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The Five Rules for Safe Cave Diving

Cave diving has been taking place since the 1960s, and unfortunately, there were some accidents. But, after reviewing many of the accidents, cave diving instructors and explorers, like Sheck Exley, determined that many of the accidents had resulted from the same mistakes. As a result, the following five rules for safe cave diving were developed.

Proper training and not exceeding your skill level and limits is the primary reason for cave diving accidents. Many of the cave diving fatalities over the years have been because the diver wasn’t cave certified or was trying to do a dive that was well beyond his/her abilities. Without the proper training, cave diving can be an extremely dangerous sport. Cave diving requires a special mindset, special techniques and equipment, and procedures that you can only get in specialized cave and cavern diving courses. No amount of experience, number of dives, or open water certification level is enough to safely cave dive; you must participate in cavern and cave diving courses to conduct safe cave dives.

Use a continuous guideline from the entrance of the cave and throughout the dive. Without a continuous line, you’re relying on memory to find your way out of a cave. Caves do not look the same on the way out as they did on the way in. Visibility can change, silt outs can occur, lights can fail, which all can contribute to getting hopelessly lost. A guideline to the cave’s exit is basically a lifeline; it’s the route out. Always run a continuous line from the entrance of the cave and throughout your dive. Don’t make jumps without running a gap line. Don’t assume that since you’ve dove the cave before that you don’t need to run a line from the entrance, things can change from dive to dive.

Always reserve at least two-thirds of your beginning gas supply for exiting the cave. This is also known as the Thirds Rule. Exhausting more than one-third of your gas supply for the swim into a cave does not allow for adequate reserve amounts. If you use one-third to go in, you’ll need one-third to exit and will have one-third for emergencies. The thirds rule is also extremely important in buddy teams. If a team member had a catastrophic gas loss at maximum penetration and had to rely on their buddy’s gas supply to exit the cave, the two-thirds of remaining gas would be required to get both divers out of the cave safely. Cave environments are not all the same, meaning that the thirds rule may have to be altered. If you’re diving in a siphon system, swimming out of the cave against the flow may require more than one-third of your gas supply, meaning that you may not want to go until you’ve used up one-third of your gas. Other adverse conditions may require a more conservative gas planning strategy as well. Each cave dive requires specific gas planning. Don’t just assume that the Thirds Rule applies everywhere.

Limit your dives to the operational limits of compressed air (130 fsw). Diving below 130 fsw on standard air increases the risks of nitrogen narcosis and the deeper you go increases your chances of getting oxygen toxicity. With the modern day advances and applications of mixed gas diving, there is no reason to dive deep on air. Trimix training is available through many of the training agencies. Mixed gas diving reduces nitrogen narcosis and oxygen toxicity, which in turns drastically increases the safety of a dive. If you can’t afford to get trimix certified or purchase the helium needed to conduct a dive, then limit your dives to recreational limitations of 130 fsw.

Always carry at least three battery powered lights on every cave dive. On a cavern dive, where the natural light acts as a third light, you only need to carry two battery powered lights. Lights are sometimes the most vulnerable pieces of dive equipment, meaning that they can fail easily. Bulbs can blow, wiring can fail, and batteries can fail. By carrying at least three backup lights, the likely hood of all three lights failing on the same dive are slim. In addition to just carrying the lights, you need to make sure you take care of your lights. Change your batteries frequently and make sure rechargeable lights are charged prior to the dive. If you have a lot of hours on a bulb, you may want to replace it before it fails. Without proper and reliable lighting, cave diving can be a very dark sport.

Setting up and attaching side mount cylinders

Diagrams below by Curt Bowen

Proper set-up of your side mount cylinders is essential to maintain proper buoyancy and streamlining. Cylinders mounted on your side must be positioned correctly for ease of use, safety, comfort, and proper swimming techniques. If your cylinders are hanging low and riding on your torso, the ability to navigate tight restrictions is lost and your streamlining is gone. Knowing how to rig your cylinders is essential for keeping them stationary in their correct position on your sides.

