Skills Necessary to Conduct CCR Dives Utilizing Helium

There is no fluff when it comes to CCR diving. Each step has value and should be followed as prescribed. And that’s not just my opinion, it’s the best, safest and most secure way.

Cave diving 101: Avoiding Entanglement

by Steve Lewis:
cave diving 101
Scuba diving seems to make an appearance on just about every sports writer’s list of the most dangerous recreational activities; and my guess is that when asked, every single one of the men and women compiling those lists would rank cave diving the most dangerous form of scuba diving. For example, Forbes, the venerable business magazine famous for listing things like the world’s richest person, most expensive car, or blingiest wristwatch, puts cave diving right up there with bull riding, base-jumping and surfing monster waves. With respect – and with a nod of the head to the personal bias resulting from being an avid cave diver – I feel we should temper any belief in the accuracy and relevance of these lists with the knowledge that they are put together by writers happier conforming to uninformed generalizations, than researching primary data and supportable statistical evidence… but let’s not go there right now.

Let’s say instead that although cave diving presents divers with an alarmingly long list of potential risks, those risks are well-managed and suppressed to a perfectly acceptable level by following a few quite simple rules. Sure, cave diving has the potential to be dangerous, but when we follow best-practice guidelines, the stats reflect a totally different perspective: in short, the level of danger is inversely proportional to how closely we stick to well-established guiding principles!

Paramount among these principles is having the relevant instruction, up-to-date experience and practice with the appropriate kit and skill set, and staying within personal limits.

For example, let’s consider entanglement… and the steps cave divers learn to reduce the dangers entanglement present.

Even if you have never been inside a cave, you may already know, those dived on a regular basis have a network of permanent lines and navigational markers in them. These lines (usually color-coded kernmantle), are fixed in positions that make them easily seen, and not easily tangled in fins or other gear. This helps to make getting snarled up in them unlikely: especially compared to divers who penetrate wrecks, which often have a horde of cables, nets, wires, and ropes ready to reach out and grab at passing dive gear. But cave divers are also taught a few skills to further ensure any interaction with lines is visual only.

The first step in the process of managing entanglement risk is to streamline one’s personal dive gear. This is part of the process that every Cavern/Intro Cave/Full Cave student is walked through with his or her instructor usually well BEFORE diving in an overhead environment.

Chief culprits are the “danglies”: any accessory, any piece of harness, any clip, reel, spool, light, or regulator second stage not tucked away either out of sight in a pocket or pouch or “hidden” making contact with permanent lines improbable.

Another step in the streamlining process is to “trim the fat” from one’s dive gear. This means to take only what’s needed, and to leave behind what’s not. For example, some divers like to adorn themselves with every piece of kit they can pick up and carry to the water. It’s not unusual to see divers (even cave divers) with five or six additional reels and assorted spools attached to their harnesses. Make no mistake, every member of a cave-diving team MUST at all times carry a safety reel or spool, but taking “three or four or five extras just in case” is overkill. Especially when the dive plan calls for no deviations from the main line or gold line. OTT (Over-The-Top) accessorizing is unnecessary and encourages the Christmas Tree approach to kit configuration!

With this in mind, we can segue to the topic of “line traps”, places on a diver’s kit or person that a line might get pushed into, making removal difficult, time-consuming, or darn right dangerous. Classic line traps include manufacturer’s standard fin and mask straps (which are either taped or replaced with better options); swing-gate boat clips (which are sometimes called suicide clips and typically replaced with bolt snaps); anything behind the diver’s back such as a doubles manifold or a tangle of reels and spools clipped to the diver’s butt; or a side-slung stage, bailout or decompression bottles (which should be pulled in tight to the body’s lateral line a la sidemount configured tanks). Most of these can be managed or eradicated completely using a little creativity, judicious gear selection and editing, and common sense, but some simply have to be accepted as inevitable (the behind the head paraphernalia for anyone diving backmounted doubles or a rebreather for example), and dealt with accordingly.

And this brings us to what is perhaps the most important skill, and certainly the one most difficult to acquire: positional and situational awareness.

Cavern and cave diving students learn that they should strive to develop complete control of their buoyancy and the ability to maintain their body in an attitude best suited to the conditions: often, but not always, horizontal trim. As these skills begin to develop and become finely tuned, a diver’s awareness expands to provide them uncanny feedback regarding the exact position of their hands, feet, fins, body, equipment, accessories, etc. relative to their environment. This makes it possible for them to maneuver through restrictions, glide past snags, over, around and under lines without coming into contact with anything.

Most of all perhaps, the seasoned cave diver understands the Zen-like concept of being in the moment… and being in no rush to get anywhere. Yes, the most common mistake made by new cavern and cave divers is to behave like a puppy at the beach… or perhaps more like a bull in a china shop. Slowing down, taking one’s time will certainly be helpful, and will help avoid entanglement. And in the cases where something does become snagged, the Stop, Think, Act response taught in basic SDI open water classes, remains the best advice.

