TDI and Rebreathers: What’s Available?

Feed your curiosity and increase your knowledge base

RebreathersFor anyone that has attend a local dive show, read any diving news or has just spent some time surfing the internet, they have seen that rebreathers, and particularly Closed Circuit Rebreathers (CCR), are all the buzz. Technical Diving International (TDI) heard that buzz in 1995 with the Semi-Closed Circuit Rebreather (SCR) and then again in 2001 with the CCR. Since 1995 a lot of rebreathers have been added to the approved list for TDI training – so many, in fact, that we thought it was time for a review.

Before we get into that review, though, we thought it might be helpful for you to understand why some rebreathers are not on our list. This is by no means a negative reflection on any rebreather manufacturer. TDI selects rebreathers based on the following criteria: annual production of units, user manual and third party testing. That is just a short list of some of the key areas that are evaluated. We have also never authorized the training on “modifie” or “home-built” units. Why? For two of the reasons just listed: there would be no user manual to explain how the unit would work with the modifications or as a home build, and there would be no third party testing. The end goal in everything we do – including approving education on rebreathers – is diver safety.

The first SCR in TDI’s course list was the Draeger Atlantis. The first CCR unit TDI ever approved was the Inspiration Classic; for you old timers that should bring back some memories! These RBs, in hindsight, were pretty straight forward and, of course, not nearly as sophisticated as today’s units. The Atlantis when first released did not even have a PO2 monitoring device; everything relied on a pre-dive checklist that had to be followed. This was also the case with the original Inspiration; however, it did have two (primary and back-up) monitoring devices for PO2.

TDI now has 11 CCR rebreathers on our list. We have come a long way since 2001:

  • Inspiration,
  • Poseidon MK VI Discovery,
  • Evolution,
  • KISS (Classic and Sport),
  • Optima,
  • Megalodon,
  • Titan,
  • Ourboros,
  • Sentinel,
  • Pelegian and
  • rEvo.

Each of these units has their own unique features and applications, and just like open circuit (OC) equipment, each competes to appeal to your personal preferences. For the first time in many years, we have also added a new SCR, the KISS GEM, along with three other SCRs. SCRs certainly have their place in our industry and a market that enjoys their use and simplicity.

We are also very proud to announce that we will be adding two more units to our list: the PRISM II and the Explorer (an active SCR). The PRISM II is an updated model of the PRISM TOPAZ and is now being built and distributed by American Underwater Products (AUP).

So where does all this leave you, the diving professional wanting to step into the world of rebreathers? It leaves you in a position with a lot of good choices but ones that need to be researched… which means you get to do some diving! Most, if not all, of these manufacturers put on events that allow you to try the rebreathers, or you could contact a local TDI rebreather instructor and see if they are putting on a try dive for the SCR or CCR that they are certified to teach on.

Where does this leave the already certified TDI SCR or CCR instructor? You are also in a very good place. Lots of marketing effort is being put into the new products to create brand awareness which means that customers are hearing about them. Your job is to partner with and capitalize on those marketing efforts by the manufacturers and start to capture those customer leads.

TDI will continue to stay on the leading edge of the rebreather training market, and as we do we will send out releases of approved units. We will also add them to our unit specific standards so you can find the list in the member section of our website.

To learn more about the benefits that rebreather training will bring to you and your facility contact your Regional Manager in the US or internationally – visit for the Regional Office serving you.

Once you run deep and you run silent, it will be difficult to turn back!

More With Less!


Now there is a question that can conjure up a myriad of emotions!
What if we told you we are talking about MORE PROFITS?
Here you are at the beginning of yet another year, winter surrounds you (if you are one of our many members in North America) and you are thinking to yourself: “How am I going to do a better job at managing my business and making more money this year?”
Here is a quick read intended to generate some thought and to get you started towards increased profitability.
Look around your business, how many brands do you support? Pick any category, how many Dive suits? Gear bags? Ask yourself: “Can I do more with less?”  And: “Why would I want to?
  • 1.    Fewer vendors means easier to hit higher buying levels, therefore more gross profit.
  • 2.    You and your business become more important to the brands you do support.
  • 3.    FFA is now more obtainable
  • 4.    Less paperwork to process, easier faster receiving, faster bill pay, less bookkeeping
  • 5.    Narrower selection means greater depth, helps avoid “out of stock” situations.
  • 6.    Helps avoid extra charges for “expedited freight” to remedy stock shortages.
  • 7.    Permits greater focus to “specialized equipment” that fits your geographic region and your training philosophy.
Think it through thoroughly and do not react emotionally, as the saying goes “sleep on it”. Before you make a major adjustment to your business, inventory or approaches discuss it with fellow staff, key customers. Time is on your side because if you choose to take this course of action it will take some time to “profitably” make inventory adjustments. After all this IS NOT the market to “blow out inventory” it is crucial you maximize your cash flow and yes your gross profit from each and every sale.
Want to test the concept out of doing more with less? Start with your diver training. You already have access to one of our three Agencies, Scuba Diving International™, Technical Diving International™ and Emergency Response Diving International™ ask yourself the question “Am I maximizing my opportunity, am I taking advantage of teaching all the classes I and my fellow staff qualify for? Am I meeting market demand for instruction?”
If you have any doubt that you are not getting the most from the training you offer reach out and contact us. Let us share with you what other successful facilities are doing with their training! Here is a hint…what are you doing with Intro to Tech? How about Solo Diver? As we undertake the most aggressive travel schedule ever doing more consumer shows then ever we are quickly learning that when we offer these seminars to the general diving public the room is filling up with interested divers!
Why not offer an Intro to Tech or a Solo Diver presentation in your store? You’ll find that the Q&A that follows will scream of opportunity!
Yes you can do more with less! Just look around and figure out to do more with what you have! Be they brands, agencies and most important of all …your customers!
Contact your Regional manager today or reach out to Cris Merz at and let us help you get the most out of the training you offer!


