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:


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.


Hi: and congratulations on your new open-water certification. Diving is extremely cool and I hope you get as much out of the experience as you can: talk about opportunities… wow!

You probably do not recall everything you read while doing the academic work to earn your certification, so I would like to take this chance to remind you of something important: An overhead is no place for an open-water diver: period. There should be no exceptions to this.

I’m writing to tell you this because there is a chance that sometime soon, someone – perhaps a buddy or a more experienced diver, maybe even an instructor – will try to tell you differently. Please tell them they are wrong. You can quote me if you like, and you can use stronger language too, but much more importantly, you can find the same advice in training manuals from EVERY agency and any reputable dive professional. Please take the time to check this out.

Caves, caverns, and the inside of wrecks, are NOT places to find yourself without specialized training. And I do not mean advanced open-water, or rescue diver or even a divemaster or instructor training but specialized training in those specific environments. If the person, even an instructor, trying to get you into a cavern or cave, calls you a wimp or says that everything will be OK as long as you “stay close and follow me,” please walk away. It could save your life and in any event, will send the right message.

If they are an instructor, suggest they reread their standards and procedures manual – it really does not matter which agency they teach for because they ALL forbid this sort of behavior and this type of dive. Fact is, suggesting that you let them “guide” you into an overhead environment could get them reprimanded and their teaching status suspended.

A few days ago, a buddy of mine pulled an open water diver out of a cave in North Florida. Against all odds in this sort of scenario, she was alive… shaken, but alive.

Her explanation was that she went into the cave just to take a quick peek at what was in there because someone (her Dad) had convinced her that as long as she did not go in too far, she’d be fine.

In a perfect and just world, she will be able to sit down sometime soon with her idiot father to have a chat. She almost died. She would have died if my friend had not been there to find and save her. (He is, by the way, a very experienced cave instructor and explorer.)

OK, so here are some things to think about. Untrained divers kill themselves in caves with sad regularity. This has been happening for years and unfortunately continues to happen even though it is preventable. People who should know better and who have read the “rules” choose to ignore common sense and believe they are immune from the laws of physics… and Murphy.

The poor sap who ends up dead may have been told that caverns and caves are safe, and believed it. They may also have been a super master specialty open-water instructor and have a collection of badges as long as their arm, but all that means bugger-all inside a cave when they realize they are lost, are sucking seeds and stems from their almost depleted single cylinder, and start to claw at the limestone ceiling and walls wailing for salvation.

Caves can be beautiful but that beauty can become extremely ugly in a couple of heartbeats. Here are some things that have happened to untrained divers who almost died in a cavern or cave but somehow managed to find their way out.

“We only intended to swim in a little way, but there were lots of passages and we got turned around…”
“The water was really clear but my buddy crashed into the bottom and I lost sight of him and the exit. I think he is still in there…”
“We had a light between us but it went out. It was really dark and I kept swimming into the walls…
“I swum in a little way and then my octo started to freeflow…”
“We followed a line and it just stopped and then I got tangled in it…”
“I panicked when I turned and could not see the exit.”

There are no grey areas when it comes to this overhead stuff. Going in there without the right kit and training is seriously tempting fate, and there are so many other ways to enjoy yourself with scuba. Please, please, do not go into an overhead until you get training in overhead diving and get yourself some serious kit and gain the experience to use it properly.

Thanks. Now go dive… in open water.

Steve Lewis
TDI instructor trainer #6

The Five-Minute Neurological Exam: don’t leave home without it!

I was somewhat surprised to learn that although the majority of technical divers believe in the value of the simple neurological exam — taught to students during decompression courses to identify signs of potential DCS — few carry a printed copy (or pdf on their phone or tablet) with them on their dives.

What follows is ONE of several versions that exist.  I use it because it seems the most comprehensive and straightforward. Regardless of if you opt to use this or another, remember to record the results, and in particular to note any abnormalities. If a dive buddy is evacuated for evaluation at a hyperbaric facility or even a hospital emergency department, sending a notarized copy of this with them may help them get treated more rapidly.

There are NINE test categories… #  1, 7 and 9 are key.

1. Orientation (these may sound facile but they may indicate real confusion in a otherwise normal-looking victim… do not omit them).

  • Ask diver for full name and age
  • Ask diver to state present location
  • Ask diver what time it is, what day of the week, the date and month

2. Eyes / Vision

  • Ask diver to count the number of fingers you display (do this several times using different numbers)
  • Check eyes together and then separately
  • Ask the diver to describe a distant object… something several metres (yards) away at least
  • Have diver follow your clenched fist with his/her eyes as you move it up, down, left and right in front of their face. Have them hold their head still and check that their eyes follow your movements smoothly
  • Check both pupils are equal in size

3. Face (muscles and nerves)

  • Ask the diver to smile and check there is symmetry in their expression
  • Have the diver whistle. Watch the “pucker”. Note any drooping of lips.
  • Have the diver close their mouth tightly and feel that their jaw muscles are equally tight
  • With their eyes closed, stroke the diver’s face, forehead and neck and ask them to describe the sensation. It should be similar

4. Hearing

  • Check hearing by rubbing your thumb and forefinger together with the diver’s eyes closed. See how close the fingers have to be to be audible.

Note: If the surroundings are noisy, ask bystanders to be quiet and have noisy machinery turned off if possible.

5. Swallowing Reflex

  • Have the diver take a sip of water and watch their “Adam’s apple” as they swallow to be sure it moves up and down

6. Tongue

  • Have the diver stick out their tongue. Note if it droops, moves to one side or other abnormal movements.

7. Muscle Strength

  • Place your hands firmly on the diver’s shoulders, have them “shrug”. Note if there is any difference in strength
  • Have the diver squeeze your fingers with both hands at the same time, notice any difference in strength. Have the diver hold his hands together at chest level and elbows high. Gently push and pull the elbows while the diver resists the movement. Notice any difference in strength
  • Check leg strength by having the diver lie flat and raise and lower the legs while you resist the movement

8. Sensory Perception

  • Check the diver’s ability to feel you touching them lightly starting at their shoulders and working down to cover their entire body. Compare degree of response on each side. The diver’s eyes should be closed while this is done.

9. Balance and Coordination

Note: Be prepared to protect the diver from injury when performing this test.

  • If possible, have the diver walk heel to toe and check balance and coordination. Make sure the diver does not fall!
  • Have the diver stand with feet together and eyes closed. Ask them to hold their arms straight out, and hold that position for half a minute at least. Be ready to catch them if they lose their balance or fall.

After the exam…

The diver’s condition or the environment may prevent you conducting one or more of these tests. Record any omitted test and the reason.

A cycle of tests should be repeated at 30- to 60-minute intervals while awaiting assistance in order to determine if any change occurs. Report the results to the emergency medical personnel responding to the call.

If there is a delay getting to a suitable recompression facility, repeat the test hourly.

Technology and Technical Diving… these are not your granny’s computers

(A very similar version of this article was first published in issue 24 of Underwater Journal, an underwater adventure magazine)

With the rising popularity of sidemount diving, semi-closed and fully closed-circuit rebreathers, and of course the ubiquitous popularity of traditional North Florida Cave diver’s kit (doubles, manifold, backplate and wing), it sometimes easy to forget that the majority of divers still manage to have plenty of fun underwater wearing a single cylinder!  A single cylinder is simple, comparatively light-weight, easy to set-up and operate, and is without doubt the most common kit configuration among scuba divers around the globe. But as popular as it is, a single cylinder does have one huge drawback, and a growing number of recreational sport divers recognize the short-coming and have opted to do something about it.

Chances are good that if you are a graduate from an SDI Solo Diver program, or if you came up through the University of Hard-Knocks, you probably already know that one huge drawback is that the diver has very limited options when Murphy tags along as a dive buddy. For example, with only one regulator first stage, the only backup life-support system is your buddy’s octo. A massive free-flow really gives little alternative but to share air and get outta Dodge.

Options are even more limited if your buddy is way over there not paying attention to anything but the critter in his viewfinder. A free-flowing regulator can empty a freshly filled cylinder in minutes, and the deeper you go, the faster it drains. Swopping regs and heading to the surface maybe the only course of action open to you. Unless you count reaching BEHIND your head and feathering the valve on your single tank; and turning off your air to fix a free-flow is definitely not something you’d want to try as an emergency as hoc drill anyway. Truth is that without pool practice and at very least a donated octopus (backup reg) attached to your buddy’s tank in your mouth, a sport diver should never turn off his gas.

The simple alternative is to carry a redundant gas source and the most functional and practical for the average single-tank diver is a “pony bottle.”

Time for a not-so-simple definition. Just about everyone who has lounged around the aft-decks of dive boats for a season or two will have heard the term Pony Bottle to describe a variety of small scuba cylinders – all a sort of perfect copy of a full-sized cylinder but looking as though they were put through a hot wash and dry cycle and shrunk – and used for a variety of tasks.

Other names for these mini-cylinders include sling bottles, stage bottles, buddy bottles and a half-dozen or so more equally descriptive names. As with so much that has to do with scuba (for example, what IS the definitive definition of technical diving, these days?) there are few unbendable rules when it comes to words and phrases describing pieces of dive gear. A classic example is a pony bottle. I like to tell people that it can only be used for a small cylinder used as a backup air source… exactly what we are talking about here. Of course, that is not absolutely true, but between us, let’s make it so.

Now let’s assume that we have decided that having a backup source of gas is a good plan, and that the most practical way for us to carry that gas is to use a pony bottle, there are three more questions we need to answer.

The first is how much backup gas is enough?

Well, the short answer is enough to get us back to the surface. But how many litres or cubic feet is enough. Let’s do some basic calcs using an average consumption rate and an ascent speed that will keep our personal dive computers happy as clams. Let’s also pick a depth that is on the fringe of recreational sport diving: 40 metres or about 130 feet.

We start with a gas consumption rate of 15 litres/0.5 cubic feet  per minute. (By the way, the imperial and metric measures use in this example are NOT a direct or exact conversion. Close but rounded for convenience. ) Let’s also say that if we have to “bailout” to our pony bottle at depth, we are going to be a bit freaked out – Murphy does that to divers – and therefore our consumption rate is going to be doubled. So we can use 30 litres or one cubic foot per minute.

Our depth has a direct relationship to the density of the gas we breath so at 5 bar/ata (40 metres or 130 feet), we will use about 150 litres or five cubic feet per minute!

Also, let’s make some allowance for fiddling around at depth for a couple of minutes before we start heading back to the surface. How many minutes exactly is tough to guess, but it would be a mistake to think that we would start to head up immediately we detected a problem and bailed out to our pony. It would be nice to think that’s the way things would unfold but the truth is it takes time to get our buddy’s attention, get ourselves calmed down, sort out our gear and start the swim home. Initially, let’s calculate that we stay at depth for three minutes.

Three minutes at our depth and stress adjusted consumption rate requires 450 litres or 15 cubic feet of gas. (Wow that immediately rules out one of those Barbie-sized tanks doesn’t it?)