So, go out there and have fun, and if you should bump into that writer from Forbes, take the time to explain that cave divers are not nutcases with a death wish!

Can You Imagine Diving NYC? #risingsealevels

by Steve Lewis:

Diving NYC… Signed up for the dive trip of a lifetime #innundatedNYCTour. Really, really pumped!

Wow, #divetimessquare was a blast. Swum along Broadway. Not certified to enter theatres or subway but still fun!

How do they get the lights to work underwater? Fascinating to see all those neon lights shining through the kelp! #confusedbytechnology.

7th Avenue… Many gaudy fish species to be seen. Took lots of photos. Some swum very close to us. Not too sure what they were looking for from us. Very difficult to tell the males from the females! #whichiswhichgender?

Signed up for the DPV ride past the Rockefeller Center and on to Radio City Music Hall. Only the first handful of floors are underwater. Our boat tied up to one of the smaller buildings. Marine life was incredible. Lots of sharks though. Guide explained that there is a huge shark community around the old Wall Street. #skyscapersarefun

Dived Brooklyn Bridge today. Not a very pleasant experience really. So many dive boats trying to tie-up at same time. We waited 20 minutes to get into the water. #trafficjambrooklyn

The best part of the day was the surface interval. Vendors in small boats floated by selling every conceivable type of food from Dim Sum to Jewish Deli. #eatingrightinbrooklyn

MOMA and a swim around the sculpture garden. Not sure if the seawater has caused some of the weird corrosion or if that look was the intention of the original artist. #whounderstandsmodernart

Afternoon at Central Park Zoo. What a gas! Animals in air-quariums. Swam past some very confused looking apes, and almost brained myself when I bumped into a glass wall separating us from the polar bear enclosure. One thing I noticed, no need for “Do Not Feed the Animals” or “Keep Your Hands Away From Cage” signs. #differentperspectiveonsubmergedwildlife

Certainly getting the hang of touring a submerged city now. Understanding what to look for and what to avoid. We have a guided tour of a subway station tomorrow. A little worried about the overhead environment.

Subway station was cool and not underground at all but one of many stations on the High Line. Did a tour of the platforms, swum under the line itself with the street below us, and a did a guided swim-through of a parked subway train. Highlight was using the special cans of underwater spray paint to add to the graffiti already on the walls and carriages. Not much space left but managed to write: #ilovenyc and left it at that.

Highlight of the trip: diving the new Yankee’s Stadium! Truly great experience to swim around the outfield and up over the outfield bleachers. Not crowded at all. We were the only dive boat on site and we had the whole place to ourselves. Awesome to think that NY once had a baseball team! #redsoxrule!

Last day and a trip to New York Botanical Gardens. Have never seen so many corals and invertebrates. Filled one and a half SD Cards with photos. Tied up to the trunk of a huge old tree with thousands of birds perched in its canopy, and did our first dive around its roots and through a forest of water lilies. Tons of small fish, and many exotic species of aquatic plant. Swum around the huge dome of the biggest greenhouse I have ever seen. Probably my favorite dive of the whole trip. #flowersinthebronx

Diving Casualties of War

by Steve Lewis:
TDI war tank wreck on ocean floor

It was veteran journalist and author Tom Brokaw who first coined the term “The Greatest Generation” to describe those Americans who had lived through the Great Depression and who had fought in World War II. In his 1998 book of the same name, Brokaw wrote, “it is, I believe, the greatest generation any society has ever produced.” They fought, he wrote, not for fame and recognition, but because it was the “right thing to do.”

I am old enough to have a very direct connection to that generation… in its English variant at least. As a kid, WWII and the challenges that generation overcame, were as real and as much a part of my everyday life as Ilderton Road Primary School, New Cross Speedway and Millwall FC.

My mother, aunts and grandparents survived the Blitz on London, and walking to school, my mates and I passed by the ruins of a several houses destroyed during one of the hundreds of air-raids that city endured. Nobody seemed to think it odd or particularly remarkable that more than a decade later, the blasted and burned shells of family homes were left like decayed teeth among rows of otherwise normal looking, if modest, terraced houses in the street next to ours. For my friends and me, it was just a cool place to explore and play in, a situation that would send Health and Safety inspectors into a coma today.

During WWII, my father spent six years in uniform — much of that time in North Africa fighting the Afrikakorps — but he rarely shared stories. Most of any insight I gained about being “at war” came from an uncle who served on a Flower-class corvette assigned to convoy escort duty in the North Atlantic and Mediterranean.

“Uncle Dave” told me about the way his ship rolled around even in moderate seas, dipping her head with every wave and throwing salt water over everything and anyone on deck. He explained how crowded it was, with every inch of space below deck occupied with men or supplies… or both. He spoke about the constant and unappetizing diet of canned and powdered food, and the antics to find anything resembling real food whenever the ship reached harbor. He told me about standing watch on Arctic convoys dressed in every scrap of available clothing, but still feeling the bite of freezing temperatures. The day-to-day routine sounded relentlessly boring, and only occasionally punctuated by any action approaching the classic fight between the Royal Navy and the Kriegsmarine that we see in war movies.

