TDI™ Releases Course Standards for GEM Level One Diver Course

Keeping with the latest in technology and the demands of new diving adventures and equipment, Technical Diving International (TDI) has released the course standards for the TDI Gem Level One diver course. TDI worked closely with KISS Rebreathers to get these completed. Kim Mikusch of KISS Rebreathers stated, “We are very pleased to have worked with the professionals at TDI in the developing of the KISS GEM training course.”

“For years there has been a void in the rebreather market for a semi-closed system,” stated Sean Harrison Vice President of Training and Membership Services. He went on to say, “I think the new GEM will meet the needs of divers looking for a way to extend their diving times and reduce the noise without going the fully closed circuit route.”

The TDI KISS GEM Level 1 Semi-Closed Circuit Rebreather (SCR) course is the ideal course for photographers, cold water divers or anybody wishing to enjoy a quieter dive and closer interaction with marine life. The course is unit and level specific covering the GEM Level 1 skills and academics. The GEM is an SCR that can be attached to any size cylinder within minutes and ready to go for a 2-4 hour dive (times water temperature dependent).

Many TDI™ Instructors and facilities have been eagerly awaiting this latest announcement from TDI™ Headquarters and are eager to get started with their programs.

To find a program near you please visit or call 888.778.9073 or 207.729.4201

On the “Road” Less Traveled with Technical Gear

On the “Road” Less Traveled with Technical Gear

With the right approach, traveling with a Rebreather may be easier then you think!

Few, if any, dive destinations are able to provide the experienced tech diver with a complete list of rental gear. It is simply impractical for a resort — even a tech-friendly one that is part of the TDI family — to underwrite the sort of inventory that would satisfy all the needs of customers whose idea of what constitutes the “right kit” covers a broad spectrum of equipment from numerous manufacturers.

Most of the techies I know will drive a vehicle packed with their own kit whenever possible, and when flying is the only option, will pack one or two articles of clothing and use up the rest of their baggage allowance transporting their own dive gear.

The situation is more critical for CCR divers, especially those whose travel plans start at an airport security line-up.

The special challenges for a CCR diver include unit specific training and certification; a diver can only use the machine he or she has experience diving with and other machines are off the menu without an additional orientation program.

This effectively means that rental CCR units at one’s destination are an unlikely option. At several thousand dollars/pounds/euro a pop, CCRs represent a huge investment for a dive shop’s rental department; offering more than one or two types or models is rare. The bottom line is that the vast majority of divers will take their personal CCR on vacation with them because there is NO rental unit available. Even in the cases where there is a rental available, many CCR divers prefer to take their own unit – It’s a comfort thing.

Some CCR units are compact and use up only a portion of a diver’s baggage allowance. Others accrue excess baggage fees right from the outset. Also, several units require specific cylinders and or valves which translates into yet more weight.

Quite apart from the logistical challenges of packing a CCR, cylinders (which MUST have the valves removed), CO2 scrubber material (we suggest shipping well beforehand), regs for bailout bottles, and the required assortment of spare parts and supplies for a safe and happy dive time, there are some other issues worth considering.

The first is that a rebreather – especially the unit head – can simply look weird when viewed through an airport scanner. I have had luck with CCR and dive lights, to the point where the x-ray tech has piped up “who is the cave diver?” when my carry-on has been travelling on the belt. But this is the exception. Expect to have to explain what you are travelling with.

Here are some suggestions with regard to that challenge.

When I travel with a rebreather, I create a “This is life-support” document. It is a simple statement on headed note paper with every attempt to make it look as official as possible. The document states that the equipment is scuba gear. That it is safe for travel and conforms to airline guidelines. It explains that the scrubber head contains electronics (if it does) and gas sensors (I am careful to avoid ANY mention of oxygen based on past experiences dealing with people in authority who failed high-school chemistry). It states that there is no compressed gas, no harmful liquids or chemicals: just the business end of a couple of regulator first stages and some tubing.

The first time I used it (a few years back) the TSA agent I presented it to said something like: “Oh, we’ve seen these before” and I was cleared in minutes.