Now we can look at the ascent itself. In an emergency, the hard-wired, natural response that kicks in is the aptly-named flight, fight or freeze response. In diving, we have to resist flight, forget about freeze and fight to remain controlled and panic-free. As such, our ascent rate must be unhurried and moderate.  My personal computer is a fourth generation model controlled by a later version of the VPM algorithm, and as such the controlling ascent speed is about 9 metres or 30 feet per minute. Let’s use this speed to get ourselves from 40 metres / 130 feet up to six metres or 20 feet for a five-minute safety stop; which is once again a conservative choice. This gives us a smidge less than a four-minute travel time. We can round up again and make this a full four minutes. (In fact my computer would serve up a variable ascent speed causing us to slow down to about 3 metres or ten feet per minute for the last few metres approaching the safety stop. But we can ignore that in these calculations: and I will explain why later.)

To establish how much gas we will get through during that four-minute swim from depth to the safety stop, we have to know our average depth. The halfway point between 40 metres/130 feet  and six/20 feet  is 23 metres/75 feet  which gives us 3.3 bar/ata. From this we can calculate our gas needs as: 30 litres X 3.3 bar X four minutes;  or 5 cubic feet X 3.3 ata X four minutes. That’s around 400 litres (396 rounded up) or 14 cubic feet (13.2 rounded up).

So far, we need 450 litres at depth and 400 litres to swim to the stop, which adds up to 850 litres. For the imperial crowd the required gas volume is around 30 cubic feet (actually 15 + 14 for 29 cubic feet. A note: if you are doing actual calculations to translate from imperial to SI or metric on the fly, there is some slop in the numbers quoted here because of rounding errors and soft conversion values. The differences though are moot and the principle message remains the same.)

Now we have to spend five minutes at the safety stop. Using our base consumption rate as a guideline, our diver will use around 240 litres or eight cubic feet, and we can round those numbers up to cover the slow ascent from the stop to the surface. (The numbers are 1.6 bar / ata X 5 minutes X 30 litres / 1 cubic foot.)

Looking at our total gas requirements from the bailout at maximum depth then, we have:

450 litres / 15 cubic feet on the bottom; 400 litres / 14 cubic feet for the swim up; 240 litres / 8 cubic feet for the safety stop.  This adds up to 1090 litres (let’s call that 1200) or 37 cubic feet.

Before moving on to touch briefly on some issue that fallout from discovering just how much gas we should think about carrying, let’s make a couple of things clear.

In the calculations used here, we have been conservative with the baseline per minute consumption figure. At least half the divers reading this article would use less than 30 litres or one cubic foot per minute as a working surface rate. However, the other half would probably use more. And by the way, these numbers do work better if you plug in your personal SAC (Surface Air Consumption) and a factor modifying that volume to account for stress based on your abilities and needs, but frankly, our conservative baseline is a REALISTIC average.

Also, we have maintained the “high” per minute consumption rate for the whole of the swim to the safety stop as well as for the safety stop itself. In all likelihood, a diver who has him or herself under control would begin to “breathe easier” as they arrived at a shallower spot in the water column with their circumstances starting to brighten. Using a stressed consumption rate throughout the dive has resulted in a high total gas volume requirement. However, we have not factored ANY gas for a swim back to an ascent line at depth, we have factored nothing in for holdups while ascending, and nothing for blimps in procedures.

We have also opted for a slow ascent followed by a five-minute stop at six metres or 20 feet. We could just as easily have computed a faster ascent speed and a stop at three metres or 10 feet for three minutes. The resulting consumption figure would have been slightly less. However, a controlled normal ascent and a five-minute stop provides a better edge against decompression stress in this scenario I believe.

Finally, we have worked out all these numbers based on a dive at the very fringe of sport diving. A 40-metre or 130 foot dive is the maximum sanctioned for a sport diver with special training. Not all sport dives go this deep. However, in more than 20 years teaching divers about the basics of dive planning, — and being downright lazy –I’ve discovered that using a pinnacle dive (one that’s at the far boundary of what’s best practice for your experience and the maximum for your training) to calculate contingency needs follows perfectly the axiom of calculate once, use many times. In other words, if we follow these guidelines and then bailout from a shallower dive, we should have more than enough gas, all else being equal.

Clearly, the default sized pony bottle would be something that can hold this much gas. A decent choice in my opinion is a 6 litre / 40 cubic foot aluminum bottle. There are a couple of companies making this sized tank and they are relatively easy to find in local shops. Also, this tank has pretty good buoyancy characteristics in the water, is easy to handle, with a little pool practice behind you, and is simple to carry with you in the water.  The important thing is that fully charged, it carries ample gas for the purpose it’s being used for. There is the whole issue about whether to have it piggybacked on one’s main cylinder, carried as a sling bottle (classic North Florida Cave Diver rig) or as a sidemounted bottle (my personal favorite because it is out of the way but accessible), but let’s leave that debate for another article. Instead, let’s look at what type of gas would be the best to carry and why.

The simplest and most straightforward choice would be to always carry in your pony bottle EXACTLY the same gas that you have in your main cylinder. But this does require us to be wary of a potentially fatal mistake. For example, last week, hypothetical diver Jillian was diving a wreck on which an EAN38 was perfectly suitable, and she had her main cylinder and pony filled with a nitrox 38. Everything on her dive was perfect and the pony stayed unused. She does not bother to drain it. This weekend, she and her buddy are going to dive a reef and intend to take a photo of an Elephant Ear Sponge at around 40 metres or 130 feet.  At that depth, her pony bottle mix is hot delivering an oxygen partial pressure of 1.9 bar / ata. This is problematic.

A simple fix is to have the pony filled with a gas that CAN be breathed on a pinnacle dive. For Jillian or for the rest of us non-hypothetical divers for whom the specter of oxygen CNS toxicity is a real one this would be a mix containing 28 percent oxygen, which delivers a ppO2 of 1.4 bar / ata at depth.

The principle of diving with a bailout bottle or redundant gas source is a sound one. Many divers opt to follow the practice. It gives a diver – and that diver’s buddy – options when things go pear-shaped at depth, and allows for a controlled, independent ascent (by which I mean an assent where we are not tethered to our buddy by their octopus).

As with ANY procedure that’s outside the classic stuff taught in most open-water sport programs, there are a few “good to know” knowledge nuggets focused on pony bottles:

1) have the valve and hand wheel within reach, and practice breathing from the reg while feathering the valve.

2) fit the regulator with a full-sized SPG and check it before every dive.

3) pre-breathe the bailout regulator before every dive.

4) drill bailouts often until the process become natural and fluid.

5) mark the cylinder contents and check MOD before every dive.

6) have the hose for the pony bottle second stage long enough to reach your mouth (and your buddy’s)easily. A 40-inch hose is a good start, longer is usually better.

7) at least a couple of times each season, practice a complete ascent breathing from your pony bottle.

8) splurge on a good quality regulator for your pony bottle. It has to perform when you may be under stress.

9) treat your pony bottle system as life-support. Get the components serviced and checked on exactly the same schedule as your main cylinder and reg.

10) NEVER, NEVER, NEVER use the gas volume in your bailout bottle or pony in the gas calculations for a dive. In other words, do not plan your dives around the 1200 litres or 38 cubic feet you have in the pony. That gas is a RESERVE and should be ignored in one’s principle dive plans.

Although not the law, the best general advice for ANY single-tank diver who wants the assurance and personal “cushion” that comes from carrying a pony bottle, is that they  would do well to get some face-to-face time with a good mentor or instructor familiar with the kit and the procedures governing its use.  An excellent certification course on this score is the SDI Solo Diver Certification.

Steve Lewis (doppler@techdivertraining.org) is an active instructor-trainer with TDI/SDI and has written scores of articles on dive safety and skills development and is a regular contributor to several online magazines and discussion groups. He occasionally dives “open-circuit with a single aluminum 80” but never without a pony bottle by his side filled with a lean nitrox. His best-selling book called “the Six Skills and Other Discussions” is available at select dive stores and through onLine stores such as Amazon and Create Space eStore via: https://www.createspace.com/3726246.


“You’ll always miss one hundred percent  of the shots you don’t take.”
Wayne Gretzky, the only NHL player to have his number (99) retired across the league – Born January 26, 1961


With all the postings recently on the scuba forums asking about deep stops and gradient factors, I figured it might be time to get back to some basics. Let’s talk briefly about the five waypoints and ascent behavior, which is a fancy name for a couple of simple ideas designed to help divers manage decompression stress and get out of the water after a dive with all their fingers and toes in place, and all their faculties intact. For the record, decompression stress is something that affects every diver at the end of every dive regardless of what type of dive went before. That said, I believe that for this discussion, it makes most sense to concentrate on the simplest possible ascent: surfacing from sport dives.

In the hope of getting everyone to sing from the same song sheet, let’s define sport dives as dives that require only one decompression stop (sport diving textbooks call this a Safety Stop), and which are conducted no deeper than the common depth limits set by several of the major sport diving certification agencies: 40 metres or 130 feet.

Now, I have to make a small confession, I teach technical diving and I have been teaching students in my classes about Waypoints and Ascent Behavior for more than 14 years. Learning the basic guidelines behind this stuff is a precursor to getting Deco on the Fly squared away. And I include a little module on that as part of my decompression courses. It is easy to learn, helpful and a good mental exercise for folks who want to conduct dives that are deep or long or both.

But it is MORE important to emphasis that the guidelines controlling ascent behavior are NOT only for technical diving; and the five waypoints, which form the underlying structure on which ascent behavior is built, are shared by ALL dives, even sport ones.

Obviously, most sport divers do not need to be bothered by anything outside the stuff covered in their student workbooks. And you will not find anything about Ascent Behavior, The Five Waypoints or anything similar in any of those. Many sport divers are happy – and well-advised – to strap on a Personal Dive Computer (PDC) and follow its directions. However, some of us like to know more than the suggestion “to follow what your computer tells you to do.” For example, if you were one of those kids who took things apart – like the wall clock that Auntie Jane gave your mom and dad for a wedding present – please read on.

The first step is to understand a basic concept, as true in diving as in anything else: when something looks complicated, we can make it look much less threatening by slicing it up into bite-sized pieces.

OK, once we buy into that, let’s apply its logic to the journey from a dive’s maximum depth (or average depth if you want to be more precise) to the surface. This trip can be punctuated by Five Waypoints. And just to restate an important point, these five waypoints work for ALL recreational dives whether they take place in 100 feet or 100 metres. The only differences are that on an ascent from a deep dive, there will be one or more gas switches (from a mix breathed at depth to a gas designed to optimize off-gassing); and the “safety stop” or single decompression stop that is common and recommended for a sport dive, is replaced by two, three or a whole bunch of staged decompression stops ranging from three minutes to many, many times more. All that said, the five fundamental waypoints remain the same!

These are:

1. Planned Maximum Depth or Actual Average Depth

2. Off-Gassing Ceiling

3. First Running Stop

4. Staged Decompression Stop(s)

5. Surface and Surface Interval Time (an often neglected but important part of all dives)

Most technical divers will probably already have an idea what each waypoint is but let’s have a brief explanation for the sport divers reading this.