There was no drama about these very occasional “adventures.” He had no flamboyant tales of dashing into action against U-boat wolf packs, and sinking them all. Perhaps this is hardly surprising since the approximately 200 “Flowers” that saw action in the British and Allied navies from 1939 to 1945, are credited with sinking only 47 German and four Italian submarines. His take on the Battle of the North Atlantic was far from romantic. “We lobbed depth charges into the sea that’s about the truth of it,” he said. His take on battle tactics was very simple. “The Old Man [the captain] would steam around hoping to keep the U-boats busy while the convoy disappeared over the horizon. No fuss, just like a drill.”

He spoke about no surface battles with marauding waves of planes trying to bomb the merchant vessels his ship was charged with protecting. No hand-to-hand fighting with crack troops from the Waffen-SS.
In truth, just the good-natured recollections of a young cockney lad from Southwark trying to do what he believed was expected of him… and hoping to make it home at the end of it.

Perhaps because of these stories, both their content and the way they were told to me, I have a true love of ALL shipwrecks that are casualties of war, and especially those who met their end as a casualty of WWII.

And over the years, I have been lucky enough to dive on scores of them, from the Bell Island Wrecks sunk in Conception Bay, Newfoundland, to the Japanese merchant vessels cloaked in living color at the bottom of Truk Lagoon, Micronesia. And in between, wrecks of Nazi and Allied shipping off the coasts of England, France, Nova Scotia, Scotland, the Carolinas, New York and New Jersey. Each wreck, war ship or merchant ship, a story to tell and I am simply glad that through some serendipity, I have the ability to listen.

I did not have the privilege to serve. My father convinced me that a spell in Her Majesty’s Armed Forces was not the best career path for me. Therefore, I have no special context, no special knowledge about how to organize the things these wrecks tell me.

I have simply marvelled at the destructive force of a torpedo while hanging in the water looking at the evidence of one exploding against a steel hull. A hole big enough to drive a London Bus through. The metal melted and twisted, the keel broken by shockwaves, any poor soul standing close by vaporized in an instant.

I’ve swum though holds filled with the materials of war: planes, trucks, explosives, ammunition, uniforms, food, a perfectly intact Sherman tank. All fascinating, all hugely interesting, and something divers like you and me have a special opportunity to visit.

During a trip “home” several years ago to spend time with family, my uncle asked me about the wreck of a U-boat I had recently been on. He wanted to know what class it was, the state of the hull, how it had been sunk, and the usual question about how deep it was.

After a barrage of questions, he finally asked if there were any members of her crew on board. There were and I told him so. He sat quietly for a few moments and then got up to make us a cup of tea. I was left wondering if the tears in his eyes were for buddies on his side of the conflict or for those German sailors who were trying to do what was expected of them… but who did not make it home at the end of it.

TDI Instructor Trainer: Steve LewisSteve Lewis is an active technical diver, instructor/trainer, expedition leader, and a long-time member of TDI. He currently works in the dive industry as a marketing and product consultant for clients in the public and private sectors. He is a successful author and is currently working on a new book about the history of cave diving entitled: Contributions.

Is Cave CCR the Ultimate Challenge in Diving?

by Steve Lewis:

rebreather in cave

As if cave diving isn’t challenging enough, how should we feel about adding a rebreather to the mix?

When asked, which happens from time to time, I’ll explain to anyone who’ll listen that the easiest way to really give your diving skills a workout is to enroll in a cave diving class. The customer feedback from folks, who take this piece of advice, and dive into a technical overhead program, usually makes extensive use of the words “humbling” and “embarrassing”. The phrase: “brought me down a peg” or something similar often makes an appearance too.

Cave diving, and to some extent Advanced Wreck Diving (i.e. wreck penetration), is fundamental to technical diving. Most of the information covered and the majority of skills and techniques taught in any technical diving program have their foundations in basic cave diving. The presence of a rock ceiling, rock walls, and a rock floor (often covered in a deep layer of fine-grained mud) tends to focus the mind and put a special meaning and strong emphasis to the sage advice that bailing out to the surface is not an option. As any technical diver will tell you, it’s very unwise to bolt for the surface on any dive, especially one that’s incurred a decompression obligation, but in a cave several hundred metres or feet from open water, that option is completely off the table. Problems of all shapes and sizes have to be fixed at depth.

One result of not being able to surface at will, is the cave diver’s conservative approach to gas management: specifically, carrying enough gas to get them and a buddy back to safety in the event of the most horrendous equipment malfunction at the back of the cave. The Rule of Thirds, the starting point from which cave divers traditionally begin their gas volume calculations, is the ubiquitous gas management technique adopted by virtually all technical divers.

