far from an average test subject since something seems to put me outside the bell-curve for DCS risk. For example, my experience with PFSI is far from what’s generally acceptable and my practices at times have been foolhardy. Furthermore, I fall outside the age category that most studies could ethically accept in any trial… but all that aside, I would love to be a guinea pig.

 

Normalization of Deviance

Many divers, probably most divers, accept that diving can be truly dangerous. Of course, from time-to-time you’ll probably bump into someone who tells you and, most importantly, themselves that the risks associated with diving apply only to other people and not to them, but the majority of us are supremely aware that the Rottweilers can hit the fan on any dive, at any time, and for any number of different reasons. So it seems odd that there is so little mention in diving books and student manuals of the one “behavioral fault” common to the majority of dive fatalities.

Every year, the Diver’s Alert Network releases its report on diving incidents, injuries and fatalities. This is, in my opinion, the most valuable piece of data collection and analysis done by any organization within the dive community. It makes for compelling, but somewhat depressing reading. For example, in its 2010 report, it shares with us that there were 144 scuba-related deaths reported world-wide.

If we were to summarize the factors that contribute to dive fatalities, at least those in DAN’s report, we’d find four categories.

  1. Poor health (divers being really out of shape, on meds, ignoring common sense and diving with existing ailments or injuries).
  2. Procedural errors (things like not analyzing breathing gas, diving a rebreather with dodgy oxygen cells, running out of gas, etc.).
  3. Issues with the environment (getting into trouble because of changing conditions, like currents, visibility and the like).
  4. Problems with equipment (particularly serious in the world of rebreathers, but also including situations where a piece of kit goes pear-shaped and the diver freaks out and panics).

However, it seems to me that there is a fifth to add to that list, and its influence seeps into and significantly colors each of the other four. The Normalization of Deviance describes a dangerous facet of human nature. It goes something like this: We do something that does not follow the accepted (and acceptable) rules or guidelines – for example, we skip certain steps in a “standard” procedure because it saves time. The trouble stems from the unfortunate fact that we get away with taking the shortcut. Then, believing it’s safe to make the same safety shortcut next time around, we do the same thing… we ignore safe practice, established safe practice. In the absence of things going totally pear-shaped, our deviation from normal practice and safe procedure becomes a new acceptable norm.

The term Normalization of Deviance is from Diane Vaughan’s book on the Space Shuttle disaster, In that book, The Challenger Launch Decision, Vaughan, a professor in Columbia University’s Department of Sociology, points out that the component failure that contributed to the loss of the Space Shuttle, and the deaths of seven crew members on January 28, 1986, was predicted before the launch. The risks were known and documented!

She explains that normalization of deviance within NASA and Morton-Thiokol (the company that manufactured the solid rocket boosters (SRBs) used to propel the shuttle into space), allowed a recognized design flaw to be ignored. She writes: “As [NASA and Morton-Thiokol] recurrently observed the problem with no consequence they got to the point that flying with the flaw was normal and acceptable” In essence, flight plans made no allowances for a known issue with the SRBs.

This deviation from best practice resulted in what Vaughan termed a: Predictable Surprise. Eventually, luck ran out, the component failed and the shuttle disintegrated 73 seconds after launch killing five astronauts, two payload specialists, and grounding NASA’s shuttle program for almost three years.

Normalization of deviance – and the predictable surprises that follow – are part of that catch-all phenomenon too often observed during the accident analysis that follows failure of any high-stakes, high-risk endeavor. We call that phenomenon: Human Error.

Certainly normalization of deviance shows its ugly face in diving. Often. A classic example is the double deaths of Darrin Spivey, 35, and Dillon Sanchez, 15 on Christmas Day 2013. Spivey, certified only as an open-water diver, took Sanchez, his son, who held no recognized dive training or certification at any level, to try out new equipment, Sanchez had received as a Christmas present. For that tryout dive, they visited the Eagles Nest cave system, which is situated within the boundaries of Chassahowitzka Wildlife Management Area, Florida.

Spivey and possibly Sanchez were aware that they had no business attempting such a highly technical cave dive without specific training in cave, decompression, and trimix. The Eagles Nest, also called Lost Sink, is known justifiably as a very advanced, highly technical dive. There is even a huge sign at the water’s edge proclaiming such.

And it’s no secret that such an advanced deep dive demands respect, and training, experience and planning. Especially since the top of the debris cone directly below the system’s rather tight vertical entrance is deeper than the maximum sport diving limit. Anyone wandering in there by accident, would very soon realize the magnitude of their mistake and get the hell out of dodge… well, most would.

But Spivey and Sanchez had broken the rules before and gotten away with it. The pair had, according to records and the later testimony of family and friends, dived several North Florida caves including the Nest, and walked away Scot free. Their luck held.

Like NASA and Morton-Thiokol, Spivey and Sanchez had normalized their deviant behavior, and until Christmas Day 2013, everything was fine. Their predicable surprise was that both father and son drowned.

We all take shortcuts… Certainly I have, and I am sure you have too. If we have done so with dive safety, we’ve been lucky and have gotten away with it… up until this point at any rate.

Because of the regularity of dive fatalities and the metaphorical wake-up whack on the side of the head that these accidents can deliver, stopping the normalization deviance should be a breeze for divers. It should be simple for us to stop taking safety shortcuts. But I don’t think the dive community as a whole is particularly vigilant on that score.

Dr. Petar Denoble, DAN’s research director, writes: “While each accident may be different and some of them occur in an instant, most accidents can be represented as a chain of multiple events that lead to deadly outcome. Removing any link from that chain may change the outcome.”

I’ll put myself out on a limb here and say that if the dive community, especially dive leaders such as training agencies, instructors and other dive pros, could put greater emphasis on the pratfalls and consequences associated with the normalization of deviance, it might help to lessen the unfortunate tendency of some divers to depart from established best practices… We would in essence, be removing a link that shows itself in many chains of error. And we might see diving fatalities shrink: perhaps not to nothing, but at least shrink a little.

We will never change human nature, and never eliminate human error; but we can help to create a culture of responsibility based on a realistic review of what kills divers.

I wanna make a case for unsweetened tea

If I first tell you that I’m an expat Brit, it will probably come as no surprise if I also share with you that I enjoy a cup of tea. A few shots of strong espresso in a bowl of hot milk is my morning drink, but tea is on the menu for most of the rest of the day. Perhaps less easy to fit into the ethnic stereotyping is the way I prefer my tea made. That preference is not hot with milk and sugar, but black with lemon, cold and unsweetened. And if we want to assume another level of stereotyping, you might ask yourself how I developed a taste for a drink that is a favorite in the Southern States but difficult to find most any place else, especially where I live in rural Canada.