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Cave Diving for the Silver Screen

by Andreas W. Matthes

Cave diving in Romania is something not offered all the time and when friend, Underwater cave cinematographer and photographer Wes Skiles of Karst Production was asking me some years back during a NSS-CDS cave diving convention in Lake City, Florida if I like to go cave diving in Romania naturally I was curious and it turned out to be quite a cave diving experience indeed.
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Hogarthian Gear Configuration

The Diver vs. Murphy’s Law

by Jeff Petersen


Hogarthian diving is generally considered a specific “configuration style ” of back mount cave diving and there are numerous articles out there on the specifics of the Hogarthian configuration. Instead, this article is more about the psychological underpinnings and guiding principals of Hogarthian diving. The Hogarthian mindset and its concepts can be applied to the various forms of cave diving (and other types of diving).

With the plethora of articles expounding on proper hose lengths, regulator locations, and fittings, such a focus on the gear configurations isn’t necessarily a bad thing. Instruction on the specifics of gear configuration does allow the adopter to immediately leverage the “lessons learned” by so many others in the past. However, this focus on the mechanics of gear set-up can often be at the expense of not giving students a sense of the underlying motivation behind the configuration. A little appreciation of the Hogarthian psyche allows students to tailor their configuration according to their specific diving needs.

In a subsequent posting, I’ll put together a primer on the specifics of the back mount configuration for those unfamiliar to Hogarthian Style.

The Hogarthian emphasis on both safety and efficiency – with near equal importance – is why this method of gear placement does more than any other configuration “style” to generate synergies that minimize risk and maximize efficiency simultaneously.

The Hogarthian mindset is fundamentally about risk management. This mindset was borne from an exploration-intensive environment. And since exploration dives are intrinsically more risky, all other elements of the dive needed to be managed appropriately to minimize the risk.

The following summarizes the Hogarthian goals and strategies (rather than the specific gear configuration that results from the concepts). From the goal statements, the mindset evolves and then, in turn, this leads to the conceptual tools that the Hogarthian mind utilizes to realize the goals.


* Maximize your safety – For those without chemical imbalances, this is the number one goal – for the obvious reasons.
* Maximize your efficiency – While technically a secondary goal, this is a very close second. Since cave dives tend to be very goal-oriented (e.g. “we need to make it 3,000 feet into the tunnel to look for a side tunnel”), the ability to make it with the least risk and effort allows greater success and safety. More diver efficiency makes a dive safer; all things equal, the more efficient you can be, the less likely you are to create riskier situations. And if you do, the efficiency gives you more resources (e.g. lower air consumption) to manage a problem in the most expedient manner.

Mindset of a Hogarthian diver

* Treat all dives seriously – whether large or small, familiar or new cave, complacency can be a killer
* Constantly seek to refine – not re-invent – your gear
* Dive Team/buddy mental synchronicity – dive with like-minded divers

Guiding tool/principles

* Minimalism – less is better (up to a point)
* Simplicity

– Idiot-proofing – making sure you can use the equipment as easily as possible under any conditions

– Bullet-proofing – elimination of unnecessary failure points

* Consistency of gear set-up (with a critical eye for constant re-assessment for improvement)
* Self-sufficiency – don’t be dependent on your dive team to save you; they should be an additional asset, not a crutch

The number one goal is safety, but we all know that we can’t engage in underwater activities with absolute safety. Since there will always be some degree of risk, the name of the game is risk management. In other words, what is (or what should be) your level of acceptable risk? Based on personal observations of divers, there is clearly a wide range of individual thresholds for acceptable risk. Unfortunately, many display an objectively high level of acceptable risk (based on their behavior), while their perception is quite to the contrary; they think they have a very low level of risk.

Dissecting risk… and your gear

Let’s break down the idea of risk into some manageable and more concrete categories to help illustrate how these concepts have to be addressed. Generally, risk increases with increased complexity. More gear equals more risks/failure points. Also a more complex item will invariably be harder to use properly in a stressful situation, thus increasing risk. These rules are bounded by the practical consideration that some increases to complexity introduces far more safety than the incremental risk introduced, such as adding an octopus (the back-up second stage) to your configuration. Generally, the increased safety it affords far out weighs the incremental risk of hazards such as free-flows and entanglement hazards. Of course these risks, in turn, need to be managed.