The other “trick” that seems to work is wrapping some portion of the unit in a wetsuit or with something else that screams out DIVE GEAR. There seems to be nothing quite as reassuring for someone faced with this mysterious lump of kit as something they recognize. What works is giving the folks checking your kit an opportunity to guess what the heck it is. Most of all, take the time to explain to them what it is you are going away to do, and be polite (Public Relations 101!).

A buddy of mine was called back to security at a US airport (Honolulu) to explain his checked baggage, which contained – among other things — his scrubber packed complete with its head and stuffed with Tshirts and underwear. It seems the tech searching the bags thought it was a scuba cylinder containing compressed gas and the handset was a pressure gauge. When confronted, my friend said, “hey, that’s an understandable mistake…” rather than “NO, you’re wrong!” The final outcome? He was back in the lounge drinking coffee within a couple of minutes and his baggage made it the rest of the way to Truk Lagoon.

You, too, may have read horror stories about trying to get through customs with scrubber material, which for those who are unfamiliar with it, is a white powdery material. I have never tried it and will probably never attempt it anytime in the future. There are several shipping options that, to me at least, seem more reliable and less costly. If there is no sorb available where you are heading – which with the growing interest in CCR is becoming less and less common – using FedEx, UPS, DHL or another reputable company can be the best alternative.

Start the shipping process early and ask about duty and import taxes before committing, and in some destinations, be prepared to pay a little extra for “handling fees”.

All in all, airline travel with a CCR is more complicated than traveling with OC gear, but with a little pre-planning, it is manageable and the more you do it, the easier it becomes.

Some Tips for Travel with CCR

  • If the option exists, use Rebreather friendly operations – resorts or live-aboards with CCR supplies on hand and experience working with CCR divers (Ask SDI for a list of CCR friendly operations around the globe.)
  • Arrange for oxygen fills (with booster if possible) at destination, explaining that this is critical.
  • Wherever and whenever possible, arrange for Scrubber medium to be ready for your arrival. Even at a rebreather friendly destination, book what you need, plus some contingency sorb well in advance of your departure. If in doubt, ship your own but do research on local import and tax/duty requirements.
  • If possible, rent bottle for diluent and oxygen. Check they are the correct dimensions and that the valves will fit your regulators.
  • Arrange for “bailout” bottles at your destination. Aluminum 80s work well but take your own rigging hardware AND check if the valves are DIN or Yoke. (The issue of left and right hand turn knobs is less of an issue and these are items that you can carry yourself if needed.)
  • If you are traveling with your own oxygen and diluent bottles, remove valves and leave bottles open… this means not even tape should be covering the open neck.
  • Remove oxygen stickers from bottles and reapply at your destination.
  • Pack “This is life-support” document with unit and carry several spares.
  • Be ready and willing to explain your kit to airport security personnel.
  • Be patient!
  • Learn to make do with a minimum of fresh clothing!
  • Have fun!!

When it comes to Tech Training NO ONE has your back better then TDI™. No matter where your spirit moves you when it comes to Tech there is a course for you.

Explore this site and see where your quest for knowledge takes you next!


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Sport vs. Tech

Equipment needs certainly vary, but the adventure is always a constant!

You have probably seen the illustration:

One diver is covered in gear. He is in a drysuit, has a pair of twin cylinders on his back, a stage bottle strapped to his left side, one regulator second stage hanging from a shock-cord necklace, two bottom-timers on his wrist and an assortment of “accessories” stuffed into pockets or occupying what little real-estate is left on his two-inch wide simple webbing harness. He has a serious “all business, no fun” look on his face – A look that reminds me of the expression worn by the male models in old Sears mail-order catalogs in the sixties and seventies.

The other diver is standing in what looks like a 3 mm wetsuit with a stab-jacket, aluminum 80, and a smile on his face.

I have never completely understood the purpose of this drawing (is it to warn people about technical diving?). What I do know, however, is that it has been the source of a lot of questions from perspective students for tech programs over the years, especially candidates for TDI Intro to Tech (I2T) classes who usually ask, while pointing to Mr. Serious, something to the effect of: “Do I need all that stuff to do this class?”

The answer of course is a resounding no! The gear requirements for taking part in an I2T class can be more or less the same as for regular sport diving, but there are a few notable differences between the type of gear used by the average sport diver and the choices more commonly found on divers who venture into technical diving. Understanding what they are, is a good first step towards understanding what tech diving is all about.