By the way, the answer to the question above would be scuba diving. I like to drink unsweet tea anytime I can lay hands on it, but in particular I like to drink it when I am diving. Now I should also explain that I drink a lot of water when diving or otherwise. On a normal day, my water intake is around two to two and a half litres. When I am diving, I throw down at least that much. However, I also like to drink tea… probably a litre or more of it given the chance. My guess is that I “caught” the habit hanging out in North Florida’s Cave Country.

Now just in case you are reading this and saying quietly to yourself: “Guy’s an idiot. Tea is a serious diuretic and divers should steer away from it,” give me a couple more minutes.

And by the way, if you ARE thinking that, you’re not alone. I was recently on a dive boat (an excellent live-aboard working out of the Florida Keys). Always open for suggestions and customer feedback, one of the owners asked what I would change about their operations. I suggested their soda gun have a button for unsweetened tea added. She looked at me with a smile and explained that tea being “the most powerful diuretic known” I would not be seeing it on the menu for her divers anytime soon.

I resisted the temptation to argue. For example, I resisted the temptation to point out the boat’s soda offerings included: cola, and root beer; both of which have serious dietary side-effects from ingredients not to be found in tea. I also chose to not point out that there was a huge canteen of coffee on the galley counter below decks… surely if tea is diuretic, that must be too. Right? And thankfully, and most of all, I resisted the temptation to cry: “Bullshit.” Because bullshit it is.

Here are some facts about tea.

Tea is, at worst, mildly diuretic; with the emphasis on mildly. While you may poo-poo the veracity and question the bias of any study I care to cite here, data – and not some bullshit hearsay from a dubiously researched diving manual – indicates that everyday consumption of tea (hot or otherwise) does not produce a negative diuretic effect unless the amount of tea consumed at one sitting contains more than 300mg of caffeine. Since the average cuppa contains around 50mg, you’d have to drink about 1.5 litres of tea in one sitting to ingest this level of caffeine. That, my friends, would take some serious guzzling.

It may be worth noting that the British Dietetic Association has suggested tea can be used to supplement normal water consumption! Nothing there about tea being counter-indicated for good hydration… the opposite in fact. The BDA report went on to state that “the style of tea and coffee and the amounts we drink in the UK are unlikely to have a negative effect [on hydration]”. I think we are safe to apply the same logic anywhere else in the world.

A clinical study published by the British Tea Advisory Panel (admittedly a potentially biased source) stated that a cup of tea can be just as good as a glass of water at keeping your body hydrated. It explained that four to eight cups of tea consumed throughout the day, is thirst quenching “without any diuretic side-effects.” Now, I am willing to squint a little at one or two of those assumptions without adding some provisos but it’s interesting nevertheless.

In addition, the Harvard School of Public Health rates tea as one of the healthiest beverages. Tea contains essential nutrients that are being studied for their value in possibly preventing heart disease and diabetes. For instance, brewed tea is rich in free-radical fighting antioxidants.

Unsweetened ice tea is also naturally low in calories. A 16-ounce glass of unsweetened ice tea (that’s a little less than half a litre) will deliver about three calories. The same volume of cola contains about 180 calories all of which come from sugar.

Now you are free to drink whatever you want. And if I am on your boat, I will follow your rules and allow you to live by whatever odd dietary foibles you may have. But, please get something straight, unsweetened iced tea is NOT a serious diuretic and in fact may encourage divers who have an issue drinking a healthy dose of water to actually better hydrate.

Thanks for your time!

Anyone for a cuppa?

SMS75 from Hollis…

Thoughts about the latest sidemount harness from the folks who brought us the SMS100 and SMS50

 

Last November I had an opportunity to dive the prototype of a new sidemount harness being developed by Hollis. Already a SMS100 and SMS50 user, I was interested to see what the company’s “mid-range” design could do that the 100 and 50 could not.

That November introduction involved diving the Hollis rig at Jackson Blue Spring in Florida. I enjoyed diving it and immediately phoned my contacts at Hollis. I explained the 75 was almost exactly what I wanted from a sidemount harness. I wanted one to dive in a variety of conditions to test if my original assessment was correct. I had to wait a while. Quite a while and when my first shipment of SMS75s arrived from Hollis a couple of weeks ago, I was extremely happy to finally have units in-hand.

Not only did I had pre-orders from students who were signed up for sidemount courses, I was even more excited to get my personal unit in the water for proper testing outside a cave environment to see how it fared in colder water and lumpier surface conditions.

FIRST IMPRESSIONS
I’ve never been disappointed with kit from Hollis. My experience with the company’s wings, fins, instruments, DSMBs, reels and so on has been really positive. It may cost a little more to design and produce gear that’s going to last ages, but I hate having things break because of cheap components and crappy quality assurance controls. I cannot say price is never an issue, but I am willing to fork out a bit more cash in the hope of avoiding the sort of disappointment that inevitably follows using shoddy kit of any sort.

With that said, right out of the box, the SMS75 is impressive. As with the SMS100 and its tiny travel cousin the SMS50, the 75 looks like professional-grade gear, and in a side-by-side comparison with other units in my personal dive locker, the Hollis stands out. If you know power tools, I think a fair comparison is comparing a heavy-duty DeWalt or Milwaukee cordless drill with a $29.99 special from a no-name manufacturer only doing business on eBay. Anyhow, built from rugged 1000D Cordura, the SMS75 looks tough enough to take a beating, and the finishing is excellent… no hanging threads, gaping or marginal seams or dodgy sewing.

As well as the build quality, the SMS75 has several design features that result from outside-the-box thinking. These deliver benefits that are easy to appreciate and that make rigging simply and comfortable with the least possible fuss.

THE HARNESS
The traditional habit of taking the shoulder harness and anchoring it behind a diver’s hip is a throwback to the design restraints of the North Florida Cave Diver’s backplate and wing setup. When faced with the challenge of taming a set of double steel back-mounted cylinders, legend has it that Greg Flannigan and Bill Main solved the issue with a continuous length of two-inch webbing and a purloined Florida Department of Transportation road sign. Fixing the over-the-shoulder harness was easily done by threading it through the backplate and almost every backplate manufacturer almost thirty years later, uses the same method. Most sidemount manufactures – including Hollis with their SMS100 and 50 – follow suit. Trouble is that this routing for a harness while reasonably stable, is not the most comfortable nor does it make things easy when trying to doff and don kit.

With input from a couple of Hollis Ambassadors, Nick Hollis, himself a sidemount diver, Edd Sorenson and other hard-core cave divers, the shoulder harness on the SMS75 is different. It attaches to the waistband away from the diver’s lower back and close to his or her side or front effectively creating in combo with the unit’s crotch strap, a stable three-point anchor system.

Not having two-inch webbing biting into your armpits may take some divers a few tries to get used to but for me at least, it felt immediately more comfortable. Once adjusted it also felt more stable, but there is a temptation to over tighten the shoulder straps which pulls the waistband out of anything approaching alignment. The trick is to get it snug and then let gravity and the crotch strap do its work.