Number one is simple: how deep did you go or, if you swum a saw-tooth profile, what was your average depth. The second waypoint is trickier to get your head around, but try this for a start. The off-gassing ceiling is a theoretical point in the water column during a diver’s ascent where the net result of the on-gassing and off-gassing meringue that goes in inside a diver’s body, is that more inert gas is coming out of her body than is going in. In other words, the off-gassing ceiling is the point where decompression and true ascent begins. For sport divers doing sport dives to 40 metres or less, we can ballpark this point at a little less than one and a half bar / ata shallower than the average depth. So for a dive to 40 metres or 130 feet on an EAN30 for example, the off-gassing ceiling (or gas transition point) sits at around 25-27 metres or slightly shallower than 85 feet.

Five Waypoints and Ascent BehaviorThe next waypoint – number three – is the first running stop, and at this level of diving, we can fix this at about one bar / ata above our off-gassing ceiling. Once again this is something that the average sport diver may have an issue understanding. I use the term running stop rather than Deep Stop, because I believe Running Stop better describes what goes on in the water column when a diver switches her behavior (ascent speed) to comply with the guideline. For a sport diver, Running stops are not actual stops but rather a change in ascent speed. At the sport level, this translates to the diver rising through the water column at around three metres or 10 feet per minute. Another way to write this is to put a one-minute stop every three metres from the beginning of the running stops until the safety stop is reached. End result is the same… the diver’s ascent has been checked.

The second to last waypoint is the safety stop. I think everyone knows that this is a staged stop of three to five minutes. All I contend is that this is a staged decompression stop by another name and rather than being optional, should be de-rigueur on any dive involving more than a minute on the bottom. Shallower than 30 metres or 100 feet, and well within the NDL, a three-minute stop is fine, deeper or closer to the NDL, stopping for five-minutes makes more sense in my opinion and experience.

The final waypoint is the surface and the surface interval. The SIT is the final stage in a diver’s little gamble with DCS. It is during this time that our diver has to be aware of any strange messages from her body. And it is during this time that she has to prepare herself for her next adventure. In the final analysis, this stage is as important as the rest of her ascent.

OK, those are the Five Waypoints, now let’s take a quick look at how a diver should behave moving from one waypoint to the next. This article is about Ascent Behavior after all!

Here’s the simple pattern for a sport dive. The diver ascends at nine metres or 30 feet per minute but no slower, between waypoints one and two (depth and off-gassing), and nine metres or 30 feet per minute but no faster between waypoints two and three (from off-gassing to first running stop). The diver then moves at three metres or 10 feet per minute between three and four (running stop and safety stop), and once the safety stop is completed (usually at either six metres or three metres (that’s 20 or 10 feet), she will go slowly to the surface no faster than three metres or ten feet per minute.

This is a variable ascent speed: tricky to master but certainly doable for just about ANY competent diver.

What bears thinking about and certainly bringing to everyone’s attention is that following these guidelines, a diver who has finished conducting a 10-minute dive at 39 metres (a smidgen less than 130 feet) will take around 14 minutes to surface! (See illustration. Apologies for imperial users but the conversion to feet is: 39 m = 129 ft; 26 m = 85 feet; 17 m = 55 feet; 3 m = 10 ft.)

A note for the propeller-heads among us who thrive on the nuts and bolts of deco theory: Following these guidelines makes for a slightly slower ascent than all but the most conservative PDC running a dual-phase algorithm. What is key to making this work is understanding that any time spend below the off-gassing ceiling is adding to bottom-time, and that running stops at this level is just a fancy name for slowing one’s ascent to three metres or 10 feet per minute.

Also important is to realize that decompression theory and the algorithms generated by those theories are not grounded in a perfect science. The maths are exquisite. How closely your body and mine follow the tracks laid down by those mathematics is something else more akin to a crap shoot to quote a decompression expert.

Sure, your brand-new fourth-generation PDC is a thing of beauty, has a gaming console and a CPU more powerful and programming more complex than the computers that helped land Neil Armstrong and Buzz Aldrin on the Sea of Tranquility. But decompression theory is just a stab in the statistical dark, and I believe that having an understanding outside of your PDCs user manual — the Five Waypoints and Ascent Behavior for example — is a useful nugget of knowledge. Dive safe folks.

This essay is based on an article that first appeared in Diving Adventure Magazine in 2006. A version was also used as the basis of a chapter in the Six Skills and other discussions called The Deco Curve: Controlled Ascent Behavior and contingency decompression on the fly.

Hi, my name is Bill and I’m here to help…

What exactly does Hogarthian mean?

“Man has such a predilection for systems and abstract deductions that he is ready to distort the truth intentionally, he is ready to deny the evidence of his senses only to justify his logic”

Fyodor Mikhaylovich Dostoyevsky, Russian Novelist: November 11, 1821 – February 9, 1881

Well a whole generation ago, if you were a cave diver hanging out in North Florida, you knew exactly what a Hogarthian rig was. You might not have agreed with it, but you knew who did, and the way they rigged their kit before going for a dive was easily recognized. Crap, you could even dive with the guy who lent his name to the system: William Hogarth Main.

In the interim, what used to be a pretty straightforward definition has become disturbingly fuzzy.

In the overall scheme of things, there’s no big deal in the kind of change that inches closer and closer to clarity, but I’m not a fan of change that moves in the other direction. Accordingly, indulge me today if I whine a little about a good idea gone wonky. Oh, and while we’re at it, let’s try to get a few historical ducks to line up in a row.

Let’s start with the ducks. Bill Hogarth Main is a real guy. Contrary to the views recently expressed in an onLine scuba forum by a newly minted tech diver and self-acclaimed “DIR Practioner” (whatever the heck THAT may be), Bill Main is not some fictional figure created to frighten the meek into conformity. He is just a guy who has been cave diving for a good while and, as far as I know, he still guides at a couple of select caves in North Florida, where he makes his home.

Hogarthian Gear Configuration is named after Bill because it is based on his minimalist approach to kitting up for a dive. Hogarthian has been referred to as the Zen of Cave Diving. Not a bad definition really since the Alpinist Way or Approach to any active, high-stress, high-risk sport is commonly linked to Zen. (I must add that as a Buddhist convert (maybe especially), this coupling is a mystery to me, but let’s leave it alone for the time-being and move on.)

When the concept was introduced to me, the principles seemed VERY straightforward and abundantly clear: Hogarthian kit was simple, serviced, standard, shared, suitable, and streamlined. I can still see my cave instructor standing in front of a white board with those words scrawled on it.

Before we continue, allow me to expand on those points just a smidge.

SIMPLE: nothing convoluted or contrived, and if something can be shaved off, filed down, or trimmed, do so. An example of simple: a piece of kit that can be fixed properly with stuff available from a hardware store. (This was explained to me when discussing dive lights with Bill Main and Lamar English back when I had hair.)

SERVICED: pretty easy to get this one straight. Nothing goes into the water as life-support that is not in working order.

STANDARD: you and the other members of your dive team have agreed on the appropriate kit for your dive and each of you therefore knows the operational niceties (and limits) of those tools.

SHARED: your buddy has your six-o’clock (your arse if you are only familiar with digital time-pieces). This principle can be applied to most of what is taken and what is needed in the water, but the FUNDEMENTAL thing shared is GAS. Tech divers follow gas rules that dictate that a portion of the gas in my tanks belongs to my buddy.

SUITABLE: if you do not need it, do not take it. More importantly, if a piece of kit was never intended or designed to cope with the environment you are going to take it into, resist the urge to push its functional envelope.

STREAMLINED: now this should come as no surprise to anyone who has read a book on technical diving. Short version: do not look like a Christmas tree, get rid of danglies, and aim for minimal resistance when swimming. I was once called on this score by Bill Main for wearing a drysuit to go cave diving… wow, that really is a shocker, isn’t it?

At some point, the definition Hogarthian got high-jacked and people started to apply it to kit choices and configurations that were many zip-codes away from what started out as a good idea. There is certainly nothing wrong with progress, and smart innovations in industrial design, electronic engineering, and materials manufacturing have made fools out of many of us who said: “I’ll never do that!” But I am not sure that moving away from the six basics that originally defined Hogarthian Configuration constitutes good thinking or best practice.

Those six guidelines actually hold true as much today as they did in the 1980s and early 90s when they were developed. As a CCR and OC sidemount cave diver I plead forgiveness for some of the choices I make, but I like to think that my diving philosophy is supported by those six “S” words.

Certainly when I look at divers who have adopted the more or less standard North Florida Cave Diver’s Kit consisting of back-mounted doubles, isolation manifold, wing/backplate, long-hose, bungeed backup, and a drysuit, the vestiges of Bill Main’s ideas are there… under the surface in some cases but the smell and taste remain.

What disturbs me though is that as functional as this layout has been, and how ubiquitous it has become in the technical diving community the world over, it is neither a perfect solution, nor does it conform to several of the basic tenets of Hogarth’s “Zen Outlook.”

Certainly to label it as “Right” or the best option available confronts the one principle of Hogarthian configuration that I neglected to add to the list above. I saved it until last because I feel it is the most important and deserves to be here at the end.

And frankly, without it, all the rest falls apart. What is it? Just this: Constant focus on improving the system, because nothing is perfect.

Thanks for your attention. History lesson over.

Accident Analysis (take two)

Enroll in any high-risk, high-stress endeavor, and the chances are that one of the first topics your instructor will throw into his or her opening conversations with you is how many ways you can kill or hurt yourself doing what it is you just signed up for. The first steps in just about every training program in the “adventure” category of things to do – from flying a plane to shooting a gun (at targets or bad guys) or climbing rocks or heli-skiing – will walk the activity’s newcomers through potential pratfalls. It’s a kind of universal mantra: learn from the mistakes of others.

Diving courses, well, certainly ones aimed at imparting skills for technical diving, work in a similar way. The politically-correct term used in the industry is Accident Analysis, and the framework for the AA modules I have been taught, worked with, or developed and written over the years follows closely the one first constructed and then refined for teaching cave diving. In its shortest form, an Accident Analysis module boils down to three stages: here’s some advice about what works, here are some examples of people ignoring that advice, now can we agree that they were stupid and that we will try not to follow their example.

For the record, here are three real-life scenarios that got people killed. I share these with tech students. See what you make of them.

Scenario one: August, 2009. Three experienced sport divers attempted a deep dive off the coast of California. The participants were a dive-store owner, his friend, and a 22 year-old shop employee and DM. Although the trio had done similar dives before, none was certified beyond sport-diving limits. The dive shop involved did run tech programs, but they were overseen by a third-party instructor. Worth noting is that this individual was NOT part of planning the dive in question and was apparently not involved at all. By the way, the dive was planned to be around 60 – 65 metres using air as back-gas. It turned out that the actual dive’s depth exceeded the plan at 70 metres plus. During ascent, the “team” lost contact with each other and the 22 year-old man was seen drifting away from his dive “buddies” and was sinking. After some time, his body was found on the surface.

