How do I get there from here… Step one on the road to Technical Diving


Here’s a very simple piece of advice if you’re being pressured — by your mates, your instructor, or a little voice inside your head — to sign up for a dive class. BEFORE wasting time and money on another course and its accompanying piece of plastic (or eCard): “GET A PLAN.”

Base that plan on what you want out of diving, and how much of your free time — and disposable income you want to dedicate to your plan.

Also, it will help motivate you if you work towards your goal with a buddy who has similar aspirations. Kinda like having a running mate who you can trust to ignore the rain and the wind, and to meet you at o-dark hundred on winter mornings to jog 10 k.

And finally, be realistic with your schedule. You will be doing yourself a disservice piling training sessions one on top of the other. PACE yourself. There’s no prize for the one who “finishes” first.

(Well, two things about that: there is no finish, at least none I can see. After more than 20 years teaching technical diving, I’m still learning; Secondly, you will grow more and become a better diver by punctuating your dive trips (read “experience gathering expeditions”) with targeted training sessions rather than the other way round. There is certainly no set ratio; everyone is different, but think about starting out by saying for every thousand dollars/pounds/Euros/shiny beads I spend on travel, I’ll put 200 in my training fund piggy bank.)

Okay, so here are ten tips to help you get your plan created:

  1. Have a long-term goal in mind. “I wanna dive the Empress of Ireland, the Bianca C, and the MS Mikhail Lermontov; I want to swim the Grand Traverse; I see my future-self on a rebreather at 100 metres taking samples for scientific research; My daughter and I have a trip to Truk Lagoon planned and I wanna be ready, etc.” All perfectly valid goals. Write yours down on a piece of paper and stick it on the fridge door.
  2. Create a budget for time and money. Quality training cost money. For many classes with a professional instructor, you should be planning to spend $250 – $350 per person, per day on average. Most classes, complex classes like cave or decompression or basic CCR, can last five or six days. By all means research your choices; get booked with someone you’re happy with, but don’t skimp on money or time.
  3. BEWARE of any operation/individual guaranteeing you’ll get certified. Technical certifications are earned not bought, who knows how you’ll do? There are no guarantees you’ll pass; but a good instructor will make sure your experience will be money well-spent.
  4. Create a timeline… with waypoint so your progress can be followed. You’ll need help with this. Ask advice. Then get a second or third opinion. The answers will tell you a lot about the instructors/operations/dive shops you ask!
  5. Think laterally when searching for help with training (your pathway might take you away from your local dive shop and towards an independent professional, it may take you to the next town or out of the country. So, THINK GLOBAL… it’s make you grow.
  6. Ask: Am I ready to have most of what I know about diving, challenged and modified?
  7. Am I willing to travel?
  8. Do I do well with constructive criticism? Technical instructors are trained and conditioned to pick bad habits apart. The process can be unsettling for a student with “issues.”
  9. Are you aware that going deeper, staying longer, breathing different gases, swimming in overhead environments all carry more personal risk of injury, death or worse?
  10. And finally, you need to understand and appreciate that some forms of diving are addictive. They will take over your life. Are you ready for that?


Good luck and “Dive Safe!”

Stage-bottle logic


There are different schools of thought about the “best” way to manage gas volume when cave diving with stage bottles.

The so-called traditional method is to treat the gas carried in stages, exactly as the primary gas supply: breathe one-third on the way in; one-third on the way out; and leave one-third for contingencies. If nothing hits the fan on a dive following this method, divers surface with stages, and primary cylinders each about one-third full.

Yet another option is “half + 15.” With this method, contingency gas for the stage is carried in the primary cylinders. This method requires a little more thought and arithmetic; but is considered by some to be the most conservative and best method when multi-staging. If everything goes smoothly when employing this method, divers surface with stages close to empty, but with all the contingency gas in their primary cylinders, which — with a single stage — translates into the primaries (twins or sidemount) being around half-full or more.

And finally there’s the seat-of-your-pants method which like half + 15, allows around half the volume of the stage bottle to be breathed, but critically, unlike half + 15, does NOT preserve any additional contingency gas in one’s primary cylinders. Provided nothing goes awry, divers using this “technique” surface with empty stages and primary cylinders with about one-third remaining. You don’t have to have a phD. in risk assessment to realize this is the most “liberal” way to dive stages; if anything dramatic happens, it can mean that divers do not surface at all.

But let’s leave discussion on the pros and cons of each method as the topic for a later blog post. Let’s focus instead on an error we should avoid when diving with stages in a cave regardless of which gas management rule we follow. That error is dropping a stage immediately its turn pressure has been reached.