THE BUOYANCY CELL
Another obvious innovation is the trapezoidal-shaped buoyancy cell on the SMS75. Unlike a traditional wing, it puts most lift around the diver’s hips and none at all on the shoulders. The traditional wing used in tandem with an aluminum or steel backplate spreads buoyant lift more or less equally between the shoulders and hips. For the typical sidemount diver who wishes to attain a horizontal trim, a traditional wing, or an integrated buoyancy cell delivering any appreciable lift at the shoulders will create a challenge: this type of cell tends to float the diver in a heads-up orientation.

The benefit is that right from the first couple of seconds in the water, a diver using the SMS75 trims out at or close to horizontal. While some other sidemount systems often require modifications or trim-weights on the diver’s shoulders, I’ve found that small changes in the tank cam bands is all the adjustment necessary to get a diver “squared away.”

BUNGEES
I’ve long been a fan of the more traditional loop bungee (AKA Armadillo or Old School bungee) over the straight bungee or ring bungee. I find it keeps the neck of the primary cylinders under control and helps to set up their orientation where it’s supposed to be (at the diver’s side) and at an angle that is correct (parallel to the diver’s lateral line). The SMS75 ships with loop bungees, and this once again saves time getting the system set up ready for diving.

LOCATION OF CONTROLS
One last innovation. The SMS75 features ‘reversed inflator/dump:’ the OPV/Dump is located on the top of the unit behind the diver’s head while the inflator is protected and tucked away on the diver’s left hip with the working end of the hose and its inflation valve located on the left breast and held in place by small-diameter shock chord.

For those used to finding the draw string for the dump close to their hip – or a little lower – it will take a few dives to unlearn the old muscle memory and relearn a new one… but in my opinion, the ubiquitous plastic elbow fitting is the weak spot of almost all buoyancy devices. Having it tucked away and out of the way is worth a few minutes learning a “new trick.”

DIVING THE SMS75
In two words: It’s magic.

There are several good sidemount harnesses on the market. They each have pros and cons, and frankly I have no issues diving many of them because they work and are fun to dive. However, I teach sidemount and one of the toughest “asks” of any instructor is getting the student and his or her harness to fit together like a hand and glove. You can get there with almost any unit from a reputable manufacturer, but it takes some work. In the most extreme cases, that work involves scissors, a grommet punch, and lots of cable-ties or an industrial sewing machine. In the easiest, there is always some modifications to be done.

The SMS75 is an exception. This past weekend, I worked with three divers wearing SMS75s and had them all just about done inside of an hour of surface and in-water time.

WHAT I WOULD CHANGE
Hey, I am a sidemount diver, so of course there are two things I would change, even on the SMS75. I’d like the double ring clip attached to the center of the butt plate to have slightly larger clip-off points, and I’d also like a second set of door handles either side of the butt plate… but neither is going to stop me from diving it.

CONCLUSIONS
The marketing message from Hollis tells us:

“The SMS75 is an evolution from years of sidemount development, which started with the SMS100. A product that has been copied, modified and a benchmark for technical sidemount for years. Even more popular has been the lightweight SMS50 line. These two have taken sidemount mainstream and the building blocks this new harness. While it will cater more to hard-core cave divers, SMS75 was created to handle all environments.”

All good stuff, understandable, and not full of bullshit. Most of the OC diving I do these days is in overhead environments – caves or wrecks – and the choice to dive this style of kit configuration, after more than 18 years diving traditional backmounted doubles, was based on both lifestyle AND mission specific criteria. Sidemount is not a panacea. Nothing is. It is simply an extremely flexible and useful tool that works for many different types of diving.

I think it’s fair to say that with the SMS100 and the SMS50, Hollis helped to convert many divers to “going sidemount.” Hollis was a relative late-comer to sidemount diving, but they listened to community feedback and in just a few years, have become one of the manufactures who are front and center in the sidemount market. With the SMS75, its divability out of the box, the ease with which it can be configured, and the range of diving that I feel it’s suited for, Hollis definitely has a winner.

Important to note that the SMS75 is not revolutionary. It is not going to turn a bad diver into Superman or Wonder Woman and it does not have a special switch that will suddenly fix an OOA problem. However, it is a fine piece of kit. Well designed, balanced, well-made, easy to use, and reasonably priced.

And while it’s unlikely to bring peace to the Middle East, it certainly has the ability to bring sidemount diving within the grasp of a lot more recreational and technical divers. And if you haven’t tried it, give it a shot… you might like it.

 

A FEW DETAILS
As an aside, the SMS75 is rated for 40 pounds of lift (enough to float about 18 kilos). The smaller SMS50 is rated at 23 and the SMS100 is credited with a touch more than 50 pounds lift. The SMS75 is available in three sizes: SM/MD, LG/XL and XXL and the system weighs seven pounds. It also ships with two cam bands, SS bolt snaps and enough equipment line to rig two primary cylinders. Suggested retail is $695US.

 

It’s not always deep and scary…

The same probably happens to you too. I’ll be at a dive show or some dive-related event and people will ask me about memorable dives. I think what they expect to hear are the “Boy’s Own Paper” adventure stories about a bunch of us stacked up like cordwood in a very small cave entrance to decompress; or drifting in the Gulf Stream at 60 metres being tailed by sharks and waiting for a shipwreck to appear out of the gloom. And normally, that’s what they get. However, some memorable dives are simply not framed in anything like such an exotic setting. Some dives are memorable simply because they pack an unexpected surprise… or they excite someone else… or both.

This past weekend I had the opportunity to make a dive in Lake Rosseau at the site of the long-defunct Royal Muskoka Hotel. Lake Rosseau is one of the three big lakes in Muskoka about 18 kilometers long and eight wide. The southern end of the lake is about 200 kilometers north of Toronto and for more than 150 years, along with the rest of Muskoka, has been a vacation spot and cottage country for folks from the city… and much further afield.

The Royal Muskoka Hotel was opened at the turn of the 20th century and was billed as the grandest summer resort in all of Muskoka, with room for 350 guests. Among its amenities: electric lighting, hot and cold running water, a post office, telegraph office, bar, billiard room, bakeshop, newsstand, barber shop and beauty salon. On the grounds (a little more than 50 hectares) was a golf-course, bowling greens, tennis courts, riding stables, and walking trails. It was a get-away for the rich and famous. But 50 years after it opened, in the spring of 1952, it burned to the ground, and its remains were summarily pushed into the lake.

I’d contacted a buddy who runs the marina at the modern-day equivalent of the Royal Muskoka (a J.W. Marriott resort) on the lake. I needed to complete one last skills-dive for a student doing a course with me, and a quick dip in the lake seemed like an easy way to accomplish it. He suggested going to the shore just off the site of the Royal Muskoka. There is a wall there that drops off to 45 metres and it’s close to the J.W.’s dock. Perfect. As a newly-certified diver himself, he was excited by the prospect of what my student and I might find.