Scenario two: November 2009. Two divers attempted to dive Eagles Nest on CCRs. On a previous occasion, the pair had been taken to the “cavern” area of the nest by an instructor teaching them a course on CCR which they did not pass. For the record, one must apply a very liberal definition of Cavern to describe any part of the entrance to Eagles Nest, an extensive and very deep (80 metres plus) cave in Hernando County, Florida. Also for the record, neither man was cave certified, nor was the instructor who had previously taken them to the cave for training dives, a cave instructor. During their ill-fated final dive together, the two CCR divers had opted to use a diluent in their rebreathers was hot for the depth they attained (reportedly one containing 18 percent oxygen). If this were the case, it would have made impossible at depth controlling their setpoint (partial pressure of oxygen) at recommended levels of 1.2 or 1.3. Also, a meaningful diluent flush, cell test would have been impossible. At some point, approximately 170 metres from the cave’s entrance area, one of the divers experienced difficulty and died. His body was recovered in one of the deepest sections of the cave some time later by a team experienced in deep-water body recovery.

Scenario three: In mid-November 2008, the bodies of two divers were recovered from Wayne’s World (aka School Sink), Pasco County, Hudson, Florida. Wayne’s World is considered an advanced cave dive yet only one of the buddies had ANY overhead training, and that was only an Intro-to-Cave card – well shy of what’s recommended to dive this site. The other diver carried only an Advanced Open Water certification. Both were wearing traditional North Florida Cave Kit with decompression gas. Recovery divers discovered both bodies within 80-90 metres of the cave entrance. Their bodies were separated by approximately 30 metres distance. One was found at a depth of approximately 14 metres with his oxygen decompression gas deployed (oxygen is considered highly toxic if breathed deeper than around 6 metres). The other was deeper in the cave, dead on the ceiling showing signs of distress. During inventory of the dead divers’ equipment, this diver was found to have his isolator closed with one cylinder empty and the other containing at least 3500 psi.

Here are the questions I use to begin the analysis process in the classroom.
Where did logic chain begin to break down?
What simple guidelines seem to have been ignored in these cases, and how might ignoring them have contributed to the seriousness of the situation these people found themselves in?
In all three cases outlined, whom do you feel should shoulder some responsibility for these deaths?


Of course, by its nature, this exercise is speculative since the process asks us to form conclusions based on a sandwich made from a couple of slabs of conjecture and a thin layer of fact. There is also a complex moral issue with us forming a judgment about someone’s behavior – which inevitably happens – without their input during our deliberations. After all, there may be rectitude in their behavior – although on that last point, experience does tend to suggest there are no fixes for stupidity.


However, all that aside, the exercise serves a purpose which is not to allot blame but rather to identify errors, understand how easy it is to mess up and from that deductive analysis, avoid repeating the same mistakes ourselves.

There’s one other shortcoming. Between you and me, I dislike using the word Accident to describe many of the examples we use to point out the kind of behavior that results in diver deaths.

What is an accident?
One definition of an accident is “any unplanned event that resulted in injury or ill health of people, or damage or loss to property, plant, materials or the environment or a loss of business opportunity”.
That’s OK as far as it goes. Certainly unplanned seems to be the pivotal point, but it begs some further investigation… and definition surely. Let’s take for an example scenario three above.
It’s well known that diving in a cave without training is a poor choice. Did the two guys who died know that diving without training, experience and kit in a cave was a poor choice? Sure they did. There’s a bloody great big sign to remind them at the cave entrance. They planned to dive ignoring that fact, and I’d wager the general consensus from fellow divers would agree as inappropriate using a definition that includes the term “an unplanned event” to describe their actions.
Given the circumstances of their dive, their behavior was risky: they took a risk and their calculations – whether conscious or not as to how likely their choice was to backfire and kill them – was incorrect. They screwed up, assuming naturally that their intention was not to kill themselves. Think about this: One guy had around half his back-gas available. All he had to do was switch regs or reach back and check his isolator. Yet signs at the site of his death indicated he drowned.
Is deciding to take a risk and miscalculating its inevitability an accident? Is ramming into the back of a parked car at high-speed with an alcohol level above the legal limit for a driver – whatever that limit may be – an accident? Surely it’s recklessness, carelessness or criminal. What do you think?
The Brits use the term “death by misadventure.” For the record, the definition of this phrase in Webster’s is “a death due to unintentional accident without any violation of law or criminal negligence. Thus, there is no crime.”
Death by misadventure does have a nice ring to it: no blame, just a couple of guys out on a lark that went wrong. Is that how you see scenario two, or is there more to it.? Is there some level of culpability, negligence?
A buddy of mine tells his students that cave diving is deceptively easy.

“Anyone can swim to the back of a cave,” he says. Another buddy tells his students that “Even an open-water diver can make a dive to 60 or 70 metres.” They also add that their statements are only true until something goes wrong. In a pear-shaped world, it’s finding the way out from the back of a cave or getting back to the surface intact from 20 storeys down that presents problems.


When things go wrong underwater, the fundamental skill becomes survival. In diver training, this is broken down into three major tasks:
• control the natural fight or flight (or freeze) response
• suppress panic
• work on getting your ass back home (This latter skill requires critical decision-making, physical and mental actions involving some level of multi tasking, which some people can do, and some cannot.)
The ability to react appropriately when things fall apart is an acquired skill even for those who have some natural abilities and the skills to survive. It takes knowledge backed up by experience and practice. How much of each is a hugely debatable point, but I believe the diving community as a whole agrees that it takes more experience and practice than one can gain during the average technical diving class… even when full knowledge of what to do and how to handle the situation has been taught.
Well, that’s a shocker, isn’t it? We certify divers to do dives but we believe they may need more experience and practice before they can survive something going pear-shaped!
If this were the case, our beaches would be littered with the dead and injured and clearly they are not. Most people leave a dive class – regardless of whether it is a sport diving or tech diving class – with a full understanding that what they just earned is an OK to go out into the real world and gain experience and practice, gradually. They have the knowledge to do so well within the limits of their training. And that is the key… within the limits of their training. Without training or with a disregard of what that training taught, all bets are off. They have no knowledge and are unlikely to live long enough to gain wisdom.
So what is the bottom line, take-home message from Accident Analysis?
I’ve always reckoned it to be the advice to take things slowly, to be cautious, and to stay within the boundaries of your comfort zone, which are the actions of a wise diver. What does Accident Analysis say to you?

Zero-to-Hero… there are no winners in training shortcuts

If all you can think of when you read the phrase “Zero to Hero” is a British post-punk band, hats off to yer! However, chances are that as a diver, the phrase has other connotations: far less entertaining.

I really have no clue where and when the Zero-to-Hero epithet was first applied to diving. I heard it around the time that the whole concept of technical diving and especially technical diver training began to enter mainstream dive-community awareness, sometime in the early to mid 1990s. At that time, Zero-to-Hero was applied specifically divers who miraculously leapfrogged from newbie to expert seemingly overnight.

It worked like this: a small core of instructors and dive shops started to advertize “boot camps” that promised punters some form of guaranteed certification at the end of a week or so of “intense training.”

An example from that time was a seven-day “mega-course” that swept candidates – advanced open-water divers who carried no technical certifications or experience — to trimix certification by the time the circus wrapped up. (For the record, this meant guaranteed certification to conduct full decompression dives on helium mixes with exposure up to 60 metres deep.) I believe the prerequisites to sign-up for these programs included having a pulse, a checkbook, and a broad gullible streak.

Gullibility? Well, at issue was the obvious. If one looked closely at some agency standards, it was just about possible to cram into a seven-day period, the required classroom, confined water and open water dives. Possible yes, but far from desirable… and certainly could not possibly carry any guarantee that participants would have earned their certifications at the end of it.

From a training agency perspective, this type of course barely met the letter of the law, and certainly bent the spirit of it into the shape of a banana. What was missing from the equation was experience. The poor punter would find himself or herself dragged into progressively more complex dives  day after day without any time to catch their breath or reflect on the lessons to be learned. They would be taken at lightning speed with little time to ask questions – or more importantly, discover answers – as they progressed rapidly from a normal dive plan that consisted of a quick “Let’s go diving…” to something that would help protect them and give them the tools to ascend from water deep enough to cover a 20-storey high-rise.

At the end of their “intensive training” they would have completed a handful of staged decompression dives under the auspices of an instructor –and auspices is about as apt a term as possible to describe what would have been going on for seven days. Unfortunately, playing follow-the-leader on what was essentially a guided, trust-me dive does not constitute technical diver training.

The certifying instructor’s crime – if functioning without a moral compass can be classified as such – was that when all was said and done, they handed out cards which stated the holders were capable of doing the same dives at some future date without the help of a baby-sitter.

I worked on the Training Advisory Panel of a large agency at the time and, like many of my peers, felt there was something wrong with that. Apparently, we were not alone, and to my knowledge, the temptation to promote this sort of fast-track program for John and Jill Diver was pistol-whipped out of the rank and file tech instructors by many of the major, reputable tech agencies. In addition, the market, divers who were expected to buy-into the concept, quickly realized that Zero-to-Hero type training was not a sound investment. Today, this fast-track practice has fallen out of favor in the tech arena: or has it?

One of the companies for whom I do consulting work, makes rebreathers: the fully closed-circuit kind. The data suggests they are the market leader world-wide… or very close to it. Certainly their brand is well-known and highly visible in the technical market.

Rebreathers are tech, correct?

Well, the dive industry is nothing if not dynamic and that’s changing. Several manufacturers – including the one I work with – are in the middle of readying themselves for a minor market tremor that promises to open rebreather diving up to sport divers.

Given a couple of provisos, I do not believe there is any real problem with that. Diving rebreathers is fun, and with real prerequisites met and enough time for practical work, a sport-diver CCR course will probably work. It will be hard work for everyone involved, but not impossible to organize and probably a whole lot of fun to deliver!

Provisos met.

The only thing that bothers me a little is that this new market opportunity – and that’s how it’s being billed within the professional segment of the dive industry – feels like an opening for the Zero-to-Hero can of worms to open up all over again. Only this time, it’s not the punters I worry about… it’s the instructors who will be delivering their training.

Most CCR manufactures have a unique power when it comes to who teaches on their units. You might think of it as a special veto. An instructor candidate (regardless of if their agency believes them ready to teach) has to be given the OK to conduct training classes by the manufacturer of the unit he or she wishes to teach on. Part of the minimum prerequisites held to by the major rebreather companies is that the instructor candidate must have logged 100 hours on the unit.

There is nothing magical about 100 hours experience flying a CCR; except it takes a while to accumulate. Also, although it does not guarantee much, it is highly likely that during the accumulation of AT LEAST 100 logged hours in the water, the majority of divers will have learned some important lessons about their unit and themselves.

CCRs work just fine… at least the two I dive seem to… but all rebreathers are unforgiving of sloppy procedure and short-cuts. Most divers will experience one – sometimes more than one – “come to Jesus” moment during 100 hours of operation. The most essential lesson they will learn is not that their unit malfunctioned, but that they dropped a stitch and the culprit is HUMAN ERROR. They will develop a visceral understanding that they were at fault.

You can read all about human error and lack of situational awareness in a book – damn, I’ve written about it myself – but the words tend to leap out of your memory and grab you around the throat when you are at 60 metres and recall that you did not do a thorough pre-dive check: and that gurgling sound is not because the rebreather was designed incorrectly. Operator error is a great teacher, and a very fine learning tool.