CCR Bailout Philosophy for Cave Diving


By Lamar Hires, co-founder/CEO Dive Rite

There are minimum standards for CCR bailout set by training agencies, and there is the comfort zone. I think people confuse the two.  Training should teach you to evaluate the risk and draw conclusions based on your personal physical ability and personal perception of risk. Sometimes I think divers take the easy way of doing the math. There are many variables for determining bailout needs and reality is never as simple as classroom practice. The experienced cave diver can rationalize anything and practice it to get a memorized response based on repetition. What he can’t control is his breathing rate or the catalyst that triggers the bailout procedure.

To truly determine bailout needs one should consider the circumstances and the factors which lead up to getting off the loop and going to bailout. I understand this from experimenting and building a rebreather.  You never truly know how you will respond when you take your last breath or can’t take one at all. This is sure to elevate your breathing rate and response to the problem.

All this leads to the question “how much bailout is enough?”  The open circuit cave community believes that CCR cave divers don’t take enough bailout because they cannot relate. I try to relate closed circuit needs to open circuit disciplines learned from years of cave diving. I guess after years of starting a dive with about 270 cubic feet of compressed gas I can’t get past the need to have at least 80 cubic feet of bailout gas.  Even if practice gets you out on 30 cubic feet of gas, having at least 80 cubic feet gives you the extra gas to deal with the catalyst that got you off the loop. I think this is the one point training cannot emulate. During training you always know it’s a drill. You wait for the queue and respond. There aren’t any flashing lights or taste of a caustic cocktail. In the real world there are no “abort the drill” signals.

One can argue minimum bailout needs and justify it. On expeditions, bailout needs for closed circuit are rationalized just like the open circuit one-third rule.  Anyone can rationalize their needs verses what’s available. I see it all the time. A dive at home utilizes oxygen for decompression, but on expedition oxygen is not available. Away from a well-equipped fill station  it is ok to do a deep dive on air because it’s a remote area.  I am more concerned about what people rationalize when they have all the resources needed available.

Now the cave diver comes out in me. Redundancy is the key to safety and returning home. For cave diving closed circuit bailout needs should be treated like sidemount, two cylinders for balance, safety and buddy team.  Closed circuit minimum bailout should start with 80 cubic feet just like open circuit and this should be two aluminum 40 cubic feet cylinders for redundancy.  Two cylinders provide multiple advantages:

1)       If you have to go off the loop two cylinders provide the peace of mind that you still have full cave redundancy for the exit. Worn sidemount, these bottles tuck in under the arms for streamlining.  A friend of mine wore a single 80 bailout on a dive and at 3000-foot penetration, 25 minutes away from the entrance his electronics signaled he needed to get off the loop. The diver turned on the bailout bottle to have a HP hose blow. Now he is faced with the dilemma of going back on the loop with indicated failures or to breathe his bailout in single breaths by opening and closing the valve. Not much of a choice. He was able to get back on the loop, but had a major scare.

2)      It is much easier to go from two small cylinders for shallow dives to two large cylinders for deeper dives.  No extra rigging is needed when making this transition so the transition is much easier.

3)      The buddy element is the biggest argument: that is whether to be self-sufficient systems verses the buddy system. I don’t like the idea of single bottle sharing for bailout. I personally will not give up my only full bailout bottle in exchange for a half empty bottle (yes, now the glass is half empty) in hopes that the diver in stress, (yes, he is in stress since he had to get off the loop) has only breathed the bottle down 50 percent before passing it off.

There are three bailout configurations for CCR cave divers: buddy system, self-sufficient, and staged.  I find myself using at least two of them on any given dive. I agree every diver should be self-sufficient, but you should always be ready to help your buddy. CCR divers have more options to them for bailout since their dive is determined by scrubber duration and how much time he wishes to spend based on more physical aspects of the dive. How much decompression are you willing to do? Are you dressed to do the decompression and stay hydrated? Gas supply is usually not a consideration, but bailout is.