I was less excited. Having dived in the local lakes on and off for more than 20 years, I knew that the visibility in most of them – especially the big three – could be hugely affected by tannic water with a similar level of transparency to a cup of strong Earl Gray tea.

Reverse of plate showing the effects of 60 years submerged

Well, I was wrong. Sure the water was the color of tea, but more like weak Darjeeling and perfectly acceptable so that, at depth, my student and I could see quite well… probably six metres or so. Certainly well enough to pick out lots of things that could have been relics from the Royal Muskoka, including a perfectly intact dessert plate: perhaps one of many laying at various points on the almost vertical wall.

My student completed her skills – timed staged decompression stops using breath cycles or drop in tank pressure and a knotted line on a DSMB rather than a depth gauge/bottom-timer: and surfacing with an unconscious diver from depth – and we celebrated her success by presenting our find — the perfectly intact plate — to our boat captain. He was ecstatic, and now wants to dive the area himself. I hope to make that happen sometime soon.

Face of plate found in Lake Rosseau

A memorable dive… because? Well, it’s cool to dive a spot that offers the chance of seeing and touching something historic, but more importantly, memorable because a new diver came away completely gob-smacked and excited about “local” diving without even getting his feet wet: although that’s not really true since the rain was coming down horizontally on the way back to the dock!

 

The Best Rescue Divers Don’t Have to Rescue

It may sound strange but it’s generally accepted that the best, most successful rescue divers don’t have to actually rescue anyone because they are able to recognize signs of impending panic and are savvy enough to intervene before true panic happens.

Of course, the question most aspiring rescue divers ask at this point goes something like: “Is that a learned skill, and if so, is it difficult to learn?”

The short answer is: yes it is, and no it isn’t!

When we imagine a rescue diver in action, what flashes before our eyes – initially at least – is an image of a neoprene-clad hero(ine) pulling an unconscious diver from the raging surf… Think GQ cover meets Surfer Magazine and you’re halfway there. Then after a few nanoseconds, the real image kicks in and it’s not so pretty; not as organized; and certainly not as heroic. The truth is that a full-blown rescue, as welcome as it may be in a disastrous situation, is simply something we should strive to avoid at all costs. In essence, a good rescue is one that may consists of a quiet word before the dive and either a change in the dive plan or a retreat to the nearest café for a coffee, a Danish pastry and a chat about tomorrow’s dive rather than today’s.

One of the pre-dive skills required in every technical diving program is something labelled stress assessment. This step in the pre-dive ritual is a vital “rescue” technique, and it applies to both self-assessment as well as buddy or team assessment.

Given that you and your buddy or buddies are certified, equipped and have the experience to enjoy your planned dive without undue risk, the day-by-day stock questions you should ask yourself are: Am I up for this dive? Do I feel good about the dive conditions today? Do I feel ready to do this dive? Am I comfortable with the things that need to be done to make sure this dive is fun? And finally, how does my buddy (or buddies) feel about the dive?

This step alone – coupled with honest answers and a real understanding that there is no shame in calling a dive at any time… even before you pull on your gear – goes a long way toward making you a “successful” rescue diver.

Speaking with divers following an aborted dive — a dive where things went absolutely pear-shaped — a sobering but not surprising statistic is the large percentage of them who say: “I just knew something was going to go wrong,” or “I had a funny feeling about the dive before we suited up.”

If a rescue diver has one simple but truly important task to do at the dock, on the beach, at the dive site before the actual in-water part of the dive starts, it’s to conduct a quick survey of every diver – including herself – to check if everyone really is happy with the dive plan and feels no pressure to do the dive.

During the dive itself, even without the use of diver to diver voice communications, there are ways to keep checking that everyone is happy. What are they? Let’s review the opening statement that was used to kick this article off… “Recognize signs of impending panic, and are savvy enough to intervene before it happens.”

This form of clairvoyance – being able to tell when something is about to fall off the rails and do something about it BEFORE it happens – is not telepathy or some other psychic power, but a perfectly attainable skill called Situational Awareness, and a good rescue diver needs it.

In the most general terms, situational awareness is perhaps the most under-rated, unsung components of safe and successful diving operations.

In advanced diving discussions, we have adopted the term Situational Awareness (SA) as a sort of catch-all phrase to describe what we mean when we say: “keenly aware”; and probably for good reasons. SA has been a core concept in high-stress operating environments, such as the military and aviation, for many years.

In these milieu, SA skills support the ability of individuals to handle complex and rapidly changing situations in which informed decisions – directly relating to personal and team well-being – need to be made under tight time constraints. In these high-stress settings, lack of SA is one of the primary factors in accidents attributed to Human Error.

For the purposes of rescue divers, SA is best described as being aware of what is happening around you and your team, and understanding how the flow of events, and the actions of team members will impact your dive’s goals and objectives; both now and in the near future.

It also encompasses the skill of selecting which bits of information are relevant and which are not and can be discarded.

Put briefly, SA is the chess-player’s skill but applied in an environment where checkmate can result in real physical harm, and not just a wooden game-piece being knocked sideways.

One key sign of a buddy’s comfort level while underwater is his or her respiration rate (at least on open circuit gear). A nice relaxed breathing rhythm generally means a nice relaxed diver. Faster breath cycles may be a sign of tension, carbon dioxide build-up, overwork, and are often the first outward sign that forewarns of events that can domino into bedlam if left unattended.

I have a good idea of my normal breathing rate during a moderate dive – it’s around eight per minute and therefore somewhere south of the adult resting average of 12 to 16 breaths per minute. I self-monitor during a dive, but I also pay attention to the bubble “signatures” of the divers around me, trying to pay particular attention to changes in the frequency of each diver’s exhalation. It’s certainly not a definitive marker of approaching problems, but a rapid increase in breathing is something a good rescue diver might want to pay attention to.

If your buddy starts to work hard and breath more heavily than usual, get their attention, slow them down, give them some reassurance — such as an OK sign and a squeeze on the arm — will show them that you are watching out for them. Something as simple as getting a diver to pause and wait for a few beats before carrying on can easily avert an unpleasant episode further along.

If you dive with the same crew on a pretty regular basis, you also learn other more subtle signs and body language that will indicate that they are less than comfortable.

As a rescue diver, it is always in YOUR best interest to pay attention to these little markers during a dive. Sure you may be capable of executing a perfect tired diver tow and safe ascent with a semi-conscious buddy, but why take the chance when that whole scenario can be avoided by stepping in a few minutes early?

A slightly different version of this article was first published in Technical Diving International’s eNewsletter in June 2013.

FREE C-CARDS…

Texting back and forth with a diver who’s signed up for some training sessions with me (he’s taking a Helitrox Deco class this spring), I was explaining which elements of his program are covered by my fees. And of course in that list of items, there was no mention of the c-cards that graduates get if they pass the course (with TDI this program comprises Advanced Nitrox and Helitrox Decompression Procedures, so two c-cards).