It seems to be a more logical, more conservative, and therefore better practice to carry the stage and it’s extra gas a little further into the penetration.

Let’s look at a couple of disaster scenarios, and see why the habit of carry stage bottles a little deeper tends to be the better option.

Two divers (the ubiquitous Diver A and Diver B) have planned a stage cave dive. For the sake of simplicity, each is using the same size primary cylinders and each has the same sized aluminum stage bottle. Each has identical consumption, and fill pressures in all cylinders are identical. (An unlikely situation, but convenient for our purposes!)

Also, to forego any confusion over bar/litres or PSI/cubic feet, let’s consider the starting pressure in the primary bottles as 3P; and in the single stages as 3S. Our divers, A and B opt to dive following the Rule of Thirds in both primary and stage bottles.

OK, scenario one: Our divers begin their dive and, conventionally, breathe from their identical stages to start their dive. After a pressure drop of 1S, they drop their stages… each has 2S of gas remaining .

They swim on breathing primary gas. They each consume 1P of primary gas and signal “turn the dive.” At precisely this moment, Murphy joins their dive, and Diver A has a massive problem with his primary gas supply. He signals his buddy, and they share gas. Now Diver A and Diver B are breathing from Diver B’s 2P volume of gas.

If things go well — no entanglement, no slowing down because of restrictions, no elevated breathing rates, no taking a wrong turn in the confusion, and no arguments over navigation — they make it back to their stages with zero pressure in Diver B’s primary cylinders.

They grab their stages, and spend the rest of their exit thinking about how close a call they just had. They each surface with 1S pressure of gas in their stages, but zero in their primaries.

OK, scenario two is similar: But in this case Diver A and B when they have consumed 1S of the gas in their stages, switch to their primary gas, and opt to carry their stages a five or six minutes, or more, further into the cave before dropping them.

At the same point in the dive — just after the turn — Diver A suffers the same disaster, and has nothing to breathe. So, both exit breathing from Diver B’s 2P volume of gas; however, in this case, they reach their stages a few minutes earlier than in scenario one. There is gas in Diver B’s primary cylinders when they pick up their stages and continue their exit, during which they give thanks that they carried their stages further into the cave.

They surface with less than 1S of gas in each stage having perfectly justifiably used some of the reserve contingency gas in those stages to exit calmly. Diver B has some gas in her primaries; and, as in scenario one, Diver A’s cylinders are still empty.

Now we might argue the likelihood of the type of complete gas loss Diver A suffered in both scenarios one and two as remote… highly rare, probably impossible. But what cannot be disputed is that in scenario two, by carrying their stages for just a few extra minutes during their swim in, they had contingency gas placed in a better place than in scenario one.

We can debate how best to manage contingency gas volumes in stages (there may be benefits to each method), but in most cases it seems a better, more logical option to think before you drop; and wait.

Dive Safe!

Double Arrows… what do they mean exactly?


Cave divers have a secret code… well, according to a non-cave-diving buddy we do. And perhaps she’s right; we do have a few odd hand-signals that are specific to cave diving.

What I did not mention to her when explaining the peculiarities of “ I’m Stuck,” “Changing Second Stages,” “Tangled in Line,” and “Okay buddy, I’ll help yer, but you’re gonna owe me…” was that some of the basic signs we take for granted in North America, are not universal in every cave-diving community.

Double arrows indicating proximity to a jump / side passage is a good example. (See the photo below.) Outside of North Florida, this may or may not signal what it does here: time to tie in a jump spool, fix attendance cookies to the gold line, and “Let’s go roaming!”


What’s perhaps more baffling is that even in the North American cave diving community, there’s a general misunderstanding about what exactly is meant by another set of double arrows.

The picture below shows two directional arrows pointing in opposite directions. Similar but with a very significant difference… well different certainly… but how!?


Until recently, I thought it generally accepted that this particular configuration indicated the mid-point between two “Ends of Line.” But during the past month, diving various caves but none separated from another by more than a two-hour drive, I heard it referred several times as indicating a “Safe exit in either direction” or “The halfway point between two exits.”

While it’s a fact that an end of line — a break in the main line — is usually where the overhead has a hole in it and daylight streams into the blackness of the cave proper, that is absolutely NOT the same thing as a safe exit; and the difference is more than a question of semantics, with the potential for a bad day ahead for assuming it is.

So, lets think about why this is.

A cave diving team, unless one of them’s clairvoyant, can only be sure of one safe exit: the one they came in by. Everything else is a mystery, and in truth, in a few cases there’s no absolute guarantee that when they get back to the hole they came in by, it’ll still be passable. Perhaps the only sure bet is large, open caverns like the entrance to Jackson Blue Springs in Jackson County, on Florida’s panhandle.