One of the first major differences is exposure protection. A simple definition of the difference between tech and sport diving is tech equals more bottom time. Since it boils down to more time on the bottom, staying comfortable and warm takes some additional care, especially in regions with a thermocline!

Technical dives also often include a slow ascent with more than one stop on the way back to the surface. Partly because of this, many techies diving in cool to temperate water opt to wear a drysuit and pay particular attention to thermal protection for their core and extremities.

Of course, a drysuit is no definitive indicator that a diver is a techie because plenty of divers who have no desire to venture “deeper and longer” invest in one. A drysuit is often favored over a wetsuit for both additional warmth and more controlled buoyancy characteristics. (Remember that neoprene compresses as depth increases and therefore you can almost read the Sunday paper through a 7 mm wetsuit at 60 metres [200 feet].)

Perhaps the most noticeable difference is the number and size of scuba cylinders a technical diver carries. It all relates back to the first rule of scuba: Keep Breathing.

At great depths, making sure you have enough gas to keep breathing usually calls for a lot more litres or cubic feet than can be squeezed into a single cylinder. Couple this with the practice of optimizing off-gassing during ascent (that’s a fancy way to say breathing nitrox on the way up) and our tech diver now has to carry one or more cylinders filled with decompression gas.

A more subtle difference is regulators and the way they are set up. First off, technical divers tend to be very specific about which make and model of regulator they buy (and remember, they buy a bunch of them for all those tanks they carry!). The primary reason is a need for high-performance and a piece of kit with the ability to deliver large quantities of gas at depth. Consequently, tech divers tend to shun regulators that are perfectly fine for a warm-water reef dive to 30 metres / 100 feet, and opt instead to pay top dollar for regulators designed to minimize work of breathing.

Another factor in the quest for the perfect regulator is the routing of the hoses coming from the first stage. The goal is to find a design which keeps low and high-pressure hoses as streamlined as possible. Tangles and big loops of hose coming out from a first stage, looking like the arms of an octopus, are not cool in the tech arena.

This requirement further thins out prospective brands. Final choices for regulators on primary bottles as well as deco bottles or stages often come down to three or four brands and specific models within those brands.

One last difference for regulators is that they are DIN verses yoke. Tech divers use DIN because the connection between the tank’s valve and the first stage is more solid and the Oring keeping things gas-tight is trapped. A yoke first stage is far more likely to become unseated than a DIN valve, and I have seen – very recently – a yoke regulator blow off a stage bottle below 200 feet after the mildest of taps against a rock wall during descent. Not a reassuring sight.

Instrumentation is usually very different too. Techies carry depth gauges/bottom timers and or dive computers on their wrists rather than in a console, and they usually carry more of them. It is not unusual for the one integrated personal dive computer carried along by an SDI open water diver to be replaced with two multi-gas, multi-function computers or a computer backed up with a digital bottom timer and a set of tables cut with proprietary PC or Mac based decompression software. The hottest and latest technical dive computers are capable of programming for as many as ten different gases, track decompression obligation second by second, download graphics seamlessly to a PC or Mac, and can have software updated by connecting to the internet. Some even help pass the time during decompression by allowing divers to play simple video games. We have come a long way from a bourdon tube, baby!

Other “stuff” that you may find very different on the average techie are accessories and how they are carried. Sheer volume dictates carrying accessories differently, and a need to streamline and lessen entanglement potential also means that pockets, pouches and bolt snaps are de rigueur. A quick inventory includes an underwater notebook, DSMB (delayed surface marker buoy) and spool, a spare low-volume mask, backup bottom timer and depth gauge, spare cutting devices and backup lights.

Now this is not to suggest that a tech diver takes everything he or she owns into the water. There are pretty well-established guidelines that dictate only taking what is required by the dive plan, but if that plan does call for something, it has to be accessible as well as functional.

This brings us to one other important issue for all tech gear: It is serviced regularly, inspected and tested before every dive, and replaced if found defective. There simply is no room for any piece of equipment lashed together with string, bailing wire or duct tape on a technical dive.