“How much for the cards?” He asked.

“Nothing,” I wrote. “The cards are free… you earn ’em. You can’t buy them!”

He texted back that he liked that idea. “Different to some other scuba classes I’ve taken,” he said.

This got me thinking about why, when I started to teach technical programs, I adopted the policy of “Giving Free C-Cards” to successful course graduates.

Students rarely fail the programs I offer. However, it’s not unusual for a student to have some challenges and have to do a few extra dives or work on their own for a while to grasp a concept that initially is hard to grasp… but an out-and-out fail is unusual.

Sometimes though, it happens. A student has a complete disregard for their teammates, they run out of gas repeatedly, they are simply not ready for “this type” of diving or do not have the required controls over body and mind in the water to be a technical diving. Usually, they accept my advice. Once or twice I’ve run into problems.

The one that made me very glad that I had adopted and advertized the policy that, “Your Card(s) are FREE!” took it really bad and reported me to the training department of the agency underwriting the course (which happened to be TDI).

In addition to the professional complaint, she had threatened a suit through small claims court under the assumption that her course fees included payment for c-cards. She was demanding at least that portion of the money she had paid, back. Her position was that she had paid for the course and expected to get her cards at the end of it.

Odd, don’t you think?

Anyhow, if you teach (tech or sport programs), here’s a suggestion if you do not so so already. Make it clear to your students that C-Cards are FREE, and that students earn them rather than buy them.

So, you travel with a rebreather do you?

I find myself traveling with a CCR more often than not these days, and most of the time, at least part of my journey entails airports and airport security. Surprisingly, I have few horror tales to share with you; in fact, just the opposite. I have found that with a little preparation and politeness — and leaving a few extra minutes between arriving at the terminal and my departure — things usually go very smoothly.

Let’s talk about the preparation part of the equation for a moment. Several years ago, Jill Heinerth mentioned to me that she put a note in with any rebreather kit she was carrying specifically explaining what the heck it was to security staff. I borrowed her idea.

The wording and the logos on the “letterhead” of the printed document I carry has changed a little over the years, but regardless, it always seems to work wonders. Here, for the record, is what my ‘official CCR travel document’ says.

NOTICE TO BORDER / AIRPORT SECURITY PERSONNEL

This apparatus is a Closed-Circuit Rebreather (CCR) diver life-support system and may be safely transported as cargo, checked, or carry-on baggage. The components of this CCR system consist of a scrubber head (containing a series of gas sensors and display handset powered by an encased standard user-replaceable battery); scrubber body (containing top and bottom screens, end-caps and a feed or deflection pipe); breathing loop (containing breathing hoses, Open_circuit Bailout valve (BOV), and counter-lungs); and two scuba regulator first stages each fitted with an array of low and high-pressure hoses. Additional open-circuit scuba equipment may also be carried with this CCR life-support system.

NONE of these components offers a threat to the security and safety of inspection personnel, other passengers, carrier vessels, buildings or other property, and all components conform to NOAA (National Oceanographic and Atmospheric Administration) and WRSTC (World Recreational Scuba Training Council) recreational scuba equipment guidelines for transportation by commercial carriers.

The individual transporting this equipment should be able to show proof of certification in its use and will be willing to explain its function to any security personnel upon request.

PLEASE NOTE: Any pressure vessels (scuba cylinders) accompanying this CCR life-support system MUST be dismantled and have valves REMOVED in such a way that visual inspection of the vessel’s interior is facilitated (as per TSA/FAA ruling). Failure to conform to this stipulation voids this document.

You may find that printing this out and putting it in your baggage with your rebreather helpful.

How much of a conservative are you?

When it comes to storage and use of the ‘kitty litter’ used in rebreathers to scrub carbon dioxide from the breathing gas, I had until very recently thought of myself as ultra conservative. Turns out this was not necessarily the case.

I was careful with the storage part and careful when packing or loading the scrubber canister of any unit I dived with, but it turns out I misunderstood the actual working life of the absorbent once it was partially used.

Now I should make it clear that the only absorbent I have much experience with is Sofnolime® 797. This is a product made by Molecular Products in the UK and – in my circles at least – is the gold standard for use in closed-circuit rebreather diving. For the record, I use what’s called the non-indicating variety, which means it does not change color when suffused with Carbon Dioxide.

Sofnalime® itself looks a little like a white version of the material used in a cat box (hence its street name), and is actually a triangular cross-sectioned extruded pellet made in part from calcium hydroxide with a little sodium hydroxide mixed in, and is between 1.0 mm and 2.5 mm in size. It is alkaline (a pH between 12-14), slightly water soluble, and non-corrosive – but the dust will irritate the eyes and perhaps the skin, and inhaling it is a definite no-no.

In simplest terms possible, the chemical reaction that takes place inside a rebreather’s scrubber removes carbon dioxide and produces heat and water, and turns the soda lime into chalk (calcium carbonate). Also, for the record, in addition to proper storage and handling of unused scrubber material, used soda lime should be disposed of responsibly. Whenever possible, I take it home and then spread spent scrubber material on the garden where horticultural lime might be indicated, and put the rest in our horseshoe pit.
Ok, now with that clear, let’s focus on my misunderstanding.

Rebreather manufacturers tend to rate the working life of the scrubber material in their units based on the size of the scrubber canister. Literally on the amount of kitty litter their machine holds. In a perfect world, we might ask for a slightly more scientific method to gauge this, but referring to an X-hour scrubber is the norm. Certainly, this is what I was taught… but it is not what I teach; and here’s why.

After speaking with one of the chemists at Molecular, I learned that the method commonly used to indicate the effective life of scrubber material (i.e. Sofnalime®) is incorrect. While a freshly charged scrubber may have X or Y or N hours of potential effectiveness ahead of it, that number of hours is an estimate based on continuous use.

Let’s say for example that a rebreather manufacturer designates its scrubber duration as four hours. This means up to four hours on one dive and NOT two two-hour dives back-to-back on the same scrubber. This, according to Molecular’s chemist, would be “pushing it.” There are several other considerations that should be taken into account when estimating how much ‘life’ is left in one’s scrubber but on straight, no frills, moderate depth dives (such as shallow cave dives in North Florida which would normally be to depths less than 30 metres/100 feet) after one two-hour dive on a ‘four-hour scrubber’ perhaps only an hour and a half is left, and NOT two more hours. After a couple of one-hour dives, a third dive to 45 minutes or so, will all but exhaust the remaining Sofalime® so that in actual use, the effective life – and safest interpretation – of a four-hour scrubber would be less than three hours.

Now, it should be said that estimates of scrubber duration from manufacturers tend to be conservative and are usually based on the worst type of conditions; however, I found it interesting that the guy who oversees the manufacture and testing of the active component in the little chemistry set I lug around on my back to go diving, is more conservative yet.