Caves, and especially sinkholes, have a dynamic nature. A sinkhole that a diver could climb in and out of yesterday, may have suffered a mini-landslide overnight making it impassible today. A tree providing shade last week, may have had its root system undercut by yesterday morning’s downpour, and is now sitting in the sinkhole like Aunt Zenia’s potted aspidistra: short of digging out, there is simply no exit now. A rock may have fallen from the ceiling a few feet from the sinkhole blocking access with an immovable chunk of limestone and 40-million-year-old fossils.

So, that’s why it’s a little risky to assume the mid-point arrows indicate anything other than equal distance between two ends of the main line, and nothing more… at least that’s the case in North Florida.

“Teaching” yourself Situational Awareness (SA)


SA is not easy for an instructor to teach. Since some level of SA is innate for most of us, many instructors opt therefore not to include an SA module in their technical diving programs, preferring to simply “mark” a student’s SA as there or not there. Of the instructors who DO include SA in their classes, most do so with an understand that their role is to create a non-threatening, learning environment… she/he facilitates rather than teaches, because, with a little guidance, most students — with direction — do fine once they’ve been show the value of SA. It’s more efficient that way, but hereare some “techniques” I believe may help you (or your students if you teach) become more aware: more clairvoyant. 

Awareness — both in water and out of it — is a choice. We have to choose to build awareness of what’s happening around us: and how what’s happening now can influence what is going to happen next either positively, or what’s more important, negatively. So, when we dive — and especially when we dive deep or in tough conditions, or in an overhead — rather than being pushed from moment-to-moment with the flow as it were, and with no idea of what comes next, we can project “current events” into the immediate future. This  helps to protect us. With this skill, we can focus on things that matter — threats — and ignore the superficial and unimportant things that have no real importance — things that are simple distractions. Developing this skill takes time, but — with very few exceptions — we are all capable of its mastery. And without exception, developing and refining this skill will make every diver a better diver.

First we have to understand what a baseline is. A baseline is normal activity: noise; motion; actions; a series of things unfolding as they should in an anticipated order; everyday things that signal things are just fine and will stay that way — at least until something changes… and it’s that change we need to notice, understand, and be mindful of its implications.

Here’s a suggestion: begin in a quiet space… like a park or backyard. Be still and silent. Listen to what’s going on around you. If this were the 1970s and we were sitting around burning incense, and a block of Hash, I’d say: “Still your mind.” Since it’s not; and we’re not, let’s simply say, Focus on this baseline; it is the norm for that environment AT THAT TIME. Consider anything a threat that is not part of it; any odd noise, movement, circumstance… a dog suddenly barking, for example. Consider anything out of the norm, a potential threat… develop a healthy paranoia!

If possible, have someone introduce non-baseline “threats” — a footfall, a mobile phone alarm, a ball being kicked, a door opening, closing, being locked. Learn the appropriate reaction to each. Practice, practice, practice…

Try the same exercise in a shopping mall… more noise and a different baseline, but a baseline nevertheless.

Building awareness of the environmental baseline will help you to switch focus onto things that carry the potential to derail plans or possibly harm.

Now move your baseline awareness exercises to confined water

The secret of making any progress at all is to be relaxed and to be able to maintain your position in water column with quiet hands and feet. Your “consciousness” has to be directed away from yourself, so if you’re constantly fighting for buoyancy and trim, you will not have enough awareness left over to gauge and monitor the baseline!

Once you can focus on the baseline, have a buddy introduce “distractions” (displaying minor simulated problems with gear… letting an unclipped backup regulator hang loose, a fin strap not in position, a mask fogging up, rapid breathing, etc.) Practice these simulated “threats” during skills development dives. Document what is noticed and what is not. Simulate multiple oversights in gear and technique between you and your buddies… errant fin strokes, loss of buoyancy control, failure to respond to hand-signals. Make your debriefs learning exercises.

Enlightened self-interest tells us that a problem with our buddy’s gear, his or her piece of mind, lack of skill, is a potential  problem for us. That’s one of the most important values of good SA!

Most of all, apply what you learn on every “real” dive not just “practice” dives. Try to expand your SA every time you get into the water. I guarantee you’ll get more enjoyment — and less threat — out of your diving.


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


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

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

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

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

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

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


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

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

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

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

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

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





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


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

Hang on… that needs to be rephrased.

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

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

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

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

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

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

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

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

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

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

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


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


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

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

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

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

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

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

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

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

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

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

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

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

“Unusual treatment or condition” means if the cylinder:

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


Dive Safe… be careful out there.