So, what’s the problem? Simple, really. We can expect a lot of interest in rebreather training during the next few years as this whole Sport Diver Rebreather thing hits the market, and there is going to be a temptation for instructors to “get in on the action.” I have already heard instructors selling the concept to their students. However, few of them have any experience diving rebreathers, and more to the point, do not seem to comprehend that a rebreather is unlike any piece of open-circuit kit and no amount of time on open-circuit translates to running a CCR life-support system. My fear is that some instructors may fudge their logbooks in order to attain instructor status in the shortest time possible. There are some checks and balances in place, but there are ways to cheat them too.

I may be alarmist and all this concern may be unfounded. But please, if you or someone you care for is thinking about making the switch to a rebreather, be very, very careful that you avoid any whiff of Zero-to-Hero in your instructor: regardless of the agency they teach for or the unit they teach on.

Cardiac Stress Testing and technical diving

Around this time every year, most of us hang up a new calendar, and polish up the New Year’s Resolutions. Like me, you probably have a few left over from last January 1. If you do, chances are good that one revolves around “getting fitter,” “getting in better shape,” or “working off all that Christmas pudding.” If that is the case, and you’re a diver, I’d like to suggest adding a slightly different twist for 2012.

During a few recent and very informal discussions with other tech instructors, one of the highest-ranking concerns has been the number of divers – particularly tech and rebreather divers – who have died of heart-related problems either while diving or soon after diving.

There are all kinds of issues that may have had an influence on incidents in the past, but the collective concern was how to help make 2012 a “better year” for the dive community.

One idea floated out was to ask students* to undergo a cardiac stress test as part of the list of prerequisites that need to be met before enrolling in advanced technical programs, such as CCR, trimix and advanced wreck and cave.

A cardiac stress test stimulates the heart – either by exercise or with intravenous pharmacological stimulation – and connecting the testee to an ECG. The American Heart Association recommends this kind of testing for patients with medium risk of coronary heart disease. This includes folks with personal risk factors such as smoking, a family history of coronary artery stenosis, people with hypertension, and folks dealing with diabetes and high cholesterol.

Who knows if it would make much of a difference, but what harm would it do? I’m old and get one for free every year through my insurance (BONUS!), and there is a level of comfort knowing that there are no serious issues with the old ticker.

I believe the cost of a cardiac stress test works out to about the same as the charter fees and fill costs for an open-circuit deep wreck dive. Worth the dough? I think so and certainly worth adding to that list of resolutions… Things to do in 2012!

* Students who have risk factors, or those 45 years and older.

Helitrox Decompression… class notes

What you need to know about Helium
(a supplement for techdiverTraining Helitrox divers)

As a Helitrox Decompression Diver, there are a few things you should know about helium, this new gas you can now add to your scuba tanks, since your TDI decompression procedures textbook does not cover this topic at all. Luckily, the vital stuff – the things you need to know to help keep you happy – can be summed up in a couple of pages. Please read on!

We can start off by looking at some of helium’s properties.

Anyone who has organized a kid’s birthday party and bought party balloons already knows helium gas is lighter than air: it’s actually many times lighter than air. For those with an interest in these things, a mole of helium has a mass of 4 grams compared to 32 grams for the same quantity of oxygen and 28 grams for the same amount of nitrogen.

Just in case you forget your high-school science, a mole is measurement of quantity – a specific number of elemental particles or molecules – used in chemistry. For example, a mole of Ideal Gas has a volume of close to 22.4 litres at STP (Standard Temperature and Pressure – 0 degrees Celsius, and one atmosphere or 101.2 kPa). An ideal gas is defined as a hypothetical gas in which all collisions between atoms and/or molecules are perfectly elastic and in which there are no intermolecular attractive forces. This is unrealistic behavior for a gas but we use it in diving because diving is not an exact science. In the context of diving, we can say that 22 litres of helium weighs 4 grams compared to around 29 grams for 22 litres of air.

Is any of this really vital to you as a Helitrox Decompression Diver? Nah, not really. However, it does help to show us why a cylinder filled with trimix, has buoyancy characteristics that are different to the same cylinder filled with air or oxygen: it has a tendency to float, the oxygen cylinder does not.

One other issue that relates directly to the mass of helium is work of breathing (WOB). The deeper we dive, the denser our breathing gas becomes and pulling a lung-full of gas into our body requires more work and effort. Using air or nitrox, you may have already noticed that your regulator – which performs perfectly at 20 or 30 metres – starts to feel a little “tighter” as you venture past 40 metres (132 feet). The WOB, even on a well-adjusted, high-performance regulator, increases noticeably as we descend deeper than 60 metres (200 feet). This increased workload can play a major role in carbon dioxide build-up in a diver’s blood, which of course affects respiratory function.

In short, gas density affects a diver’s comfort, safety and performance. Adding helium to our bottom gas effectively thins out that gas making it easier to breathe at depth. With 20 percent helium in your back gas, you may notice your regs have never breathed easier!

Back to our high-school chemistry for a moment: Helium is a member of a handful of elements known as Noble Gases. The term “noble” probably comes from the fact that these gases have their outer electron shell completely filled, and this makes them (Helium, Neon, Argon, Krypton, Xenon, and Radon) “aloof” and in most circumstance, nonreactive or inert. Noble gases do not bond with other elements. Helium is pretty typical in that it does not burn, does not mix with other substances to form stable compounds, and – as with its noble gas bunkmates – is monoatomic; in other words, it does not even like to associate with itself and hence we write ‘He’ and not ‘He2‘ as we do with O2 and N2. The behavior of helium as a Noble Gas is only a concern to us as divers when we need to make exact calculations to mix gases accurately. Coles Notes version: for a given pressure and temperature, one gets less He in a scuba cylinder (fewer moles) than air or oxygen (i.e. 200 bar of helium is NOT the same as 200 bar of oxygen).

OK, so notwithstanding the all of the points outlined above, one basic question remains: Why do we use helium? I am not trivializing the importance of floaty bottles, lessened WOB at depth and how many moles we can cram into an aluminum “80”, but what else is there to know?

Probably number one is that helium is – for the purposes of diving at depths attained by recreational technical divers – biologically inert. Since it is not narcotic and non-toxic, it makes a great diluent for nitrogen and for oxygen. Adding helium to keep the partial pressures of both those gases to manageable levels is the real reason for this course. Your classroom notes should include the basic “Dalton’s Law” calculations for the suggested bottom-gas mix to be used on the pinnacle dive for this course… a 30 minute exposure at 45 metres (150 feet).

Just in case you do not have those notes handy, here is the short-form:

Ambient pressure at depth of 45 metres = 5.5 bar

Target Oxygen Partial Pressure at depth = 1.30 bar

Target Nitrogen Partial Pressure at depth = 3.16 bar (same as air at 30 metres)

Vacant partial pressure (Ambient – (O2 + N2) = 5.5 – (1.3 + 3.16) = 5.5 – 4.46 = 1.04

So, we have to fill 1.04 bar with something other than oxygen or nitrogen to keep the levels of those two gases within a tolerable range. Easy, we can use helium because it is a “diver-friendly” gas.

Now, at some point, we have to let someone at a dive shop know what flavor of trimix (or Helitrox) we want them to mix, and so we need to convert partial pressures in bar to a percentage of the ambient pressure. In other words, we need to calculate the ratios of each of the gases used.

Here are those calculations: 1.3/5.5 x 100 = 23.6% Oxygen; 1.04/5.5 x 100 = 18.9% Helium; 3.16/5.5 x 100 = 57.4% Nitrogen (rounded numbers which do not quite add up to 100%).

I am not sure what the folks are like where you buy your fills, but I could not bring myself to ask my supplier for a mix with fractions such as 23.6 or 18.9. It makes more sense to round the numbers up to whole numbers, let’s say a 23/20, and that is what I would dive. For the record, TDI suggests the mix for this class at this depth cannot exceed a 25/20. I cut back on the oxygen pressure just a little because I believe it better suits the water conditions where I do most of my diving.

OK, just two more small issues to deal with. The first is perhaps the biggest myth surrounding dives using trimix. The myth is that ANY mix with helium is going to give a diver a much longer decompression obligation that diving air. This is patent bullshit. I simply cannot categorize it any other way.

Helium is said to have faster transit times than nitrogen in a diver’s body; it is absorbed and eliminated more rapidly than nitrogen. This does result in ascent schedules with a slightly deeper off-gassing ceiling, calling for running stops beginning deeper in the water column, but overall ascent times are shorter NOT longer. Here is an example that’s relevant to the type of diving you will do as part of the graduation requirements to earn certification.

A dive to 45 metres for 30 minutes breathing a 23/20 trimix and a EAN50 starting at 21 metres on the way up. Total runtime = 63 minutes.

Exactly the same parameters for the dive but substituting air for the trimix on the bottom and keeping the EAN50 deco gas for the ascent. Total runtime = 74 minutes!

OK, so perhaps there’s a difference because the trimix has 23% oxygen and air only has 21%. Here the same dive with an EAN23 instead of trimix and all the other stuff the same. Total runtime = 71 minutes.

No matter how you cut it, the ascent time on trimix is shorter. (By the way, the first running stop on the trimix ascent IS deeper by about three metres.)

OK, so with that myth busted, let’s move on. The final item is thermal stress and the role of helium in hyperthermia. Helium does a poor job of insulation and pure helium would make a very bad inflation gas for a diver’s drysuit. I have dived in a cave in 20-21 degree water using pure helium in my suit. It was not a wonderful experience: I strongly suggest you do not try it for yourself.

TDI suggests using an alternative suit inflation system to one’s back-gas when ANY helium is being used. This is a great idea if you are diving in an area with a marked thermocline; however, many divers diving in water 20 degrees and above, find very little thermal effect when using a gas with only a moderate amount of helium in it. During this course, you should not have more than one-fifth of your back-gas given over to helium. You may find it unnecessary to carry a separate drysuit inflation system in moderate to warm water conditions.

Oh, one last thing, sound travels about four times faster in helium than in air. One result of breathing helium is that it makes one’s voice sound like Donald Duck or Minnie Mouse. This Disney effect is really funny. However, be aware that pure helium or helium mixes that do not contain at least 21 percent oxygen, are dangerous and breathing them may result in hypoxia and death or serious brain damage. Keep helium away from kids!

Thanks for your attention.

Steve Lewis

TDI instructor-trainer

Omitted Decompression and In-water Recompression (IWR)… some thoughts

Occasionally, in fact with an almost predictably cyclic regularity, two questions that surface on the internet dive forums ask about missed decompression and/or in-water recompression (IWR).

My standard answer on a public forum is to suggest that when the diver shows signs or complains of DCS symptoms, notifying EMS, keep the diver on the surface, warm and hydrated, monitor for changes in their condition (a correctly conducted five-minute neurological exam is a decent protocol for this), have them breathe pure oxygen (preferably from a demand face mask), take notes that will be useful for EMS/Hyperbaric staff, and prepare for fast evac.

The suggested strategy for a diver who has omitted a “deco stop” or safety stop but is SHOWING NO SIGNS or who is NOT COMPLAINING OF ANY SYMPTOMS, is the same as above but without the call to EMS and rather than preparing for evac., collecting their kit for them and keeping them out of the water for at least 24 hours.