So what are you waiting for? Find a TDI facility of your own and embark on a whole new adventure! /index.php?did=16&site=2

We Are Outta Here

When to call a dive: the definitive guideline to no-fault bailout

There are plenty of things that the technical diving community has borrowed, begged or stolen from the North Florida cave diving community. The list includes the use and routing of a long hose on one’s primary regulator, gas management protocols such as the Rule of Thirds, the now common pre-dive S-Drill and Bubble Check, and even the basic backplate, wing and simple webbing harness configuration that seems to be the default for techies (and a growing number sport divers) the world over.

However, one item that has probably helped the diving community at large avoid more mishaps than any other is what originally was called the “Cave Diver’s Credo,” also known as thumbing a dive or the preferred, no-fault bailout. You may see it written in textbooks as: ANY DIVER can call ANY DIVE for ANY REASON at ANY TIME without fear of REPROACH or RETRIBUTION.

This phrase may strike you very differently, but to me it sounds a little as though it was written by a legal assistant trying to win brownie points. The parking lot version goes along the lines of: “Any time during our dive you ain’t comfy, y’all thumb the dive! We can go drink beer instead… I got no problem with that at all!”

My guess is that the majority of technical divers have pulled the plug a time or two during a dive (or even BEFORE a dive) and been thankful their buddy or buddies, subscribed to “The Credo.” I know I have. And of course, the converse is true too. I have been ready to rock and roll only to have a dive mate call it all off in a heartbeat. No worries. No questions. No nasty remarks as the gear is packed away and we head for home (or to the nearest pub with draft Guinness and pulled pork sandwiches).

As a matter of fact, one of the qualities many experienced technical divers look for in a team member is that they fully understand and agree with the whole concept of no-fault bailout; and the related issues of risk identification, assessment, avoidance and management. It helps keep everyone healthy!

When aspiring technical divers first learn about this concept, there is usually some debate about what reasons constitute calling off a dive. And in fairness, the question deserves a more complete and specific explanation besides the generic response: “ANY REASON.”

Since we recognize where the concept of no-fault bailout comes from, it seems logical to conclude that it developed because of the very nature of caves. A solid overhead environment – with no quick and easy access to the surface and fresh air – brings with it by default a whole new respect for pre-dive checks. It shouldn’t be a surprise to learn that in an environment as unforgiving as a cave, the number of checks increases and the diver’s attention to them is more focused. There is simply no room for compromise and no place for “well, that’s good enough for now” attitude. And all this translates seamlessly for ANY form of technical diving, whether in a cave or someplace else.

The easiest way to explain this to the newly-minted technical diver is to point out the focus on equipment and gas checks. These include inspecting hoses for leaks or strange kinks and poor connections; inspecting harness webbing and wing for nasty-looking abrasions or weak spots; checking and pre-breathing regulators; working valves and inflators to make sure they operate the way they should; making sure every cylinder of gas is analyzed, tanks are marked with MOD (maximum operating depth), and each tank is cross-checked with the dive profile and our buddy’s gases. The list continues with divers working out to the most exact amount of volume each gas required for each phase of their dive, including the additional gas required for contingencies like a massive leak in the buddy’s primary cylinder or deco. The last step is running through visual and tactile checks on accessories like primary lights, back-up lights, bottom timers, wetnotes, spare masks, bolts, snaps, straps and so on. Of course, anything not 100 percent has the potential to cause the dive to be called, postponed, or modified. And, all this is checked BEFORE anyone even gets their face wet!

More difficult to explain is the whole concept of comfort zone and personal stress assessment. These topics alone could form the outline for a complete dive book, but the Cole’s Notes version is that panic is about as welcome at depth as a lit cigar is in a fireworks factory. Panic and everything that leads up to it has to be well-managed by all divers; but most especially for divers who do not have the luxury of a direct and clear path to the surface.

For the most part, panic can be avoided by following a few simple guidelines: do not exceed your level of training and experience; increase the scope of your diving by small increments; never allow yourself to become so task-loaded that you lose the plot; watch your depth; plan to avoid surprises but be ready to deal with them; and never succumb to peer pressure.