Also, the techniques developed and refined by cave divers operating in North Florida and the Caribbean for communications, propulsion, equipment selection and configuration have to a great extent become the best-practice defaults for almost every technical diver around the world.

Furthermore, it’s long been accepted that the standards required for cave instructors (and their students) to earn their certifications to teach (or dive) in caves, are among the most stringent. Broadly speaking, the consensus is that cave divers and the men and women who certify them, are among the most meticulous and squared away of any group of divers.

So, what happens when we take the rigors of a cave diving course and apply them to a new program for which the core life-support systems have been changed from open-circuit to closed?

To begin any comparison, it’s fair to say that TDI’s training department and advisory panel thought long and hard about the best ways to evolve its successful cave diving curriculum to include the special needs of closed-circuit rebreather diving. I was not at head-office for the whole of the development process, but I know it was the work of a larger development team than any previous program. Which is hardly surprising given the magnitude of responsibility to “get it right” when combining the complexity of a rebreather with a supremely challenging underwater environment. Hardly surprising and somewhat comforting!

Given that, let’s look at what they came up with!

The basic shape of most cave courses is the same regardless of what type of gear the diver opts to use. The first step is Cavern Diver. Graduates from Cavern can move up to Intro-Cave Diver; and once that level is achieved are able to sign-up for Intro to Cave and Full Cave courses.

In the briefest of terms, cavern divers are severely limited in where they can venture; intro-cave divers have to stay on the permanent main line or gold line and are not allowed to make any jumps to side passages; and full-cave divers have a license to learn in most of the cave’s main and secondary passages.

The progression has stood almost unchanged since the first organised cave diving programs that pre-date the formation of most of today’s mainstream certifying agencies… in other words, it’s a progression that’s stood the test of time and held its value well. It then follows logically that TDI’s CCR Cave program follows this same structural paradigm.

I don’t think there’s any real confusion about where open water ends and a cavern begins: if you cannot swim straight up to the surface and fresh-air, you’re in an overhead environment. If the ceiling is wood or metal, chances are that you are inside a wreck, and if the ceiling is rock, you’re in a cavern.

There might be more confusion about the other end of the cavern and where exactly it turns into a cave.

The standard definition is that the primary source of light in a cavern is daylight. If you and I swim into a cavern and lose sight of the entrance and daylight, we have exited the cavern zone and entered the cave proper. And for the record, there are no caverns at night… and some cave systems do not have a cavern zone to speak of at all. (The Eagles Nest system in Florida as an example.)

That definition does not change for rebreather divers, but there is a subtle change that fundamentally sets up one of the challenging limits for overhead training on any CCR.

One absolute limiting factor for all open-circuit divers is the volume of gas they and their buddy or buddies are carrying. That volume (X litres or Y cubic feet) helps to define just how far they can travel into an overhead environment… given that they follow the established guidelines for gas volume management.

In TDI’s open-circuit (OC) cavern course, penetration is limited to one-third of the volume of a single diving cylinder or one-sixth if the divers are using double cylinders. This is somewhat further defined to explain that the available volume for penetration for the whole dive team is set by the team member with the smaller cylinder or who has the smaller(est) starting volume.

The same volume limit is suggested for OC intro-to-cave graduates.

This limit very effectively helps to “police” or control new cave divers’ return access to open-water and safety. Since running out of gas is #1 on the list of things to guarantee a cave diver is going to have a bad day, the one-third in a single / one sixth in twins guideline goes some way in keeping new cave divers from venturing too far into the cave.

But a fully functional CCR does not have the same sort of built-in restriction. Certainly both diluent and oxygen supply is limited but those limits are measured in hours rather than minutes.

Let’s take the oxygen supply as an example. (Forgive the use of SI units but cubic feet are more complicated and unnecessary to get the point across. If you are only used to American Customary Units, just think of litres as quarts.)

We’re taught that the average per minute oxygen consumption rate for a diver is 1.5 litres. This volume is depth independent. And unlike their OC breathing brother and sister divers, for a diver on CCR, it really makes little difference whether the consumption is measured on the surface or at advanced trimix depth. One’s consumption rate will vary a little with workload, but 1.5 litres makes a pretty good average to work with. For now, let’s make life simpler and a tad more conservative, and use a consumption rate of 2.0 L/min. This is really quite high, but two litres a minute makes the arithmetic even easier than it would be at 1.5.

Now the smallest rebreather tank in common use has a wet volume of about two litres. That means every full atmosphere of pressure in that tank equals two litres of gas. In other words, a fill of 200 bar means there are 200 X 2 litres of gas. That’s 400 litres of gas. Quick math… at two litres a minute consumption, this volume of gas will last up to 200 minutes!

Even if we follow a sort of rule of thirds and suggest a CCR diver only use one-third of his or her starting volume of oxygen, one third of 200 minutes is more than an hour.