However, neither is a very good answer to the actual questions posed, and occasionally, I throw my hat in the ring… something like this.

The first step for anyone brave enough to attempt an answer is to define the differences between the two topics; and in particular, the circumstances that might necessitate the call for a diver to conduct an omitted decompression protocol, as opposed to those that indicate IWR as an option.

Let’s start with the easiest: Omitted Decompression.

The protocols for Omitted Deco are discussed and outlined in several technical diving student manuals – including a couple of TDI manuals – and the procedure is taught as part of TDI’s decompression and trimix courses. It is based on the protocol published in the US Navy Diving Manual and may only be attempted when the diver shows NO SIGNS and has no SYMPTOMS of DCS; and the omitted stop was no deeper than six metres.

There are a couple of other prerequisites relating to water conditions, weather conditions, thermal protection, available gases in sufficient volume, having a tender diver available to monitor the subject diver during the whole procedure, and the diver being in a position to return to the water within five minutes of surfacing.

All that as taken and confirmed: First, return to 12 metres and conduct the stop required at that depth by the original ascent schedule PLUS one quarter of the omitted three-metre stop time. If no stop was originally required, remain there for one quarter of the omitted three-metre stop time. Ascend to nine metres at a speed no greater than three metres per minute (the ascent speed for the whole procedure) and remain there for one third of the three-metre stop time. Ascend to six metres and wait there for half of the three-metre stop time. And finally ascend to three metres for one-and-a-half times the scheduled three-metre time.

Here’s the way that looks for an omitted or partially omitted deco stop at three-metres.

Depth (metres/feet) Original Stop (mins)/Gas Omitted Stop Procedure
12 metres/40 feet None/ bottom gas 3-minute stop
9 metres/30 feet 3 / bottom gas 4-minute stop
6 metres/20 feet 5 / oxygen 6-minute stop on oxygen if CNS allows
3 metres/10 feet 12 /oxygen (omitted) 18-minute stop on oxygen if CNS allows

For the record, I have tendered for divers who have missed all or part of a decompression schedule and for whom the missed deco protocol worked.

Now let’s attempt to clarify the issue of IWR. This is suggested when a diver surfaces and complains of symptoms (type one) and IWR is the ONLY option available… i.e. there is no hope of stabilizing them and getting them to a hyperbaric facility.

Important to establish first off that this is a highly risky endeavor. The risks of IWR include several minor issues relating to thermal stress and volume of gases needed, but the strong emphasis in the entire risk assessment analysis center on the subject diver getting worse far worse once in the water and becoming, for example, paralyzed and/or losing consciousness. Oh, and then dying.

Various protocols and tables for IWR have been developed over the years. The recognized tables include the Australian, the Hawaiian, the US Navy, and the Pyle tables… I believe Pyle’s modification to the Hawaiian table are the most “up-to-date.” I am reasonably sure that NONE carries sanction from the major sport agencies. The technical agency I teach for, that I do consultant work for, and on whose training advisory panel I served for several years, does not sanction IWR either. Essentially, within the context of recreational diving (tech or sport), IWR is simply NOT an option.

Just in case we wonder why, here’s a checklist of the minimum kit and personnel requirements for attempting IWR in a remote location.

  • A heavily weighted shot line secured in a sheltered spot where surface waves will not influence comfort of subject diver and/or the tender (who will be in the water) and treatment supervisor (who will be on the surface).
  • Some way to hold the subject diver in place… a climbing harness works as does a sidemount harness with some modifications
  • Stages in the shot line to hold the subject diver at a set position in the water column… prussik loops and a locking carabiner work if tied and anchored correctly.
  • Full-face masks with coms to the surface and each other
  • Surface supplied gas (oxygen et al) supplied to the subject diver via umbilical
  • An experienced tender and supervisor who have at very least certification and some background in hyperbaric treatment
  • Adequate and possibly additional thermal protection for both subject diver and tender
  • A valid IWR treatment “table”

As someone who is occasionally involved in expedition diving (the only situation I can imagine where the whole team would discuss IWR as part of the SOPs during pre-trip planning sessions), IWR is considered highly risky even when ALL the above, and a few more details, are available. It is also understood that IWR (just as recompression in a chamber on the deck of a boat or in a medical facility) may not resolve the issue. In other words, the subject diver may die.

The preferred option if a portable chamber is NOT AVAILABLE – and something many expedition leaders seem to have less hesitation using – is saline IV (intravenous) therapy, oxygen and the use of pain medication all administered by a practicing medical practitioner of some sort… NP, Paramedic, MD et al. It is therefore considered best practice to have at least one of these as part of the team on ALL expeditions to remote locations.

(For the record, I have been lucky enough to lead several expeditions to various spots where there may have been a temptation to use IWR, and I have certainly tried to make sure that at least one team member is an experienced diving MD. To date, one of my team has had to supervise an autopsy on one of our fellow team members, but we have not had to deal with IWR. Therefore, my first-hand experience in this issue has been ZERO.

You can read more at Gene Hobbs excellent online resource:


CCR Cave… special circumstances or a walk in the park?

Following on from one of the main debate streams that surfaced during the NACD conference, a few buddies and I recently discussed the “deliverables” of a CCR Cave Diving course.

One of them — and it seems a valid topic to present to “new” CCR cave divers as well as experienced OC cave divers signed up for a cave orientation course — is gas volume management for bailout scenarios.

Typically, OC cave divers have a pretty simple set of rules to govern how much gas they need to carry with them. For CCR divers, those rules are not as simple because there is an extra variable. And that variable is the diver’s gas consumption rate once he has bailed out: it will vary a lot!

To better understand that why this is, we have to consider the reasons that would drive a CCR diver to abandon “the loop” to breathe open-circuit.

One example — perhaps the worse-case scenario — is carbon dioxide poisoning. There are a bunch of possible events that could lead up to this, but for the time-being, let’s just take it as read that the diver has experienced one almighty pear-shaped CO2 breakthrough event, and has ALMOST left it until too late before bailing out. He is hyperventilating and is close to panic.

So, what consumption rate is best to use as a benchmark?

For most to the OC stuff I teach — and in lieu of real data — a SAC rate of 14 litres per minute is a good starting point. (That’s about half a cubic foot for those struggling with imperial units.) To find the actual consumption (RMV), that number would be multiplied by the depth or average depth expressed in bar and the product of that calculation by a number to represent the Dive Factor (workload, thermal stress, etc.). For most OC dives, a DF of 1.5 to 2 is OK. However, for a CCR diver battling back from the edge of CO2 oblivion, a DF of 3 is the minimum recommended stating point.

To put this into a real-world example, consider a CCR diver bailing out around a 40 minute swim from the mouth of a cave with an average depth of 25 metres.

Our 14 litre per minute consumption rate now gives us 14 X 3.5 (depth in bar) x 3 (DF) X40 (minutes to surface) which equals 5880 litres.

That is a lot of gas, and effectively requires the diver to carry more than two fully-charged 12 litre cylinders (aluminum 80s) as bailout. Is this realistic? Is it realistic to imagine that the elevated consumption rate experienced immediately following CO2 break-through would persist for the full duration of the exit swim? Also, is it wise for the diver to have no redundancy in the event of one of those two bailout regulators malfunctioning?

What do you think?

View from a different vantage point

The gentle slope that stands between our sugar bush and the raised beds we use to grow veggies, is covered in white trilliums. Fact is the whole wooded area behind our house and down into the small valley that forms the southern boundary of our property is full of trilliums and trout lilies in early spring.

This indicates that our little corner of Muskoka is waking up from winter, finally, and is taking on the postcard picture beauty it is famous for at this time of year. Fittingly, white trillium is the provincial emblem of Ontario – where I live – and, just for the record, is also the state wild flower of Ohio. So my guess is that a lot of folks agree that trilliums are neat little flowers.

Usually I am not home to see them bloom. Most years I am away someplace diving, but this year is different; I am “on sick leave.” In the simplest terms this is a bummer.

On the upside of this situation, I uncharacteristically have the time to sit on the sidelines as spring arrives here in full force. And in between watching eastern bluebirds and tree swallows battle it out for nesting boxes, celebrating the early appearance of Ruby-throated hummingbirds, avoiding the attendant black fly hatching, and taking notes on the ongoing procession of wild-flower bloomings, I have had some time to reflect on what I do for a living:  teach and write about technical diving.

My forced inactivity is the result of an unfortunate early April convergence of two seemingly unrelated issues.

One is a result of back pain mentioned in an earlier blog, and the other being an unfortunate run-in with Epstein-Barr virus. Epstein-Barr is a nasty illness that goes by the common, rather insipid and nondescript, name of Mono. It is a rotten punishment for anyone, but especially so for those of us with an A-type personality.

My strategy for dealing with the first is corrective posture, yoga and physiotherapy, and to kiss goodbye to doubles and the ubiquitous North Florida Cave Diver’s Rig.

No more diving doubles for Doppler. After about 20 years of abusing my body marching around with the equivalent weight of a corps de ballet dancer strapped to my back, the spokesperson for my thoracic vertebrae has told me directly and unequivocally that it is time to concentrate on CCR and Sidemount.

The second insult to my well-being is not as easy to fix.

In fact, it promises to be a juggling act. But time and patience will win out. In the meanwhile, now that sitting at my desk and typing does not hurt, it’s time to share what’s next on my, to do list. It no secret to anyone involved in technical diving, that in the past decade or so, the limits of our sport have shifted outwards a fair bit.

New technology, gear designed specifically for extreme diving, a freely available database of ascent profiles that worked, a growing network of instructors willing and able to mentor interested divers, discussion forums et al, have all contributed in some way, minor and major, to this movement.

For example, ten years ago, there were few recreational divers who had visited 100 metres; in 2011 non-military, non-commercial, non-scientific divers around the world pull off 100 metre dives weekly if not daily.

Ten years ago, only the most experienced attempted a cave dive to the end of the gold-line in one of the “tourist caves” in North Florida, or a weekend charter to a 350 foot-plus dive site. These dives earned a mix of admiration and admonition. In 2011, we read about relatively new tech divers doing these dives and hardly anybody notices… or so it seems.

The odd thing, at least to me, is that so few dive teams employ in-water support divers to help make these deep, long dives a little more managed. Perhaps we need to do something about that situation.

Over the course of the next couple of weeks, I want to lay out some ideas I have for a new book specifically aimed at teaching and discussing roles and techniques for expedition support; because I can’t do much in the way of diving!I would appreciate your input. As much as I like looking out at the new season arrive, it is driving me nuts!

By the way, would appreciate your input on a small survey… You will find it here>>>DIVER SURVEY

Is CCR diving right for me?

I think most rebreather divers and certainly all rebreather instructors have been asked that question at one time or another; and in many cases, more than just one time. Unfortunately, it is an impossible question to answer with anything approaching accuracy or truth, because the question is so ill-defined it is meaningless. One might just as easily ask: “How long is a piece of string?”

If there is a secret to getting a definitive answer, it lies in framing the question within a few well defined parameters.

Rebreather diving is dangerously close to taking on a sort of silver bullet status as the right solution for every type of diving. However, common sense, and a quick summary glance at accident statistics, tells us that it clearly is not.