If one follows those guidelines, managing panic becomes a learned skill. One of my favorite illustrations is a quote from Bill Hogarth Main. Bill is a cave diver/guide and lends his name to the minimalist approach to gear configuration and dive prep so popular (and so misinterpreted) with a whole raft of divers who have never been in a cave or heard of Bill Main. He said when asked about panic and its control that “it is worth understanding that a piece of dive equipment breaking underwater is unlikely to kill you… but your reaction to it could be disastrous”. Experience breeds a cool head and a cool head is a very useful tool when a dive goes off the rails.

And of all the dominos that can fall and start off the chain reaction that could result in diver panic, perhaps the most insidious is the trust-me dive. The classic “trust me” dive is one where a diver or a group of divers are pressured into doing something they have no business doing because their bolder, fool-hardy dive buddy says something like: “Don’t worry, I’ve done this dive a thousand times… trust me on this.”

These two little words – trust me – have gotten heaps of otherwise sensible, caring, intelligent men and women into the nastiest, tightest, most dire situations imaginable. If you hear those words as part of a dive briefing, drop everything and run for your life! They mix about as well as oil and water.

In the final analysis, the right time to call a dive is as soon as something breaks or stops working the way it should. I know this sounds simplistic, but there are a lot of examples of people continuing their dive AFTER a failure of something that on the surface they would classify as LIFE SUPPORT. You too may have heard about divers who shared a computer because theirs failed to fire up when they jumped into the water; or divers who continued their swim around a reef or wreck breathing from their buddy’s double cylinders because they had used up all the air in their single 80.

The right time to call a dive is also when things start to look or feel different to the plan; or when your buddy starts to deviate from the plan.

The right time to call a dive is BEFORE things get so complicated that you start to lose sight of the simple fact that diving is supposed to be FUN.

You may agree that the Cave Diver’s Credo translates equally well, whether divers are carrying more gear than a Himalayan Sherpa or the bare minimum single tank and stab jacket, and regardless of whether they are back in the engine-room of a deep wreck breathing trimix via the most sophisticated and up-to-the-minute computer-controlled rebreather or cleaning the bottom of their neighbor’s pool using air delivered to them by a lovingly restored vintage twin-hose regulator. If something does not feel fun, never, never hesitate to put up your thumb and let your buddy know: “It’s Miller Time baby; and we are outta here”!
Steve Lewis is SDI/TDI Director of Communications, a published author and accomplished Diver / Trainer. Take Steve’s lead and continue to hone your skills with the training of your choice! Visit to plan your next training adventure.
Here you will find your preferred programs from SDI recreational training to TDI Tech Training or ERDI Public Safety


Announcing the Air Diluent Level 1 Course for rEvo CCR

On the heels of receiving CE approval for the rEvo III CCR the TDI Training Team is pleased to announce the roll out of an Air Diluent Level 1 Course.

Originating from a Russian IDA- 71 apparatus, Paul Raymaekers and his Team undertook the unit through a radical transformation only to find it had not met their needs or expectations. That launched the Belgian based manufacturer in a whole new direction scrapping the transformed IDA-71, leaving behind its limitations but moving forward with a whole new set of knowledge. With a total of five system configurations under two models, the rEvo II and the rEvo III, they have one “just right for your adventure at hand,” no matter where your exploration may take you. Take a closer look by visiting

Since its inception, the rEvo CCR have been a point of discussion with many CCR Trainers. That led Brian Carney, President of TDI to say, “There is no doubt of the growing popularity of the rEvo CCR. Over the last couple of years our members have repeatedly requested TD to launch a program, and I am happy to say we have gladly done it and we look forward to working together with Paul and his TEAM at rEvo-Rebreathers”.

Cutting edge technology and cutting edge Training runs well together. We can only imagine how many other new opportunities this will become the launching pad for!

To learn more about TDI and its offerings, please visit for additional information. Contact the TDI Training department by e-mailing or calling 207-729-420.

Get yourself ready, qualified and certified to take advantage of this and many other growing Technical opportunities with TDI!

Sidemount…It’s Not Just for Cavedivers Anymore!

Sidemount diving has been a staple of the cave diver’s toolkit for a generation, but these days, more and more non-cavers are wearing their bottles at their sides.


There are probably a handful of things happening in the dive industry that we could peg as the latest and greatest idea or innovation. I’d add developments in lighting technology, dive computers, and thermal protection to my list, but surely the hottest trend right now has to be sidemount diving (wearing a totally independent cylinder and regulator system slung on each side of the diver’s body).