And I for one will follow his example from here on in.

A word or two about underwear…

What is it about the European’s and drysuits? During the past ten years or so, I’ve owned and worn six drysuits representing five different brands. Their design and materials used are different and they’ve helped keep me warm and dry for working dives and personal dives in a lot of different locations. Well, most of them have kept me warm and dry. The only suit made in the US, was a terrible investment spending more time going backwards and forwards to the manufacturer in California for “repairs” than in the water. So let’s forget that one. The other five suits are from four manufacturers based in Germany, Poland and the UK. All five suits (two from the same company) performed and continue to perform well and remain “onLine” in the Dive Locker at home ready to do service.

Now six suits over ten years is going some! Most active divers might need two suits over a ten-year span, but in my defense… well, I don’t have a defense. Truth is that I have more suits than I need. Another truth is that for the majority of my dives over the past year, I have worn suits from one single UK-based manufacturer because they are both outstanding performers. A slight conflict of interest here. A company that I do consulting work for recently signed a deal to distribute this brand of suit in Canada and the USA. However, they did so based on the feedback of several consultants they use (including me) who had been diving the suits for a year or so. Bottom line is that we liked the suits, and our advice to our client to represent the line was based on the product’s performance rather than profit margins.

Anyhow, as you know, a drysuit is only half of the system designed to keep a diver protected from the elements. The other half are the thermal undies worn under the suit. For the record, I have more of these than I have drysuits — two-piece, one-piece, light-weight, fluffy, heavy-weight, fancy and plain. A drysuit is important. Fit, comfort, dryness and its profile in the water are critical issues, but all (in the case of shell suits) or a portion (with neoprene suits) of the actual thermal protection a diver needs to stay alert, warm and comfortable in the water comes from whatever it is the diver wears under his/her suit.

Because of this perhaps, I am even more critical and more detail oriented about the thermals I wear than the drysuit that goes over the top of them. Most of the thermals I have bought or been given over the years no longer go near the water. They are too bulky, too restrictive to allow free movement, and are a drag to dry after a day on a boat or at a cave site. These I wear to walk the dog and shovel snow in the winter. I have quite the selection, and Brad — the ex-seeing-eye German Shepard who enjoys walks in the snow and helping me move the stuff from around our house — knows that when I pull a set on during the day, it’s time to go out and play. He does not dive.

What I look for in drysuit undies is really pretty simple. I find changing conditions, and water temperature at various dive sites ranging from more than 20 degrees (C) to less than 0C (winter sea water) lend themselves to a layered approach. A good base layer will work on its own for warmer temperatures and a good extreme top layer extends the comfort zone through MOST colder water. For really cold temps, a heated vest is the best solution.

I do a lot of diving in the Great Lakes and the conditions there present an additional challenge. Summer air temperatures can be in the 30s and water temperatures at depth are a pretty constant 4 degrees C (the temperature of water at its densest). This too calls for a layered approach with the layer closest to the diver’s body capable of providing good thermal protection while wicking away the inevitable perspiration that results from putting on warm garments in summer weather.

So, I am on a constant lookout for thermals that suit those varied needs. It also helps if they pack small, dry rapidly, and are made well enough to last more than a few dives before seams let go or become unravelled.

A month or so ago, I was in the UK doing a factory inspection of the O’Three facility in Dorset. The company’s drysuits are spectacular. The owners of the company have been pushing their undergarments to me for a while, and during my trip to see them in the UK, I was convinced to give their Point Below Base (PBB) system a trial at the first opportunity.

That opportunity was earlier this month, cave diving in Marianna in Florida’s pan handle. Conditions were perfect for this type of trial… Water temperatures ranging from 17 to 20 C and air temperatures all over the map from about 25 as a high and minus 3 at the start of the day on a few occasions.

The O’Three PBB+ Thermals performed very well and I am impressed. They were actually warmer than a much bulkier 200 gram one-piece suit with light wicking undies underneath. After two-hours in the water, I was as warm as toast and multiple dives were not a problem.

The PBB+ is a two-piece system consisting of a farmer john-style pants and bib with a pullover top to protect the arms and to give a little more insulation to the core.

You can read a much more detailed account of the technology, features and benefits on O’Three’s website:

http://www.othree.co.uk/products/thermal-15/pbb-2.aspx

But the Cole’s Notes version is simply this: I like the design, the materials, the insulation factor*, and PBB+’s ability to wick away moisture and dry quickly when it does get wet. Frankly, if you’re anything like me and always on the look out for something to keep you warm on those long dives, this may be the answer.

A little plug: O’Three products including PBB undies are priced competitively here in North America and available from Silent Diving LLC… or me. </commercial break>

*As an aside, I do not know how relevant readings for garment insulation based on Clo or Tog units are to describe the performance of drysuit underwear… and in any event, I have no idea if anyone at O’Three has bothered to rate their PBB+ thermals, but I also own a one-piece thermal suit from a rival manufacturer that is rated to 1.45 Clo, and the PBB+ system was warmer, and way more comfortable, and less bulky. Viva new materials… Viva new technology!

Questions to ask – and answers to expect – when you research which CCR is right for you…

Let’s take as given that your research so far has turned up that the type of diver you are, and the type of diving you like to do – now or in the near future – makes you a good candidate to invest in a closed-circuit rebreather.

 

So far, so good, but now you need to pick which type of rebreather is going to be the best investment. You can find plenty of help on that score… almost every CCR diver thinks his or her unit is the best around, and in a way, that can hardly be surprising since they’ve invested a lot of money and time into it. And admitting you made a mistake of that magnitude is tough for anyone to admit to.

 

The decision-making process WILL be easier for you if you can log a few hours on various units BEFORE making any final commitment. And the rather worn out advice that it is not the agency that counts but the instructor is actually very true with CCR training, so picking the instructor can be as important as picking a unit.

 

But all that said and done, there are some fundamental questions that you should be armed with before you hand over the admission fees to diving without bubbles. The list below contains a few that I think are important. Look them over. I hope they help. Let me know what you think.

 

Is the CCR you are considering CE approved? It should be because CE approval connotes rigorous third-party testing for important performance issues such as work of breathing and overall functionality.

 

What is the tested depth rating? Some manufacturers put a depth limit on their gear and diving deeper than the depth recommended in the user manual is simply a poor judgment call.

 

Does the CCR you’re looking at have Over the Shoulder (Front) or Rear Mounted Counterlung design? There really isn’t a great deal of difference between the two, but there are advantages to each. As far as I know, only one manufacturer offers divers the choice with BOTH options with both carrying CE Certification.