Running a Closed-Circuit Rebreather is an order of magnitude more complex than throwing a regulator on a scuba cylinder and going for a dive. Dive for dive, operating a CCR safely requires divers to pay attention and develop a skillset way beyond anything required on all but the most complex open circuit dive.

For example, a sure sign that something is wrong with open-circuit life-support is that it stops delivering gas to the diver. This is a graphic indication that some immediate action is called for. A CCR system will continue to deliver gas to the diver but that gas may be totally unsuitable for his current situation and if he is not paying attention, he will continue to breathe until he passes out and dies.

Consequently, the risk-benefit analysis for CCR diving has a very different complexion to a similar analysis for open-circuit diving, tech or otherwise. Short version, there has to be a good reason to choose CCR over OC for any dive; better yet, there should be several good reasons to choose CCR over OC for every dive.

And with this, we arrive at an important waypoint on the way to answering the “is it right for me?” question.

Anyone asking this question needs first to define for themselves what they believe are the advantages of a CCR; what sort of conditions they expect to dive in; and how often they expect to dive. I think as well, they need to look seriously at their dive budget.

Operating cost is one so-called advantage of CCR that gets mentioned time and time again. Specifically that helium costs for deep excursions on CCR are insignificant compared to doing a similar dive on open circuit. For a new CCR diver, this cost benefit can be ignored.

If cost is a person’s main reason for switching from OC to CCR, they are in for a shock and cost should not be a final tipping point in the argument to go with a CCR. Consider first that there is a compelling body of evidence pointing out that for many tens of hours following certification on their unit, regardless of model or type, a diver should revert to tyro-level dives and forego “technical” profiles altogether.

For someone diving as a weekend warrior, this will probably translate into a year or two without seeing a hint of helium in their diluent bottle. (And anyone thinking of taking up CCR diving, especially experienced “technical” divers, should ask themselves if they are honestly willing to accept that “limitation” to their diving? If their answer is no, there is a statistically compelling reason for them to either adjust their thinking or drop CCR diving from their wish list.)

Without doubt, there are dives for which the best tool is a rebreather, but often the pros and cons sort of wash each other out and the final arbiter is personal or team comfort with regards to one or two ‘gray’ issues. I dive a rebreather as a default in but am far from committing 100 percent to it because there are occasions when CCR simply does not make sense.

I guess you could say that my answer to the ubiquitous “is CCR right for me?” question is that it depends.

Douglas Adams, the English writer responsible for The Hitchhiker’s Guide to the Galaxy, wrote: “There is an art to flying. The knack lies in learning how to throw yourself at the ground and miss.” I believe similar logic can be applied to rebreather diving. Sometimes flying is best but occasionally, the bus is a safer option.

Fitness and Flexibility for tech diving

This is an except from my newest book, The Six Skills and Other Discussions, due off-press in mid-February

The most sensible approach for someone considering a move into technical diving is to regard it as physically testing, and respect it as an activity that calls for above average fitness and flexibility. How much above average a technical diver has to be is a debatable point, and the rhetoric runs from the argument that technical divers should be capable of competing in triathlons to a completely hands-off approach that believes any diver is clear to go as long as he can stagger around the dive deck with sufficient control to stub out his cigarette and put down his beer before dropping into the water.

You may, like me, be looking for a set of fitness guidelines that fall somewhere in between those two extremes, and there are several suitable scales to measure personal fitness levels in a way that fits well with the general rigors of tech diving.

The first is the Cooper 12-minute run test. It is used to gauge aerobic endurance, and is perhaps the most straightforward to self-administer. I run a “diagnostic” on myself a couple of times a month and track the results on a spreadsheet. The test simply calls for the subject to warm up and then run as fast as possible for 12 minutes. Results are evaluated on distance covered within those 12 minutes.

A run of more than 2700 metres is excellent, 2300 – 2700 is good, 1900 – 2300 is average, 1500 – 1900 metres is below average and less than 1500 metres is poor. Over the years I have dropped a category but find it has been worth the effort to maintain a rating on the upper end of “good” for several reasons, including resting gas consumption rate.

(The approximate imperial conversions are respectively: more than 1.6 miles is excellent, 1.4 – 1.6 miles is good, 1.2 – 1.4 miles is average, 0.9 – 1.2 miles is below average, and less than 0.9 miles is poor.)

Running speed and endurance are good indicators for tech diving but so too is overall flexibility. There are two methods I use to test flexibility: modified sit and reach, and trunk rotation. Both are part of a whole raft of fitness tests published by the American College of Sports Medicine (ACSM), and I would recommend a visit to their website for additional ideas. Flexibility in the hamstrings and lower back have been an issue with me since childhood and I always find the first of these tests a challenge.

Modified Sit and Reach Test
This gauges the flexibility of the lower back and hamstrings and requires a box about 30cm (12 inches) high and a metre rule:
1. Sit on the floor with your back and head against a wall. Legs should be out straight ahead and knees flat against the floor.
2. Have someone place the box flat against your feet (no shoes). Keeping your back and head against the wall stretch your arms out towards the box.
3. Have someone place the ruler on the box and move the zero end towards your fingertips. When the ruler touches you fingertips you have the zero point and the test can begin.
4. Lean forward slowly as far as possible keeping the fingertips level with each other and the legs flat. Your head and shoulders can come away from the wall now. Do NOT jerk or bounce to reach further.
5. Slowly reach along the length of the ruler three times. On the third attempt reach as far as possible and hold for 2 seconds. Have your training partner read the score. Repeat twice and compare your best score with the table below. (All measurements in cm.)

Gender Excellent Above Average Average Below Average Poor
Male >40 cm 29 – 40 cm 23 – 28 cm 15 – 22 cm <15 cm
Female >43 cm 34 – 43 cm 23 – 33 cm 17 – 22 cm <17 cm

Trunk Rotation Test
This flexibility test measures trunk and shoulder flexibility. The only equipment required is a wall and a piece of chalk or pencil.

1. Mark a vertical line on the wall. Stand with your back to the wall directly in front of the line. You should be about arms length away from the wall with your feet shoulder width apart.

2. Extend your arms out directly in front of you so they are parallel to the floor. Twist your trunk to your right and the touch the wall behind you with your fingertips. Your arms should stay extended and parallel to the floor. You can turn your shoulders, hips and knees as long as your feet don’t move.

3. Mark the position where your fingertips touched the wall. Measure the distance from the line. A point before the line is a negative score and a point after the line is a positive score.

4. Repeat for the left side and take the average of the two scores.

Rating Positive Reach (cm) Positive Reach (inches)
Excellent 20 8
Very Good 15 6
Good 10 4
Fair 5 2
Poor 0 0

Because of the nature of water and the effects of buoyancy, above average strength does not seem to be as critically important for tech divers as it may be for other sportsmen and women. However, some strength building and testing is in order since divers with arms and legs like noodles will be at a distinct disadvantage moving gear from one side of a parking lot to the other, and may find it close to impossible to get themselves and their equipment back onto the boat in a big sea.

The US Marshal Service has a well-respected and openly published set of fitness and flexibility guidelines for the men and women on its staff. These guidelines have been used by some of the tech diving community for years. Some time ago while researching another book, I modified those tables and developed a set of values that seemed to work for most able-bodied course candidates. These values are based on the figures from the US Marshal tables for above average males in each age category.

My personal goal is to stay aged 30 – 39 for the next 15 years.  Some females find regular “military” push-ups difficult and I see no reason why the modified version cannot be used.

Age % body fat Sit and Reach Push-ups Sit-ups 2.4 km run
20-29 5.3 – 9.4 >50 cm >50 >45 < 10 mins
30-39 14 – 17.5 >45 cm >38 >40 <12 mins
40-49 16 – 20 >42 cm >35 >37 <14 mins
50-59 18 – 22 >40 cm >33 >35 <15 mins
60 plus 19 – 23 >38 cm >31 >33 <17 mins

Pre-Order your copy of my new book…

The Six Skills and Other Discussions is scheduled to start shipping February 16, and if you are interested in getting a copy as soon as it comes off press, now’s the time.

You can pre-order from the link below. You do not have to pay anything until your copy is ready to ship and then you will get an electronic invoice. I use paypal and have done for years. If that does not suit, we can work out something I’m sure.

Order Your Copy of Steve’s New Book NOW!

Pre-orders get free shipping in the US and Canada, and to make things fair, UK and European addresses will get a discount on postage. Will know more in a week or so but it looks like postage to the UK will be reduced to about 5 pounds per copy.

Many have asked what the book is about and I tell them it’s full of creative solutions for the puzzles that face tech divers on every dive. But I figured the table of contents would also help. So here it is:


Table of Contents

By Jill Hienerth……………

About this book ……………

Chapter One: Technical Diving and How to Get There From Here
Definition of technical diving and what to expect from a tech diving course……………

Chapter Two: Buoyancy, the force that opposes Gravity
The first of the Six Skills including a novel use for a digital fish scale……………

Chapter Three: Trim, the streamlined approach to diving
A prescription to swim like a fish and get rid of clutter……………

Chapter Four: The Skill of Movement and Position
The last of the physical skills and the guidebook for a four-dimensional game of follow the leader……………

Chapter Five: Breathing, beyond the standard advice not to hold your breath
The first mental skill and elements of gas planning……………

Chapter Six: Situational Awareness, the Chess Master’s skill
Focus, observation, understanding and a touch of clairvoyancy ……………

Chapter Seven: Emotional Control
The sixth and final skill, which is really about a developing a cool outlook and how to maintain it ……………

Chapter Eight: Dive Execution, Equipment Configuration, Doing What Works
Plan your dive, dive your plan and Hogarth ……………

Chapter Nine: The Deco Curve
Contingency decompression made easy. Well, easier ……………

Chapter Ten: Accident Analysis, and chalking the Foul Lines
What goes wrong when people get hurt and how we can learn from those incidents ……………

Chapter Eleven: Parting Shots
Suggested reading, diet, exercise and lateral thinking ……………

Imperial tables and examples for the metrically challenged ……………

Thanks for your attention, folks.

Why so many deaths? What’s the real story behind 18 deaths on rebreathers worldwide so far in 2010?

At the CCR Summit, part of the National Association of Cave Diver’s Conference in Florida early this month, during a presentation on rebreather safety, Jill Heinerth made the statement: “if you own a rebreather for five years, two percent of you are going to die on it.”

Part of the fallout from Jill’s presentation was disbelief and on the various dive and rebreather forums the debate continued for days, and continues as I write this. Hopefully, by poking this issue with a pointed stick, Jill will wake a few of us up to a real and present problem… and also perhaps help to fire-up the right people to work at making a difference.

First off, let’s see if things are as bad as Jill paints them to be.

I’ve worked with statistics and their analysis for a good part of my working career and have a healthy respect and suspicion of them. The stats Jill quoted in her presentation at the CCR Summit were drawn from a paper presented by Simon Mitchell during the Peter Bennett Symposium at Durham in 2005, and then updated and published by Duke University in 2007.