Since I subscribe to at least 80 cubic feet of gas for bailout let me share with you several dive scenarios that called for different approaches.

1)      Devil’s Ear – 4000 foot penetration at 100 feet in depth. Since my buddy and I were going to explore some of the side passages beyond the 3000 foot restriction called the Henkel , we opted for a single 80 cubic feet stage each and two aluminum 40 cubic feet sidemount bottles.  My buddy dropped his 80 stage at 1500 feet, while I dropped mine at 3000 feet where we dropped our DPVs.  We went on to explore the smaller side passages with 80 cubic feet of bailout apiece configured in two aluminum 40 cubic feet cylinders.  So the bailout plan was buddy combined with staggered, staged bailouts for the swimming portion of the dive in the smaller, remote passages where we went to self sufficient mode with small sidemount cylinders. This allowed us to explore with less drag and maximize our exploration.

2)      Devil’s Ear – 4200 foot penetration at 100 feet in depth. This dive we had the same penetration as above, yet this was a working dive; a body recovery of a solo cave diver at 4200 feet. The passage was small in places and we knew we would be in zero visibility. Even though my team mate and I were together, we were very busy so we opted to go with two aluminum 80’s each so that if either of us had a problem we could deal with our own bailout needs and still complete the task.  Same dive, but different approach due to conditions of the dive.

3)      Rose Sink – 4500 foot exploration at 140 feet in depth. This dive required the use of all three bailout methods. The dive is a multi-level siphon and the flow increases the farther back you get as feeders add to the total water volume and flow. We staged one 80 each. My buddy dropped his bottle at 1300 feet with a richer mix for the final exit leg and I dropped a bottom-mix bottle at 2500 feet. We dropped DPVs at 3000 feet, keeping two aluminum 40s each for self-sufficient bailout, and then continued the final portion of the dive in a low crawl trying to stay ahead of our silt while we picked up the last of the survey on the last 900 feet of passage.

Based on my experience and the lessons learned from hard knocks received over decades of technical diving, one must evaluate every dive mission based on its needs for bailout planning. If you have the opportunity, talk to local divers to see what kind of planning the open circuit divers use for the site to be sure you use the proper bailout for the dive. Look at the mission, and the team, and then plan according to ability, experience and familiarity with the system.  You cannot make every dive fit the same bailout planning unless you use this as a tool to limit your penetration.  Proper planning of bailout is just as important as planning your decompression or mission. Make sure all team members are up to it and do their part in any team effort of staging gas. Practice various methods and see what works for you.

Lamar Hires is an active diver, equipment manufacturer, designer and instructor. He is well-known for his work to improve general diver safety and specifically for the promotion of common-sense protocols to help manage diver safety in overhead environments, closed-circuit rebreathers and Open-Circuit sidemount kit configurations.

The articles, positions and statements contained in this publication are not necessarily those of SD™ TDI™ or ERDI™ its BOD, officers or
employees.  Opinions, conclusions, and other information in this publication are solely those of the authors and are neither given nor endorsed by the agencies mentioned. Total editorial freedom and expression is solely retained and the responsibility of the editors/writers.

The Year of the Rebreather

Poseidon Discovery – now available för 10,000 diving instructors all over the world

TDI™ (Technical Diving International™), the largest technical certification agency in the world, is now offering training in the sports diver Rebreather, also known as Poseidon Discovery. TDI is seen as an innovator always bringing  new, exciting and functional diving techniques and programs to the general diving public.

All of the 10, 000 TDI-certificated diving instructors around the world now have the opportunity to get educated in the Rebreather system. This means that the possibility för scuba divers to be taught by an Rebreather-educated instructor has increased considerably.

“I would call this the crucial step för the Rebreather to reach the great amount of recreational divers all over the world,” says Kurt Sjöblom, CEO of  Poseidon Diving Group AB. “My prediction is is that 2010 will really be the year of the Rebreather!”



The world’s first closed breathing system for recreational divers


Unlike traditional breathing systems for recreational divers, Poseidon Discovery reuses the exhaled breath. This extends the diving time from 40 minutes to several hours. In November 2008, Poseidon Discovery was awarded the international award “Best of What’s New Award” by Popular Science, one of the largest popular science magazines.


For further information, please contact:  

Kurt Sjöblom, CEO, +46706340552,

Mats Lennartson, Press Contact, +46707902468, 



For further information about diver education from TDI, please contact




About Poseidon Diving Systems AB


Poseidon was founded by divers, for divers. When Ingvar Elfström launched the world’s first single hose regulator in 1958 it became an immediate sensation. The company currently has 30 employees and over 2000 agents worldwide. Headquarters and manufacturing is located in Gothenburg, Sweden.