This means that if a beginning CCR cave diver follows the same gas rules as an OC diver, he or she can swim into the cave for an hour before having to turn the dive on gas volume! An hour of swimming into a cave usually translates into about an hour swimming out. Sometimes the flow helps to make an exit a little shorter, but an hour would be a fair estimate.

I think even those of us who have zero cave experience will begin to see the potential for a huge problem with this scenario.

If we were to line up the special concerns of those who teach CCR cave diving, at the front of the queue would be: a rebreather is essentially a potentially wicked cross between a time machine and a gas extender. What makes it potentially wicked is that compared to the classic North Florida set of twin steel tanks (even the big ones) the most inexperienced diver can wander deeper in to a cave system… much deeper than he or she should. If something bad happens, an hour is a long swim nursing a problem.

The “magic bullet” designed to help avoid this type of event centers on bailout gas.

Bailout gas is what a CCR diver carries for contingencies. Should the rebreather become completely inoperable, then they stop using it and start breathing from a tank of compressed gas using a scuba regulator. In other words, they fall back on good old-fashioned open circuit.

Some time is spent in the foundation dives for cavern and intro-cave CCR programs working out how much bailout gas each diver must carry, and how far from the surface that gas allows them to venture.

The calculations for this distance are based on a consumption rate effected by a carbon-dioxide breakthrough on the rebreather. A breakthrough such as this would probably result in a diver breathing like a racehorse on the final furlong of the Preakness. Therefore, the calculations are conservative and the guidelines they offer for penetration are written in stone: a sensible diver would never dream of compromising his safety by ignoring these guidelines.

Is your head spinning yet?

The truth is that the task loading for a student taking a CCR Cave class is really high. In addition to the gas management “thing” they have to master all the skills expected of an OC cave diver. They have to run line, place line markers, read the cave, overcome current, learn navigation, perform lost line drills, lost buddy drills, show their instructor perfectly executed bottle swapping in zero vis, and prove they can swim without kicking up a curtain of silt. And when that’s finished, they need to come up with strategies for rebreather-specific issues. They have to run their CCR manually, in SCR mode, they have to deal with depleted diluent, low oxygen, stuck solenoids, and a raft of other “fun” challenges!

Is your head spinning now?

The truth is that I dive CCRs in caves by choice. I believe that all things being equal, a rebreather is the right tool for cave exploration eight times out of ten. (Sidemount covers the other 20 percent!) Like so many high-risk activities, the pay-off is high-value. It’s also a class I love to teach because it is such a challenge and students walk away with a justified sense of accomplishment.

Is Cave CCR the ultimate challenge in diving? I know Brian [Carney, president of TDI] and the team in TDI’s training department well, and I am sure they have other cards up their sleeve; but as it stands, I cannot think of another program that tests a diver’s mental and physical stamina more than this course.

Is it fun? Yes it is. Is it useful? Certainly. Is it tough? Sure thing. Should you start planning to challenge yourself? Well, I don’t know if you’re ready but if you think you might be… Go for it!

Ice Diving for Fish Hooks

By Steve Lewis

When I mentioned to a friend that I was writing a short article for TDI about diving under ice, she asked where I’d be writing about. She has known me long enough to have heard about “cold-water adventures” happening under pack ice around Baffin Island and Sirmilik National Park in Canada’s far north, iceberg diving off the Atlantic coast of Newfoundland, and ice-wreck diving during the long Great Lakes winters.

I told her the locale was far closer to home. “They asked me to write about the most fun I’ve had ice diving,” I told her. “SO, I’m going to write about diving in a small pond during Winter Carnival in the local village.”

She asked, why nothing about the amazing upside-down cathedral-like spires of sea ice that glow as top-side sunshine fractures into a thousand different shades of blue and sapphire? Why no mention of an ocean floor thick with sea anemones, sea stars, isopods, and a million different creatures living below a solid roof of ice? And wasn’t I going to mention catching glimpses of walrus and narwhales at depth, or the interaction of great seals checking you out and trying to chew strobe lights and dome ports off cameras? Oh, and no mention at all of polar bears “upstairs” playing cat and mouse with your surface support… them the cat, tough guys weighing in at 240 pounds relegated to the role of mice! Nope, none of that and nothing at all about diving on giant icebergs stuck fast in the sea floor 30 to 40 metres below the surface and offering the most spectacular swim-throughs imaginable.

Instead I wanted to explain why one of my favorite memories of ice diving took me to a three-metre deep muddy bottomed lake in the middle of rural Ontario during one of the coldest winters on record… almost as cold as the one we are suffering through right now.

But first, some explanations.

Diving under ice may sound odd especially if you are a diver who has only experienced coral reefs and blood-temperature water. Well, actually, it is a little odd no matter what your background. When diving requires a chain saw and steel pike to cut holes in the solid ice covering a lake, river or ocean, we are clearly not talking about run-of-the-mill scuba.