For the purposes of this discussion, I’m going to break gear risk down into three components: 1) Internal risk, 2) Accessibility risk, and 3) Environmental risk. Acknowledging that these components do, of course, have some interdependencies, let’s look at these forms of risk in greater detail. To help ground these seemingly academic distinctions, I will carry the analysis of our aforementioned second stage throughout the discussion.

Internal Risk

This asks the question, “What is the probability the gear will work as it’s supposed to when it is needed.” How complex is the gear? How many internal components (i.e. how many possible failure points are there in the item)? Are the components electronics, mechanical, or some of both? The more internal components that are crucial to the function, the greater the risk of failure (i.e. more failure points). While risk describes a level of danger, a failure point represents a component whose individual failure renders the equipment inoperable.

Taking our octopus example, the selection of what secondary to put on the end of the hose is crucial. While most of your gear is quite literally your life support system, many people place an inordinate focus on the cost of the gear. This concern over cost must be weighed carefully against what risk are being managed (or exacerbated). Why would you want your secondary regulator to be of a lower quality than your primary? If you have to resort to it, you should expect the same level of performance that your primary affords you. This helps reduce physical and psychological stress and in turn, reduces the likelihood of greater gas consumption during its use. To draw conveniently from a couple handy clichés to make the point: Do you want to place your life in the hands of “the lowest bidder?” And: “How much is your life worth?”

A secondary risk is, given a functional failure, what is the reparability of the item. Can the gear be readily repaired underwater (i.e. immediately repaired)? For example, second stages with screw off covers are preferred over models where the diaphragm cannot be accessed without tools. This allows for re-setting the pop-it and flushing out foreign objects that may be causing a free-flow or other undesirable events.

Accessibility Risk

This one is a little more obvious. Now that we have an octopus that should work as expected and, in the event of probable failures, can be fixed, we next ask: “Can the gear be deployed so that it can be used as intended?” In other words, can it be reached and deployed – regardless of the circumstances? With our new high performance and functioning octopus, we need to figure out the optimal location to store it. Since this is a back-up device, it has to be “stowed away” and may not be needed at all, but it must
always be readily available. One of the signature characteristics of Hogarthian configuration is the location of the octopus. It is worn like a necklace, resting just below the chin, held in place by a thin bungee tied around the mouthpiece. Ease of deployment is crucial. Given its location, some divers can retrieve it without using their hands by tilting their head down. For the less adept, it still takes only one free hand and a split second – even is zero visibility – to move the regulator into the mouth. If the necklace is too long the octopus will flop around and potentially get entangled with other equipment; it could also be more difficult to grasp in an emergency. If the necklace is to short, you can’t raise it to your mouth and keep it comfortable seated in your mouth for use. In the Hogarthian configuration, the octopus hose comes off of the regulator mounted over the left shoulder, laying behind the BC, and draped over the right shoulder. Hose length is selected to ensure that the second stage rests just below the chin and the hose doesn’t “hang” off the shoulder – another entanglement hazard.

Environmental Risk

Our last gear related risk asks the question, “What risk does the gear introduce that is unrelated to its function.” How will its presence – whether during use or “idle” – impact or be impacted by the environment? Is it an entanglement hazard with other gear? Does it hamper access to other gear or mobility? For example, will it impair the ability to use the power inflator or attach/deploy stage bottles? For our octopus example, one consideration is the overall size of the second stage. Larger stages create a larger profile extending off your chest. This can create a greater entanglement hazard in a very tight squeeze or even produce free-flows in tight all-rock restrictions. Are the exhaust vents and mouthpiece going to allow easy intrusion of sands, shells, etc? One solution to this is to place a section of window screen across the mouth so that when the rubber mouthpiece is attached, it holds the screen in place, taut across the opening.