Any technical diver old enough to remember “Friends” as a new television series may also remember when sidemount was a very specialized technique with a small and almost cliquish fellowship restricted to England’s Mendip Hills and North Florida’s Karst Country. Finding sidemount training and uncovering a mentor to help you progress in the technique was a lot like joining a mediaeval secret guild; you had to know someone, or have a solid recommendation from an existing initiate; and those outside the circle suspected witchcraft.

In the early days, gear was centered on mostly hand-sewn adaptations of the classic open water stab-jacket style BCD, a few welded bolt-snaps, and lots of bungee cord. The application was ALL about exploring small silt passages; what a good friend of mine describes as “a mighty tight squeeze.”

But that was then and this is now. Times and attitudes have changed. After all, back when NBC first aired “Friends,” the largest sport diving agency had branded TDI’s popular nitrox courses as too complex for the average diver while decompression diving was totally verboten. Now of course, nitrox is the usual choice for most divers regardless of which flavor C-Card they earned as an open-water diver. Most weekend charter rosters include at least a couple of divers planning staged deco; and often a full boatload of weekend warriors all planning for a deep, long dive.

These days, it seems that sidemount really has come out of the closet. To begin with, gone are the hand-wrought BCs. Mainstream manufacturers such as Dive Rite, Oxycheq, Armadillo, Hollis and OMS are producing beautifully crafted harness, butt-plate, wing combinations specifically for sidemount diving. Cam bands – used to convert regular tanks to sidemount tanks in an instant are in several manufacturer’s catalogs. And plenty of stores sell “regulator conversion kits” – an assortment of custom-sized hoses and 90-degree fittings designed to help make the transition from traditional backmounted doubles to sidemount a one-step process. Perhaps best of all, sidemount instruction is readily available and several agencies –SDI and TDI among them – offer specialty ratings and sidemount options for their existing curriculum. This is available to all skill levels in addition to the more traditional cavern and cave.

The real kicker perhaps is that sidemount divers are beginning to pop up on dive boats and at open-water sites, proving that the equipment isn’t just for cave divers anymore. On a brilliant Saturday morning at a popular quarry in Ohio this past summer, I noticed a handful of “tech divers” wearing sidemount kits. On local charter boats too, sidemount divers are starting to make a showing, especially among divers who are trained to execute wreck penetration.

Lamar Hires, head of Dive Rite and one of the early promoters of sidemount diving, files the reasons for using sidemount into two main categories – Lifestyle and Mission Specific. Let’s use Lamar’s definitions as a starting point to explore the overall features and benefits of SM diving.

The ubiquitous North Florida Cave Diver’s Rig consisting of a backplate, simple harness, wing and manifolded doubles, began to establish itself as the gold standard for technical divers sometime in the early 1990s. By the time TDI opened its doors in 1994, this kit configuration, with long hose on the right post, backup regulator and SPG on the left, and a generally minimalist approach to gear selection was what technical divers wore almost universally. But its one-size-fits-all approach and promotion as the universal solution to all dive applications has lost some of its luster over the years and technical divers have looked at other options with an open mind.

With a sidemount configuration, the tanks are carried independently of each other and can be attached to the diver in the water or close to the water. This makes pre- and post dive prep easier on the diver’s back and knees, since the stain of one tank is about half of the stain of two. A good buddy of mine swears that diving sidemount has helped her enjoy dive trips more and use aspirin less!

“There’s no way to describe how good it feels to take all my tanks off in the water, attach them to an equipment line and then walk up that boat ladder wearing nothing heavier than my harness and drysuit,” she says.