 

What type of Oxygen Injection System, is used in the CCR you are looking at? Options include a Constant Flow Orifice, diver adjustable Variable Flow Orifice, a Static Solenoid or a Dynamic Solenoid. If you are looking for a CCR with the option of automatic set-point control, look for one with a Dynamic Solenoid capable of delivering continuous and instant reaction to changes in oxygen partial pressure in the diving loop.

 

If the unit uses oxygen controllers (has an automatic option) does it have independent dual controllers? It should do otherwise there is no backup in a system that is vital to life support.

 

How well will it maintain constant PO2 during ascent? This really comes back to controllers. During ascent the partial pressure of oxygen in the diver’s breathing loop can drop dramatically and even to hypoxic levels as the ambient pressure drops. Unless the CCR’s oxygen controller has the ability to react correctly and rapidly to these changes, the diver is at serious risk and the unit is poorly designed.

 

Does it have a CO2 Scrubber performance monitor? The scrubber bed is where carbon dioxide is removed from exhaled breath. There are several factors that can have a negative effect on its performance and how effectively it does its job. Since the chemical reaction that takes place in the scrubber material generates heat, a smart way to monitor performance is to measure which portion of the bed is “hot” and display that to the diver.

 

Does it have a CO2 Sensor? By following a few basic “rules” and sticking to certain guidelines, CO2 breakthrough can be avoided, but many divers feel more comfortable and secure with this type of sensor in place. If you’d like one, is it available on the CCR you’re considering?

 

Does it have Heads Up Display (HUD) and what information does it show to the diver? An HUD is a useful tool, but some are confusing and seem less than intuitive. An HUD should convey exactly the information necessary for the diver to fly the unit safely, and this includes warning when PO2 is outside set parameters, when battery power drops, and when the scrubber bed is reaching the end of its effective life.

 

Does it have real-time Nitrox / Trimix Computer designed and manufactured by the same people who built the CCR? It should. Some CCRs use controllers and computers from third-party suppliers. This may suit some risk models and business plans, but this approach is outside my personal comfort level. Of course yours may vary, but I like these two “bits” of my CCR to be integrated. I also think it helps when the Quality Assurance that keeps me safe on the rebreather extends to the computer feeding me information about CCR function and my decompression status.

 

Does the CCR you’re looking at have Automatic Depth Setpoint switching, and can that auto function be overridden simply without lots of button pushing? This is a good feature that can help to manage the risks of decompression stress, among other issues.

 

Does it have audible and visual alarms for crucial issues such as low or high PO2, high CO2, and scrubber life? These items are critically important. I try to dive my unit so that no alarms are triggered, but it’s nice to know there’s a back-up.

 

Are parts and service availability worldwide? If you travel, it would be nice to know that in the event of something breaking, a replacement part is not sitting in a warehouse someplace on the other side of the world and a several days away from access to world-wide shipping.

 

How much service is required? Good industrial design and well made parts put together in an ISO 9001 factory rather than outsourced to the cheapest off-shore knock-off house cannot come close to a 100 percent guarantee that things will work as expected, but they help us to come close.

 

Is there a backup power source? If a machine uses battery power to function, then there should be an independent backup battery pack and a mechanism to switch seamlessly from one to the other should it be required.

 

Can it be upgraded for Technical Trimix Diving? Not all CCR divers are interested in technical diving, but if you one day decide to take up technical diving, ask yourself if will you have to sell your unit and start again with a new model.

 

Does it have PC Interface and Dive log download? This is a nice feature to have at any time, but it becomes amazing when you can send that log to the manufacturer for system diagnostics.

“What could possibly go wrong?”

For a quick and dirty definition, you might say that planning for a technical dive is mostly about working out how to deal with contingencies when something hits the fan.

Of course that definition does beg a few questions: for example, exactly which contingencies does one have to deal with during a technical dive, and how fast is the fan likely to be spinning? But as a starting point, and in particular when trying to explain what the sport is all about to someone who is neither trained in nor familiar with technical diving, it works as well as anything else.

One of the first instructor-trainers I worked with was extremely fond of charts and graphs. His students left his workshops and classes with the impression that he had pie charts, bar graphs and spread-sheets of stats for almost everything related to diving. He could tell you what percentage of aluminum 80 cylinders made in a particular year by one or two manufacturers were painted red; or the total number of snorkel keepers that sat unused in the bottom of save-a-dive kits world-wide; or how many open-water divers out of a graduating class of, say, 100 would go on to become dive masters. Totally worthless information in most instances, but what it lacked in usefulness was compensated for in a perverse way by him having lots and lots of it.

Naturally and in accordance with the laws of nature, hidden away among the chaff were a few kernels of useful data too. For example, he had a chart showing the average number of catastrophic gas emergencies year by year per 1,000 dives by certified cave divers.

Much to my disappointment, I am unable to remember any of those figures – useful or otherwise – and in any event I was reasonably sure at the time of first hearing that a good percentage of his data were suspect and most probably thrown together the evening before he was due to share them with us – his eager new instructor candidates. I believe a good number of them were creative artifacts crafted in-situ, so to speak, to add an atmosphere of scientific sincerity to his otherwise wildly entertaining, right-brain presentations.

However, what I can remember was a favorite phrase he used when outlining for us what was involved in his version of contingency planning – “covering your arse” – whether diving on our own, with buddies or with students.

“You can, without much real effort,” he would say. “Contingency yourself right out of the water, and quickly arrive at a point where any and every dive looks too risky to undertake…”

During one presentation, he said: “Let’s take as a given that poor safety engineering in life-critical systems such as low-cost scuba regulators is reasonably commonplace.” He explained that based on the average diver’s yen to save a buck on kit, you could easily create a hugely pessimistic risk assessment for that average diver: especially if you wanted to factor in bad habits like not doing proper pre-dive checks.

Following that logic, and considering the magnitude of loss associated with diving accidents (the threats of death by drowning, embolism, oxygen toxicity, severe decompression sickness, et al) any argument that the probability of said failure is unlikely was smothered.

“Quantitative arguments about kit being unlikely to give up the ghost and go pear-shaped,” he told us; “Are moot if we were to agree that the common human reaction to component failure is panic: and since we cannot reduce instances of component gear failure to zero, and panic usually results in death or injury, diving is unsafe and should never be attempted.

“Clearly this is, to a great extent, bullshit,” he said, “Otherwise we would have to wade through a slurry of dead people at every dive site we visit. But it’s worth noting that people die sometimes for no better reason than they were surprised and unprepared.” He wrapped up the lecture by explaining that the secret is to know what has the shortest odds of actually going wrong on a dive and focusing one’s primary efforts on that, but also being prepared for the unexpected.

A rational and reasonably careful look at the situation makes it obvious that all the threats presented by diving can never be eliminated. So if we want to dive, we have to learn to be happy with an action-plan that deals primarily with threats that are real and that might actually happen. And when we have that sorted out, and before venturing deeper and longer than a sport dive, we should include cover your arse strategies for the unusual… because Murphy is a devious bastard.