Ice diving is different. It requires specialized training, equipment that is not to be found in every dive shop, and surface support that must pay attention and take an active role during the dive.
However, ice diving is an attractive and uniquely exciting experience. Visibility under ice, whether in the Arctic or a local quarry, is typically excellent, and made more majestic by soft light filtering through layers of ice from the world above.


Ice diving covers many types of environments – the ocean, lakes big and small, even rivers and spots where ice floes may be present rather than solid ice. In marine environments especially, the aquatic life you encounter can be stunning. Often overlooked, cold-water diving can offer the very best subjects for photography and video. Visibility is often stunning too. Ice provides a protective layer so that wind does not whip up the surface (no seasickness!) and with water temperatures hovering between 0 and four degrees C, and low light levels, algae growth is inhibited.


Ice diving, just like cave diving and advanced wreck diving, is conducted in a true overhead environment, and it too requires special training. One critical thing to understand is that the techniques for cave, wreck and ice – while sharing some common concepts – are different enough that being proficient in one does not prepare you to dive in another. This is especially true of ice diving since not only is ice diving overhead environment diving, it is also carried out in extremely cold conditions that require special attention to issues that are not relevant when diving wrecks or caves.
An SDI ice diving course will teach you the safety aspects of diving while tethered on a rope under ice, but also how to cut the ice hole through which you enter the water, and how to tend safety ropes for other divers while you remain on the surface in a support role, AND how to prepare your regulators for performance under the ice.

Here are a few of the major differences. Generally speaking, safe ice diving requires a minimum of four people per dive: two divers operating as a buddy pair, and two people to tend their lines.
It is even better (read: it offers more security) to have at least one extra person geared up and on standby ready to get into the water in the case of an emergency. It is also standard practice for each diver to be tethered separately, and to have their own line tender, and is not recommended to have two divers attached to one line. Divers attach lines to a webbing harness with locking carabineers and a bowline knot, much the same as rock climbers.


Being able to communicate with your line tender – the person attached to the other end of your tether line – is an important part of ice diving. Since you are diving in extremely challenging conditions, it is critically important that he or she knows you are doing fine throughout the dive, and if that is not that case, that you need help. During an ice diving course one learns about giving clear, non-ambiguous rope signals. You do not want someone to start hauling you in like a large trout when you are in the middle of getting that perfect nudibranch photograph.
Apart from the obvious dangers of diving in an overhead environment, ice divers must also be careful to monitor their core body temperature both beneath the surface and during surface intervals. Often, the coldest part of an ice dive is the time between dives! Repeat dives should only be undertaken when one is completely comfortable and fully warmed up. One surface-interval trick is to eat high-energy, hot food to replace one’s energy levels.


Ice diving requires special equipment. To begin with, one needs a regulator that will function correctly in extreme cold. This usually translates into an environmentally sealed regulator set, which is designed specifically to be less susceptible to freezing and resultant free-flow of gas.
As well as being environmentally sealed, ice divers also only breathe from their regs when submerged since water – even freezing cold water – may be actually warmer than the surrounding air… especially when the wind is blowing.

Most ice divers also carry some type of redundant gas source. This may take the form of a Y or H valve on a regular single cylinder, a set of twin tanks, two sidemounted tanks or a single cylinder with a pony or stage bottle.

And while some brave souls have been known to ice dive in wet suits, most opt for drysuits and warm underwear, a thick hood, and dry gloves. Even those on the surface tending lines need to be protected. Thick anoraks, caps that cover ears, non-slip, water-proof shoes, and decent gloves are standard. So too is some sort of wind-break or screen, and in really top-flight, well-organized, and deluxe expeditions, a warming hut that sits on top of the diving hole!


Actually, an SDI ice diving program will also introduce divers to gas management procedures, kit failure procedures, personal health and fitness issues and plenty more. It can be a challenging program, but really worthwhile because ice diving does present some unique opportunities to experience diving in a totally different light, as it were.

Which brings us to my story about my best ice dive, and as mentioned, it was not in some exotic locale, just the local village during Winter Carnival. One of the guys in a service club in the village was an ice diver and he suggested something a little different as a fundraiser. For a donation, kids would ice fish and catch numbered tags. Each tag won a small prize… a toy, a gift coupon, a cup of hot chocolate. Our job was to gather around the “fishing holes” wait for “hooks” to appear – actually the hooks were small clips similar to the ones on novelty key rings – and load them up with the tags… then give ‘em a tug.

The effect was priceless. The only issue we had was keeping up with demand. As soon as youngsters saw their friends landing “fish after fish” there was a lineup!
Great fun, great idea, and seeing the look on kids’ faces, priceless.