Also, the sidemount diver’s gas supply is fully redundant and carried in completely separate systems each with a first and second stage plus an spg (and usually a LP hose). This offers similar gas management options as a set of doubles (some argue more options than doubles) but the valves and first stages are within full sight at the diver’s side rather than behind her back. This obviously makes options during either simulated or real situation shutdowns very simple! There is never any guessing which first stage is giving the diver grief… real or otherwise. This alone has many SM divers-including myself- arguing that there is a safer option in the case of a free-flowing second stage, runaway wing inflator, runaway drysuit inflator or other gas leak

The final “lifestyle” benefit has to do with the ease sidemount diving when traveling. Number one: An SM harness doesn’t have a heavy backplate, keeping luggage within airline baggage allowance. Number two: renting “bottles” at one’s destination is easy! Standard scuba cylinders can be ready for service as sidemount primary tanks quickly, with minimum fuss, and very little extra gear. The addition of a couple of cam straps to the traveler’s luggage makes conversion of almost any sized scuba cylinder the work of a few minutes, making standard stage bottle kits very workable in a pinch.


Going back to the genesis of sidemount diving, we arrive at the original reason to move one’s primary cylinders from one’s back to one’s side: low ceilings and flat bedding planes. While this reality has informed the decision making of cave divers for more than a generation, more and more wreck divers feel that sidemount offers real advantages inside a wreck.

The interior of most wrecks, even those intentionally sunk and cleaned out ahead of time, present special challenges because of the likelihood of entanglement with overhead cables and other debris. A staple of the traditional Advanced Wreck class is a great session to take advantage of. The diver learns the best techniques to free oneself or a buddy from the clutches of a couple of metres of electrical wire and rotting wood typically found in various doubles. Not to say that entanglement in this sort of situation is a non-issue in sidemount, but the number of potential line-traps behind the diver’s head is significantly reduced when he is wearing sidemount kit.

I also find the inherent lateral stability against the effect of roll while wearing a sidemount setup is a huge benefit when scootering; but perhaps that’s a story for another day.

All this said, it is important to remember that no single kit configuration is right for ALL applications. Sidemount is not the silver bullet and is certainly not the best option always and everywhere. However, a growing number of tech and sport divers are finding SM an interesting and enjoyable way to dive in many different environments.

If you’re curious about Sidemount diving, find a workshop-it’s a great way to learn about the best ways to route hoses, hang lights, and configure deco bottles. Having a very flexible alternative to the traditional tech diver’s kit for many divers is worth the extra effort.

Take advantage of the NEW Sidemount program offered by SDI & TDI, visit /index.php?site=2&did=129 to get started today!

Photo Credit: Diverite


Are Your Cylinders Ready for the Season?

It is finally here, that long awaited time period for many of us that we have endured with great anticipation! FINALLY….we are getting back into the water! You have done some reading, maybe even reviewed some notes in your log planning to finish some personal objectives at some favorite sites this year.

You have checked and double checked your rig…but are your cylinders ready?

Here is a simple to follow, yet thorough check list to apply and save as a future reference!

Cylinder Preparation Check List

  • Start with primary cylinders and include manifold doubles and sidemount cylinders
    • Are they O2 cleaned for the year?
    • When is hydro due and should they be: hydrod, O2 cleaned and VIP at one time to save money?
    • Are all the valves turning easy, especially the isolation valve (for manifold doubles)?
    • Are the bands on your doubles tight and free of rust?
    • Are they labeled properly and are the labels still easy to read?
      • Custom mix
      • Nitrox
    • For DIN vales with yoke adapters, remove insert and inspect O-Ring
  • How does the mounting hardware look on your stage or sidemount cylinders?
    • Are the clips moving freely and closing properly?
    • Is the mounting hardware and lines in good shape and not chafed?
    • Are they O2 cleaned for the year?
    • When is hydro due and should they be: hydrod, O2 cleaned and VIP at one time to save money (  Reminder, don’t forget the same applies to your stage bottles)
    • For stage bottles, are they labeled properly and are the labels still easy to read?
      • Oxygen
      • Percentage of oxygen
    • For DIN vales with yoke adapters, remove insert and inspect O-Ring
  • Finally drysuit inflation system
    • Is the VIP and hydro in date
    • Is the mounting hardware still in good working order
    • If using argon, is the “none breathing gas” label still obvious and readable?


Your local TDI facility is standing by to assist you with all of your Tech needs, so don’t put it off any longer! Get your cylinders ready and go make a splash! Visit to find the facility near you!

SDI vs TDI Nitrox: Which One and Why

We are often asked why we have two nitrox programs, one under SDI and one under TDI, and why should someone choose to teach one course over the other…. or even consider both?