I should admit that I am lazy. If there is an easier way to be effective, I’ll find it; and if it’s possible to reuse something again and again until it’s frayed and worn thin, I do so without much hesitation. There are some provisos but those are my guidelines… especially for contingency dive plans.

I am a huge fan of using and reusing the Apex Dive concept. The definition of apex dive that I use and teach is that we can separate various dives into categories by considering the equipment and training required to do the dive. To some extent, the depth and gear limits outlined in most of the technical dive programs I teach, help to draw hard lines around the otherwise ill-defined concept of a “Technical Dive.”

For example, one category of apex dive is for an open-circuit staged decompression dive in open water from a “starting” depth of 30 metres (100 feet) to a maximum depth of about 45 metres (that’s around 150 feet to my non-metric American and Canadian friends). If we add to this the limits we accept is we will use one decompression gas and work within the gas volume rules for only two cylinders of bottom-mix, we have defined the apex dive for graduate from a TDI Helitrox Decompression Program.

I have written down and available in my kit a “simple” action plan for this level of dive, and it includes set waypoints, maximum duration (given a specific minimum starting gas volume), ascent schedules, bailout schedule, lost gas plans, bailout scenarios, what to do if various pieces of kit fail, how to and how long to conduct a search for a lost buddy, how to bring an injured or unconscious buddy to the surface, and so on and so forth.

This apex dive plan is designed to be used with ANY O/C dive at this level or shallower and shorter. I use a similar approach to other categories of dives to greater depths (60, 75, 85 metres for example), and shallower (to depths of only 30 metres specifically), and for dives in different environments such as caves. I also have a similar array of plans for similar dives on a closed-circuit rebreather.

Much of a plan laid out at one level, is almost exactly the same as the plans for dives at the level below or above. The gas management plans, ascent and bailout schedules change of course, but a lot of the scaffold keeping the plan upright, is common across the board. Also for each of these dive plans there is a segment you could call the “it’s been a really bad day” scenario. The situations covered in this are the ones that are unlikely to occur, but which carry with them, a really serious magnitude of loss.

Some of these situations are the “contingency yourself out of the water” scenarios that my old IT told his classes about. Notwithstanding his advice to “ignore the unlikely,” it seems prudent to me to have something in place to deal with several of the unlikely possibilities when diving deep and long.

For example, I have nothing that will help me deal with a lightning strike while hanging on a decompression line, but I do have a plan to help get me back to the surface with a broken buoyancy device. As unlikely as it is that a wing would spring a catastrophic leak underwater, most wings used in technical diving do have a ludicrously venerable weak point: the 15-cent plastic elbow that connects its inflation hose to the body of the wing itself.

While judicious handling during transportation, a good assembly and pre-dive inspection, and a bubble-check before descending can all help prevent this particular failure, losing a wing at depth would be serious, and in most cases could really ruin your day.

At some point in the past, you have probably heard the advice to dive a balanced rig. A balanced rig is, according to a definition just read on Wikipedia and a couple of diving websites, a rig that a diver can swim to the surface from depth without the help of a wing/buoyancy device when the cylinders are empty because it will then be “neutrally buoyant.” Someone with a rudimentary understanding of dive kit and basic physics might read the previous sentence and tell themselves: “yea, sounds legit.” The rest of us may be left with some nagging doubts.

For example, what’s with that “neutral with empty cylinders” nonsense? I am a fan of divers NOT getting into the water with too much ballast but cylinders are never empty and since whatever gas is in them has mass, surely in a balanced rig/broken wing scenario, gravity is going to win.

In my opinion, we need some alternative to swimming our kit and ourselves up from depth without ANY assistance. As luck would have it, we do not have to look far for some solutions.

Unlike most sport divers, few open-circuit technical divers have truly ditchable weights. Their ballast is supplied by integral items of kit such as steel primary cylinders and a stainless-steel backplate. Sidemount divers may have the option of dropping one primary cylinder if needed, but divers wearing back-mounted doubles do not. Therefore, in the event of a wing failure – however unlikely – a good plan is to have some back-up buoyancy or a structure plan that includes some potentially helpful suggestions.

Here are a couple of tactics that may help you if the inflation hose and your wing become separate entities while you are faced with a long ascent between you and a cup of hot chocolate back on the surface.

My council would be to forget trying the “swim up balanced kit” technique. By all means work on the principal of wearing a “balanced kit,” but understand that a long staged-decompression ascent is not something you want to undertake as a continuous swim.

If there is structure nearby – a wall, shelf, wreck whatever — use it to stabilize yourself. Grab it, get yourself sorted out, “talk” the situation through with your buddy and try to relax. Unless your wing failure was accompanied by a huge loss of gas from your cylinder, you have something to breathe while you think. Relax and work out your options. If there is no structure, grab your buddy and use them as a stabilizer. It’s surprisingly simple to hang onto a buddy’s harness and let them add a little additional gas to their wing to support the two of you. But it does require a little practice!

Let’s assume you are wearing a drysuit. Add a little gas to it to offset gravity a little. You may be lucky and your suit may be all the help you need. Keep your buddy or buddies close, and start your ascent. Good luck and let’s meet up for a coffee sometime… but chances are that your suit may not overcome gravity’s pull completely.

If there is an upline, make for it and use it. At this point it may be worth noting that a prussic loop can be useful place to hang from while you work on options. A prussic is simple to tie to an upline and can be used just as effectively as an ascender is used in rock climbing (their original application). I carry a length of 3mm equipment line tied in a long loop in my wetnotes for this reason.

Things should be golden with the combination of a solid upline, a drysuit and a prussic loop, plus the administrations of your buddy to help with stage deployment etc. as needed. But what if there is no upline.

This would be a good time to send a DSMB aloft. Actually, it may be prudent to deploy a DSMB even if there is an upline, depending on how your surface support has been briefed. With the exception of the very smallest, silliest “safety sausage,” a DSMB (a Delayed Surface Marker Buoy) should provide sufficient lift to support a diver in place of a wing. If you have the choice, you may prefer to hang from a line attached to a small cave or wreck reel rather than a spool in this situation, but either works just fine… and spools rarely jam or bird’s nest.

In several thousand dives, I have had one wing failure and one buddy have a complete failure. I have conducted a couple of test dives with the dump valve removed from my wing – just for the fun of it – but only one real-world failure. Therefore, the weight of logic and statistical evidence is on their side of the argument that states that this type of gear failure is highly unlikely. It really is, and chances are it will never happen to you at any time. However, next time you have a dive planned with your usual buddies at a site with a hard bottom within sensible distance of the surface, and you have nothing better to do, try this. Empty your wing completely and get yourself back to the surface using an alternative method. You will certainly learn something about yourself and possibly your buddy, and most likely you’ll have fun too.

Remember as well, it does not take much to contingency yourself out of the water, but with a little forward thinking, planning and practice, there is no need to.