The diving appeal of the Bell Island Wrecks and Iron Ore Mine


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

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

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

So, what about those wrecks? Just outside of the city of St. John’s in the middle of Conception Bay sits a small blob of land called Bell Island, and Bell Island had a very productive mine that exported iron ore to steel mills in several countries including those in Cape Breton, Canada. At the outbreak of war, these mills a little to the south in Nova Scotia, accounted for about a third of Canada’s steel production. With shipments from the Bell Island Mine to German factories cut off because of the war, it was inevitable at some point that the Germans would attempt to interrupt production and throw a “spanner in the works” for the Allied war effort. And interrupt they did.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The questions they wanted answers to where simple: can it be dived? Is it interesting enough to attract divers? Are conditions supportable for regular visitors? There were some side issues that needed to be addressed, but the hope was to open up a unique form of adventure tourism for the island and its economy. With a background in Tourism Marketing, I was certainly curious enough to take Rick up on his offer and set about building a team that would be able to pull things off. After a simple exploratory dive in July of 2006, we set a target date for the following January/February, and started planning.

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

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

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

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

During the following two weeks, the team surveyed the mine looking for any evidence of cave-in or collapse in the mine shaft and laid permanent guidelines from the surface along the main shaft to a depth of approximately 30 metres. The seam of iron ore slopped at an angle of approximately ten degrees and continued many thousands of metres under the overlay of ocean floor below Conception Bay. In addition to the main line, four ‘jump lines’ were laid in side passages. The initial plan was to extend these side passages (roughly horizontal) approximately 300 metres east and west of the main shaft. Overall a total of 2km of line was laid in the mine.

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

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

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

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

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

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

The Team: Rick Stanley, Debbie Stanley, David Sawatsky, Phil Short, Ralph Hoskins, Vlada Dekina, Dave Clemmens, David Powell, Mark McGowan, Stephen Phillips, Aaron Bruce, Mike Fowler, Joe Steffen, Steve Moore, Susan Copp, Steve Lewis

article by Steve Lewis

Contact SDI TDI and ERDI
If you would like more information, please contact our World Headquarters or your Regional Office.
Tel: 888.778.9073 | 207.729.4201
Email: Worldhq@tdisdi.com
Web: https://www.tdisdi.com

Cave Diving and the Dangers without Proper Training

Sidemount Diving: It’s Not Just for Caves

By Steve Lewis

Sidemount-Diving-Not-Just-for-caves… but we should remember, that is where it started!

Perhaps typical of divers who use and teach sidemount today is the phrase, “it’s not just for technical divers anymore!” And the truth is that sidemount is a truly versatile kit configuration that in the past few years has stormed into just about ALL areas of technical diving (even rebreather divers side-mount their bailout bottles!), as well as gaining favor with sport divers who have no intention of pushing ANY limits whatsoever. However, it’s worth remembering that for all the flexibility and adaptability that sidemount configuration offers to tech and sport divers, it started as some weirdness that only crazy cave divers got up to.

My personal introduction to “sidemount” was as a kid dry-caving in the UK. We were not divers, but we had access to small cylinders filled with air – probably three or four litre steel tanks about the size of the bottles you’d find on most rebreathers these days – and there were a couple of short sumps between us and the best parts of the caves we were playing around in. We strapped a tank to the side of a climbing harness, put the regulator in our mouths, and walked/crawled through the sump. And believe me, the reality was a lot less dramatic than the description. The sumps – a part of the cave completely underwater – were probably no longer than we could have covered holding our breath, and the cave we were exploring, at least the part we were exploring, was a very well-travelled passage. Nothing at all note-worthy.

The point being that if we’re looking for the spot to place a commemorative plaque celebrating the beginnings of sidemount “diving” in caves, we could easily argue for the Mendip Hills, in England’s West Country. In fact, that area has been – and remains – the focus for “real” cave diving and true exploration since the late 1930s.

But, if the birth of sidemount cave diving took place in England, the technique was raised to adulthood in the area of North Florida famous for its karst landscape, fresh-water springs, pioneering explorers, and organized clubs and associations promoting ecology, preservation, understanding, and formal dive training.

Within a generation, SM (sidemount) cave diving, as taught and promoted in Florida’s cave country, has evolved from a somewhat marginal extreme undertaken by a tiny percentage of trained cave divers, to a level where today, in some systems, close to 100 percent of the divers playing in the cave are configured in sidemount gear. In short, it has grown to the point where the question, “Who does that crazy stuff?” seems to have morphed into, “Who isn’t doing it?”

So, if we know who – everyone or close to everyone – let’s find out why and how.

Why use SM in a cave? Well, the traditional answer would be that a sidemount configuration allows a diver access to areas that would simply not be open to them if they carried tanks on their back.

Configured correctly, SM gear is extremely streamlined: that is, when hoses are optimal lengths, nothing is left hanging off the diver to simulate being a Christmas tree decoration, and primary bottles run along the diver’s lateral line without their noses pointing to the floor and their backsides in the air. The diver’s in-water top-to-bottom profile is much smaller than when wearing doubles, a single or a rebreather. It’s true that her side–to-side profile will be wider (incidentally giving a very comfortable lateral stability), but the way sidemounted tanks are attached to the diver’s harness allows them some latitude to move out of the way when side-to-side space gets restricted.