Mitchell, estimated the five year mortality rate for rebreather owners at 0.5 percent based on the number of rebreather fatalities recorded by Diver’s Alert Network (DAN) around the world that year, but warned his data was inconclusive and his estimate “statistically crude”. However, it is a good starting point and to clarify it somewhat, Mitchell confirmed recently that Jill’s figure would fit into the high-end of his paradigm if there were something like 4500 active rebreather divers during a year when 18 deaths were recorded.

One issue with any statistical analysis of CCR risk vs. risk on open circuit or diving generally, is that while we have a pretty good fix on the number of fatalities in a given year, we really have no clue how many rebreathers are out there. Nor do we know how many recreational divers are using them, and we certainly do not know how many rebreather dives are conducted each year (and that would perhaps be the most useful data).

The vast majority of CCR sales are associated with certifications sanctioned by and issued through one of the existing tech agencies. Getting reliable figures from them to cover CCR certs per annum is not easy and would be skewed in any case. For the record, one of the largest tech agencies states that CCR certifications at ALL levels make up less than 2.5 percent of their total numbers. But even interpolating from this figure is difficult because some divers own more than one unit, some certify and then become inactive, some take more than one certification in a given year, and some earn certification on the same unit at the same level with an instructor who issues multiple agency specific certs.

A useful number to work with would be what percentage of total diving related deaths occur on rebreathers in a given year. (The latest number I can lay my hands on is five percent, but with a whopping 18 CCR deaths so far this year, that figure probably will need updating by the end of December.)

What are we left with then? Not much frankly. We do not know how many people dive rebreathers. We do not know how many rebreather dives are made each year. But we do know how many scuba-related deaths there are in a given year, and we know how many occur on CCR.

So we come back to Simon Mitchell’s estimate. If we compare this to the deaths among DAN members over the past few years (1:6000 or 0.016 percent) CCR diving begins to look as though it is more risky than open circuit diving, but even that statement is difficult to corroborate without clearer and more complete data.

All we can really say is that too many people are dying on rebreathers and there must be something we can do about stopping it.

One of the questions Jill was asked at the end of her presentation had to do with the risk factors surrounding fully automatic CCRs and manually operated one. The question essentially asked if it was true that many more deaths occur on automatic machine compared to the manually operated ones.

Jill let me chime in because I dive and teach on a completely manual unit, and as much as I would like to say that manual CCRs are statistically safer, there are no data to prove it one way or the other! Manual, automatic, radial scrubbers, back-mounted lungs, scrubber cartridges or loose kitty-litter, multicolored lights, statistically they’re all the same, and more importantly I believe the problems behind diver accidents, injury and deaths have a common genesis that primarily is only indirectly related to technology.

I disagree with those insiders who suggest that the answer is third-party testing and CE or ISO certification for the machines. I do not buy that HUD (heads up displays), more oxygen sensors, carbon dioxide warning systems, or any other bells and whistles represent a silver bullet that will stop people dying on rebreathers. I think these are all fine concepts and are all worth consideration, but I don’t think they will really help or get to the fundamental problem.

At issue is poor initial instruction, diver complacency and a community ethos that sanctions, or at least ignores, bad habits and sloppy procedures.

I have no idea how much weighting or seriousness to give each of these issues because each is serious and each can lead some poor punter finding himself in a situation that has a better than average chance of a piss-poor outcome.

And sadly there seems to be no easy fix. Industry insiders like Jill Heinerth have been promoting change for years. Perhaps as a community, we can promote and campaign for the good and positive things too.

Here are a couple of pointers that may be of use to you.

If you want to dive a CCR, work with an instructor who understands the value of individual prescriptive training, and who pays particular attention to explaining failure scenarios; and how to work through them. Ask if there is a confined water component to your course. “Pool work” might not be exciting but it can help to build a strong foundation for you as a CCR diver. Find out how the inwater time during your course will be spent, especially the open water dives. The total number of hours is not really an indication of a good course if they are spent sitting in a lotus position looking at fish. Mastering CCR diving takes work and practice, and failure-driven improvements to your awareness and technique.

Ask your instructor for the checklist he uses before his personal dives. If he says he does not use a checklist, run away and find another instructor; seriously. I’ve taken courses with instructors who designed and engineered (and in one case built) the units they were instructing on, and ALL of them without exception, used a checklist before a dive. A checklist can save your life. Use one, always.

Most of all, do not put yourself above your training. All your experience as an open circuit diver is only relevant to diving a CCR after you have bailed out and even then, there are things unique to CCR that you will need to learn and practice if you want to get to the surface intact and whole.

When you first dive a CCR you are a beginner and no matter how good you are on open-circuit, resist the temptation to leapfrog over a training level or two because you believe know all about decompression or trimix or overhead environments.

Finally, take responsibility for your actions. One of my early mentors was W.R. Morgan and his advice was that before you take a shortcut related to any form of high-risk endeavor, from rock climbing to mountain biking, skiing or technical diving, take a piece of paper or index card and divide it into two columns. At the top of one, write “Normal Procedures” and at the top of the other “What I’m going to do instead.“ Now fill both columes in. Take a look at it, sign and date it, now give it to your boyfriend, girlfriend, wife, husband, best mate, favorite waitress, mom or dad, and let them know that if something happens to you, to give it to the folks who will be doing the investigation.

My final thought is this. I dive a CCR because sometimes it is the right tool to do what it is I have to do or what I want to do. All indications are that CCRs present a special level of risk. My training, common sense, and a bunch of procedures and protocols will help keep me safe, and I promise to practice them always.

Now, how about you?

Thanks for your attention.

A word about training: Price vs value (directed at those of you who want to teach for a living)

There is a great scene in the 1994 Quentin Tarantino movie, Pulp Fiction where Mia Wallace (Uma Thurman’s character) orders a $5 milkshake. Business consultant types use Mia’s expensive tastes to illustrate one of the Five Ps that constitute marketing’s basic tenets; in this case Price.

Any self-respecting MBA will tell you that Price is a function of Cost + Value. In other words, the cost of the milkshake’s ingredients has little to do with its price on the menu. The lion’s share of the five dollar price tag is to pay for the value added to the shake by it being served at Jack Rabbit Slim’s trendy themed restaurant. The Jack Rabbit brand is the added value making up the “Price equals Cost plus” equation.

The point is that Mia’s date, Vincent Vega, played by John Travolta, thinks five bucks was a lot to pay for some ice-cream and milk; but he is curious what makes it “worth” the money. When it arrives, he has to take a sip. In Marketing-speak, Vega has suspended his aversion to the sticker price for long enough to “give the brand a chance to hook him.” We might say that the display in the store window has stopped him in his tracks and he has walked into the shop. Vega has become a potential customer of the $5 shake, and is ready to be “sold” or more precisely, closed.

You may or you may not be a fan of Tarantino, milk shakes, and Uma Thurman, but the odds are that you “own” a brand. The smart bet is that you fit into the model that describes the majority of consumers, and there is something you buy regardless of its price because you value the brand – Lacoste polo shirts, Guicci fashion, Louis Vuitton luggage, Christian Louboutin shoes and bags, Roger & Gallet soap, Rolex watches, the list goes on, and it includes a whole raft of everyday products and services, not just the luxury brands.

In the business of marketing, which is business pure and simple, selling brand awareness and ownership to the target consumer is issue number one. Discovering what price the market will bear for that brand comes a close second; and is driven in part by a deep belief that quality has a bearing on price. High price equals real value; discount price equals low value. “Starbucks coffee really is worth the extra few dollars because it is so much better!” True or False?

Now let’s change gears entirely; let’s apply what we have learned from Tarantino’s milkshake, and a double, skinny latte to buying technical diver education. Specifically, let’s break down cost and value of a technical program to explain price.

Take my situation as an example. Let’s say that I need to build a new business plan and my financial “guy” – a true eccentric with credentials in law and forensic accounting – has asked to see a detailed breakdown of an “average” course. Because of his background, and because I have known him since the era of the “Blondie is a Group” button campaign, bullshit is totally not an option.

To work then.

The cost of materials and the cost of delivering a day of training per student can be worked out with the help of last year’s stats, some informed estimation, and careful scrutiny of all the things it takes to maintain active status as a technical instructor. This includes all the normal cost of business items needed to run a diver training facility from insurance and paperclips, to $2400 drysuits and vehicle maintenance.

I prefer to have this figure worked out to give a dollar figure per student per day. This means that if a program takes one day or ten, ballparking a cost is simple multiplication. Working this way does mean that my business plan projects similar per day costs for a simple intro to tech class conducted at a maximum depth of about 20 metres and a much more complex advanced trimix class held in 100 metres of water, which skews some of the fixed costs. But that’s OK. Accordingly, we will say this number is X dollars per student per day.

So that’s cost, now how about the added value; what do I add to a course that justifies me charging more than a straight $X a day, 4 x $X for a four-day program?

Because teaching is what I do, the value component is important to my survival and has to supply me a living wage; a profit. But is that an added value for my customers? I don’t think so. In fact it has nothing to do with it unless I market my classes as a sort of Support Steve Lewis’ Lifestyle Program. And I do not think that will work too well.

But if that is not the value, then what is? Perhaps this is where another P of marketing should be brought into play; what exactly is the product or service that I sell… that YOU will sell?

Well, we could itemize a whole list of things, time, security, adventure, empathy, a slightly off-kilter perspective, a scientific mindset, bad knees, green thumbs, etc. But it really boils down to experience. I have accumulated a lot of experience diving and teaching. By the time you start to teach technical programs, my hope is that you too will have a store of experience to dive into when faced with the eager faces of a class filled with students ready and willing to have you take them to some god-awful depth in the back of a decaying hunk of steel and wood surrounded by water moving at a couple of knots.

Perhaps also important on the Richter Scale of earth moving experiences is that you are still interested in building your personal experience. Simply put, this translates as: Dive for fun and occasionally, do something that shakes you out of complacency. A really well-known instructor I know says that part her value statement is that she is always scared.

So what’s all that worth I wonder? That stuff is the added value! All I have to do to satisfy the new business plan is to put a per-day cost on all that and fire it off to Mr. Bean Counter. So how much? Does $Y sound about right?

I like good pottery. In particular, I love simple pottery bowls.

Perhaps I like them because I have tried to make a pot and with authority can tell you that I am the second worst potter alive in the world today. In any event, I appreciate the space a good bowl takes up, and knowing this someone told me a story one time about a famous Japanese Zen potter who was being interviewed by a writer from a big circulation American magazine. As the journalist was asking questions, snapping photographs and taking notes, the potter continued to turn his treadle and throw pots. During the course of the interview, three or four dozen perfectly formed bowls took shape on the potter’s work bench.

With the interview drawing to a close, the writer asked how much one of the bowls would cost. “About four or five hundred dollars,” said the potter. “Holy shit,” the journalist said, rather undiplomatically. “Five hundred bucks and they take you about 30 seconds a piece? Wow!” The potter laughed and said, “well, that’s not exactly true.” He picked up another ball of clay and threw it exactly onto the center of the spinning wheel. “Today is my birthday and I am 77 years old. So this pot I am making now took me 77 years AND 30 seconds to make!” He looked at the journalist and smiled. “How long does it take you to make 500 dollars?”

No, thinking about it, perhaps $Y is not enough.