While all of this may seem excessively academic and analytical, no one questions the value of having a back up second stage, but this illustrates just how focused the mindset of the true Hogarthian diver is on all the “little things” that could turn into big problems.

These attitudes can manifest themselves quite poignantly in dive site chatter. I have overheard countless divers describing their planned dive with boastful tones on how they were going to use multiple stage bottles and a scooter to reach the target penetration. To hear them talk, one would think they were getting points for each additional piece of equipment they could get into the cave with them. Conversely, a Hogarthian diver will pride himself on achieving the dive goal with as little additional gear as possible – while still remaining safe.

In the Hogarthian world, you don’t bring something unless you truly need it. True need here is the operative phrase and the more contentious consideration. We all realize that if a specific set of events occurs, our hypothetical item will be needed. In the end, these “what if” exercises boil down to gut-level probability analysis of the genuine likelihood of need, the items true value, and the risks it introduces during all of its “downtime.” Then – after all of that mental math – if you decide to bring it, make sure it works.

We discussed how the first macro risk is gear and that all of it will fail – eventually. The next macro failure point is you – your brain and your body movements. To minimize your risk of failure, you need to practice and configure yourself so that everything can become second nature, like learned instincts. Then, under stress, you don’t have to consciously manage your actions; instead, unconscious reactions suffice. One of the keys to the success of this concept is to always configure your gear the same way. Whether you are in a large or small cave, deep or shallow, everything needs to be in the same place. That way, your body and mind get trained where to reach for the octopus, the pressure gauge, the power inflator, without fumbling around or requiring thought.

On the brain side, stress itself is a huge risk factor. Since stress can lead to bad decisions and ultimately panic, the near elimination of stress is crucial for safety. Managing your gear – knowing where it is instinctively and using it with ease – will avoid additional stress.

A term that has gained significant popularity as a community and market segment is “Tech Diving.” Unfortunately, the “tech” in Tech Diving means technical and technical translates into gear – more and more gear. For the Hogarthian diver, “tech” is about technique. Technique can always be counted on – you always have it with you.

Another consideration as a failure point is the rest of the divers in your dive team or other divers diving in the system during your dive – or even previous to your dive. Can you trust your life on a stranger’s placement of a line arrow pointing the way out?

While this topic warrants a separate posting to do it justice, for now, the key take away is that your dive buddies should have the same mentality and gear configuration. With the same configuration, each diver is better poised to help each other out. This can be crucial in low visibility and stressful situations where your next action may make the situation safer or much more deadly. You know where everything is on your buddy when he’s having a problem, because it’s in the same place on you – the gear placement that has become second nature for you from consistent placement and practice.

Some people think of the Hogarthian style as rigid and stagnant. The Hogarthian configuration does continue to evolve, although its evolution now is in incremental refinements rather than massive redesigns. Changes to the configuration are based on more of a “scientific method.” A change is proposed, analyzed and evaluated by peers, tested, and then if the test results bear out, adopted. Of course, there is no “Hogarthian Institute” that reviews and ratifies revisions to the doctrine, but there is a strong word-of-mouth-community where new refinements are vetted and either adopted or abandoned based on experience.

Ultimately, understanding and embracing the Hogarthian mindset ensures that when you tailor your configuration, it is a genuine enhancement appropriate to the specific peculiarities of your diving needs. While the Hogarthian goals of safety (risk reduction) and efficiency (getting the most out of your dive) are grounded in cave exploration, the Hogarthian mentality can serve any diver well – be it 30 foot reef divers, nitrox or mixed gas divers, deep wreck divers, or spearfishermen. No matter what kind of dive you’re doing, there’s always a fair amount of effort that goes into making it happen, so you want to get the most for your effort and money. And regarding safety, we’ve all heard the admonition “it only takes a few inches of water to drown.”


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Uchben Bel Ha – Mexico

by Sergio Granucci

A new cave to explore just 5 minutes from my house…

Over the past years, the Labnaha exploration team has explored more than 80 cenotes north of Playa del Carmen in the state of Quintana Roo, Mexico.   In this area, a great number of cenotes are still waiting to be discovered and explored.

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