Indeed, a skill taught to SM students, during even a very basic orientation class and certainly in a SM cave diving program, is to unclip the rear snaps and swing one or both cylinders around so that while the tanks nose remains attached, the bottoms now face forward. This gives the diver a very long, narrow profile.

In short, for smaller, tighter spaces, sidemount rocks.

By the way, this last technique is NOT no-mount diving. No-mount is an extremely advanced technique used to explore very tight passages. The diver pushes a SINGLE, unattached cylinder ahead of them through small passages. Doing this offers access in very limited space, but is hugely risky for several reasons, not the least of which is that the diver has zero back-up gas and may have to exit without being able to turn around. For the record, John Chatterton famously used this technique to explore the U-Who wreck.

A lot of sidemount’s popularity is due to the wide-spread availability of purpose-bought SM harnesses. In sidemount’s adolescent years, sidemount cave divers used stab jackets (traditional sport BCDs) as the core of their SM kit. These were highly modified with bungee, bolt-snaps, sewn loops of webbing and added DRings to the point where when modifications were completed, the end-result was barely recognisable as a shop-bought piece of sport diving kit.

This DIY approach certainly seemed to restrict the growth and popularity of sidemount diving. A change came when mainstream equipment companies started to sell integrated wing and harness rigs custom-designed for sidemount cave diving. The leader on this score was Dive Rite, a cave-oriented manufacturer based in North Florida but with distribution world-wide. Currently, Dive Rite sells several models of SM harness each designed for a slightly different purpose and are probably the best-known and most popular SM brand. But they are no longer alone, and several other companies have one or two models on the market including Hollis, Oxychek and OMS.

This sudden explosion of available, well-built, purpose-designed harnesses – and the accessories such as CAM bands and various length LP and HP hoses that make rigging for SM much less of a DIY project than it was just a handful of years ago – has helped fuel the growth of SM cave diving. But there is certainly something else at play.

Lamar Hires, president of Dive Rite, describes it as a life-style choice. “Using SM to explore tight spaces is a mission-specific decision,” he says, “But a lot of divers are uncomfortable carrying a set of double cylinders, and for them, SM offers a lot less stress because cylinders can be carried to the water one at a time!”

And a straw-poll of a lot of SM cave divers turns up that the number one reason for being configured the way they are is convenience and comfort, rather than something “mission specific.”

The ‘HOW’ of SM cave diving is what’s taught in a TDI Sidemount Diver course. Most of the techniques and procedures are the same as a “regular” cave course with kit configuration being one major difference. Another is the slightly more complex system employed to manage gas volume. With two independent cylinders as opposed to two cylinders joined by an isolation manifold, the diver has to switch regulators during her dive to distribute gas consumption “evenly” between each tank.

In all TDI overhead programs, the Rule of Thirds and related modification of it are hammered into students’ minds with constant repetition. The simple mantra of “one-third in, one-third out, one-third (plus an additional reserve) for contingencies” holds true for SM cave diving, but there is a twist on account of the need to swap regs during the dive.

There are a couple of protocols that are taught but one that is popular goes like this:

Given that gas-matching and volume requirements are worked out and agreed with the rest of her team, the diver begins her dive breathing from Tank A. When she has consumed ONE SIXTH of her available volume, she switches regs and begins to breathe from Tank B. She continues to breathe it until she has consumed ONE THIRD of her available volume, at which point she switches regs once again. She is now back to breathing from Tank A. When she has consumed ONE SIXTH of its volume (which adds up to a total of ONE THIRD of the available volume in EACH cylinder), she signals turn the dive. But she keeps breathing from Tank A until she has used an additional SIXTH. At which point she switches regs for the last time. Let’s use some simple numbers to illustrate the point (and we’ve avoided using pressures or actual volumes to make this work for both imperial and SI unit users, and the asterisk indicates the tank being breathed from).


Using this technique, the difference between the two tank volumes during the critical phases of the dive are never more than one-sixth of the starting pressure. In the event of an OOA situation at the maximum penetration, the OOA diver can be given a cylinder containing 2/3 of the starting volume… enough to get them out if proper gas management rules are followed. As the exit progresses, the gas buffer, the contingency, gets wider and wider. Using this method, there are only three regulator switches. Most other options require more.

Obviously, there’s much more to be said about SM cave diving – that’s what a course is for – but we hope this has at least reminded you where the SM “craze” started: wet rocks and holes in the ground, like so many of the innovations in diving today!

Have fun, and dive safe.

Below are a few of the TDI sidemount/cave courses offered.
TDI Sidemount Diver >
TDI Cavern Diver >
TDI Intro to Cave Diver >
TDI Full Cave Diver >

Contact SDI TDI and ERDI

If you would like more information, please contact our World Headquarters or your Regional Office.

Tel: 888.778.9073 | 207.729.4201

Email: Worldhq@tdisdi.com

Web: https://www.tdisdi.com

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