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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A surprise lesson…

LongO'THREE

There are plenty of incentives for taking part in a scuba diving ‘expedition,’ and some of them at least, may not obvious at first sight.

The best, and a motivation with all the enticement of a chocolate-chip cookie in the eyes of the average six-year old, is to learn something new. Coming a very close second – with the pulling power of a chocolate- dipped coconut macaroon in my world – is having a tightly-held, but wrong-headed notion, kicked into the trash, and replacing it with an idea backed by science, logic, and responsibly collected data. Again, a learning experience.

Earlier this year, Jill Heinerth and I were asked to put together a small expedition to do some work in the Bell Island Iron Ore Mine, in Conception Bay, Newfoundland. We had both been there before, and we were both huge fans of what the place has to offer: essentially, the chance to experience truly unique dives in an environment that screams history and heritage.

There were tonnes of other reasons to sign on for this particular expedition, but diving in what is essentially an underwater museum, was pretty high on the list.

A total surprise – and an unexpected bonus – was having my opinion about heated vests and their potential role in diver safety – specifically decompression stress – turned around about 180 degrees.

The lesson went something like this.

Dr. Neal W. Pollock was part of the Bell Island project, gathering data for his research at Divers Alert Network. Neal is research director there – at DAN – and a senior research associate at the Center for Hyperbaric Medicine and Environmental Physiology at Duke University Medical Centre. And when not pushing an ultrasonic transducer against your rib cage, he’s a handy guy to have around when the chatter turns to many things related to technical diving.

I’d seen Neal’s presentation on Thermal Physiology and Protection at Rebreather Forum 3.0, in Florida a few years before. But, frankly did not really grasp his message. Then, sprawled on the floor of the Bell Island Museum and watching a whole stream of gas bubbles race around in my heart after a dive, helped me – and others on the expedition – listen a little harder to what he was telling us.

A link to his presentation at RB 3 is at the bottom of this page, and if you dive at all, you’d do well to watch it, but the Coles Notes version is this.

If, like me, you figure the safest way to dive is to be warm throughout, you may want to rethink your approach.

Dr. Pollock, suggests that there are three issues to think about when we consider thermal protection. Number one, at depth we must be able to function; secondly, we must take into account the effect of temperature on our decompression stress; and lastly we need to consider comfort.

Based on a “small but significant” study conducted by the Navy Experimental Diving Unit, Dr. Pollock explained: “Divers tend to put the emphasis on the wrong thing… comfort.” And comfort, according to the data, and Dr. Pollock, “should only be a distant third.”

The NEDU study found that the fewest instances of DCS occurred in divers who started cold, and finished warm. Probably the exact opposite of what happens on a significant number of technical dives. Worth noting is that for this study, subjects wore no thermal protection and worked in water at 36 degrees (warm), and 27 degrees (cold).

Significant also was that there were zero cases of DCS in 80 “cold start, warm end” dives, but in warm/cold dives, probably the situation for many long dives, seven out of 32 (22 percent) resulted in DCS. The dive profile incidentally was a seemingly benign 120 fsw with 30 minutes of bottom time and 91 minutes of deco!

When the dive profile was appreciably altered to be more aggressive – 120 fsw for 70 minutes of bottom time but with an unchanged 91 minutes of deco – the results had very similar implications: cold/warm dives resulted in 0.1 percent DCS.

Of interest to those of us who own and use heated drysuit under garments, warm/warm dives following the same profile, returned a 17 percent instance of DCS (four cases in 24 dives).

thermalimpactdcs

A slide from Dr. Neal Pollock’s presentation

For technical divers, there are many, many factors with a role to play in decompression stress, but consider this. With a heated vest, several things might happen. The vest is turned on and keeps you warm throughout your dive. The vest is turned on to start the dive, and then is turned off or runs out of power at the end of the dive. The vest is turned off to begin the dive and left off when you start to get chilled as bottom time passes, and only turned on during the latter stages of decompression (probably NOT the most common practice).

Based on the NEDU study, each has possible consequences, and not all of them positive. It would seem that the best option in terms of thermal status, is to start cold and end warm.

As Neal remarked, the NEDU study was across a very small population (73 divers), and one has to take that into consideration when assessing its value and relevance. However, my personal observation of what was happening in my heart after a 90-minute warm/warm dive – thanks to the transthoracic echocardiogram being orchestrated by Dr. Pollock about 20 minutes after I surfaced – is that I won’t do that again.

 

 

View Neal’s RB3 presentation here… and in addition to a much more complete interpretation of the NEDU study, he covers several other related and significant issues… watch it.

https://www.youtube.com/watch?v=yixnr07AiTI

 

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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.

Mine Quest 2.0

Bell Island Mine 2.0

Winter in Newfoundland can be bleak and is most definitely cold, but this week, a group of volunteers and Bell Island Heritage Society staff ignored the weather and did a huge amount of setup work getting things ready for Mine Quest 2.0.

As well as building a platform/staging area for the exploration team to work from, during mid-February’s expedition, they carried several hundred kilos of materials more than 225 metres down a ten-degree incline from the surface to the water’s edge. Before the building commenced, using pickaxes and shovels to clear away loose rocks from the roof and walls of the mine shaft, then installed temporary lighting.

mineshaft

After the clean-up… the mine shaft we will be working from

Eventually, it’s hoped the mine on Bell Island will feature permanent infrastructure that will add dive adventure tourism at the historic site to the world-class wreck diving found just off the island’s coast. For the time-being, the hard work will help simplify, and aid the success of an effort to add the the two kilometers of passage explored and lined during the 2007 project I was lucky enough to be part of.

Over the next several weeks, and certainly during Expedition Week (February 13 – 20), I’ll try to keep you up-to-date on progress and exactly what’s planned.

 

In the meantime, hats off to Mark ( Magoo) McGowan, John ( Johnny O) Olivero, Nick Dawe, Kyle Morgan, Rick Stanley, Ron Reid, Teresita ( Teddy) McCarthy, Des McCarthy, and Tom Spracklin.

Thank you for your efforts folks.

 

For a comprehensive line-up of who will be working on the project, visit my friend and co-leader’s blog… Thanks Jill.

http://www.intotheplanet.com/newfoundland/