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.






Teaching Tips: Personal Dive Computers

By Steve Lewis

We get a considerably varied and pretty constant stream of email into our office from divers across North American and from around the world. Sometimes it’s to tell us how pleased they are about the service they got from one of you folks. Sometimes it’s to ask about the quality of diving in some far-flung corner of the Pacific. Occasionally it’s a complaint. But from time-to-time we get asked to explain why we do things the way we do, and these are usually the most fun to answer!

Last week, I got a message from off one of the many scuba-related forums on the web that we monitor. Apparently this diver’s girlfriend had signed up for an open water course and he was shocked to learn that his local dive store had switched affiliations and was now promoting, what his old instructor termed, “SDI’s superior program!”

That happens more and more these days… but he asked what the differences were between the Open Water program he had taken through another sport diving agency and SDI’s. He explained that he was shocked to learn from his girlfriend that SDI promotes the use of personal dive computers (PDCs) rather than making students work through calculations using tables.

During one of our conversations, he said he felt she was being short-changed and that not learning tables was dangerous. He actually said “if sport divers or occasional divers can’t familiarize themselves with the tables then should such an unsafe person be diving?” Frankly, I was a little floored because it seemed to me he was telling me that ALL SDI-trained divers are unsafe, because their instructors have not made them slog through an antiquated system that most divers forget how to do unless reminded on a regular basis.

For the record, let me share with you want I explained to him because you too may run into someone who harbors similar misconceptions, and although I am sure you have your own version of things, the explanation that follows may help you sometime in the future.

Let’s start at the beginning. SDI is different to the other major sport diving agencies because it was created by people who ran a technical diving agency; the biggest technical diving agency in the world, TDI. The men and women who helped put together its curriculum and developed its courses had the strongest background possible in diver education and diver safety, and the attendee list of those early brain-storming sessions read like a who’s who of recreational diving… both technical and sport branches.

Their primary concern was to create an open water course that made diving an adventure rather than a chore, and one that had a sort of “sky’s the limit” perspective on diver education… after all, many of those early SDI instructors had experience exploring exciting spots around the globe that few divers had ever seen. The majority of them had been teaching people to dive in caves, and running diver programs to depths about three-times the “normal” sport diving limits. So their perspective on how far a student could progress was a mite broader than instructors from other backgrounds!

Right from the beginning, SDI brass determined that all SDI-level divers wear a personal dive computer. In the simplest terms, this determination was driven by safety, and not as my correspondent suggested collusion with the dive computer manufacturers! Personal dive computers have evolved immensely since the first brick-sized units available in the 1980s. They have become easy to read, understand and use. Their functions go way beyond those offered by their predecessors… for example, downloadable graphic dive profiles, and logbook functions. And, most importantly, they are the best tool currently available for controlling ascent speed… something we believe needs to be managed because of what seems to be a very strong association with bubble troubles.

Of course the core function of a PDC is to track average nitrogen loading in real-time and give a good approximation of the decompression status of the person wearing it minute by minute (actually, second by second in many cases). Because of this, among other benefits, a savvy diver is able to maximize her bottom time while keeping within the No Decompression Limits of her dive. No table can come close to this level of accuracy and, by inference, offer comparable security. The mitigation of DCS is never zero regardless of what method is used – tables, PDC or some other Voodoo – but for sport divers, a PDC is without comparison.  In short, a PDC is an extremely useful tool within the budget of the majority of sport divers.

Of course the one important proviso is that when a SDI diver graduates his or her open water class, their instructor has helped them to understand the computer’s functions and benefits, and they have been encouraged to read the user’s handbook and discuss anything they did not immediately understand.

Now on the topic of tables. We do not discourage instructors from teaching tables, in fact all our leadership courses (DM, AI, OWI, SIT, IT) have components where the US Navy, DCIEM and Buhlmann tables are used, but extensive research has told us that sport divers and tables do not mix well. In fact, there are strong indications that unfamiliarity with dive tables among occasional divers keeps people away from diving. Because of this and other concerns about table use on multiple dives, CNS tracking and related issues that may have a negative effect on a diver’s well-being, we discourage tables as primary information.

The arguments for tables actually remind me of the arguments that are offered against technological advances in all forms of sport and pastimes, not just diving. I’ve heard people rally against seat belts and anti-lock brakes, airbags and traction control in cars. (Actually, members of my father’s generation despised synchromesh gears!) But of course these innovations are now standard in any late model car. They save lives!

The vast majority of ski hills don’t allow skiers on their slopes without modern bindings and boots. Leather and duct tape are no goes.

The list goes on and in our industry, there are many of you who may remember the cries against SPGs, BCDs and things that we take for granted now. The old way is NOT the best way, and thinking that tables are somehow superior for sport divers is simply nonsense.

Forgive the personal note but my wife, a smart woman in all but her choice of life companion, was terrified of tables when she first learned to dive. It was not the math or the process that scared her, she’s an executive with one of the largest hotel chains in the world and deals with numbers and process-driven protocols every day. What scared her was getting it wrong. She felt the penalty for a mistake using tables was so severe, she was reluctant to dive. A computer solved that problem… now if I can just get her to master the reverse frog kick…

How does the Online Divemaster Benefit Me?


Information about the newest educational innovation from SDI™, TDI™

1.    Q: I’m sold on the benefits of SDI™ online training for open water and specialties like nitrox, wreck, deep, navigation and so on, but why Divemaster?


A: Often, the instructor who is best suited to develop dive leaders is the one person who has the least time available. The perfect solution is blended learning through SDI’s online training. The proven online system moves your divemaster candidates through their academics freeing up valuable instructor time to work hands-on with them to refine their leadership qualities as well as diving, risk-management, and dive business skills.


2.    Q: Do all my DM candidates have to do all the academics online now?


A: No, you can still teach a DM course the way you have always done with traditional classroom.  However, we believe you will find that your candidates come to class much more prepared if they do the program online first.


3.    Q: How do I get my dive center signed up for this program?


A: Simply contact either your local Regional Manager, or HQ and both can assist in setting up your facility to do the program.


4.    Q: If am already using the online program to do Open Water or Specialties is my facility already set up?


A: Yes and no.  Yes your facility is listed in the new website as an active online facility, but no you have to use a different link for this course.  www.sdi-onlinetraining.comleadership

5.    Q: If I have a link off of my own website to the online program for my own students, do I have to create another link to give access to my students for the DM program?


A: Yes, you can get the unique link using your username and password as a login in on  www.sdi-onlinetraining.comleadership


6.    Q: If a student signs up on the website and pays with a credit card directly on the site, what is the amount my facility gets?

A: The facility is issued a $225 credit and HQ takes care of shipping all the materials they need directly to the dive facility, including a DM manual, Knowledge Quest, and other items.


7.    Q: Can I buy access codes at a discounted rate as I do for the other online courses?


A: Yes, the amount of the discount depends on the facility current buying level.

8.    Q: Are all DM candidates required to choose a dive center to be affiliated with when signing up? 

A: Yes, all SDI courses must be taught through a recognized dive center. 


9.    Q: If I purchase codes for a DM candidate, is my dive center automatically chosen and locked in as the facility as it is with the other online courses?

A: Yes, DM candidates that sign up using an access code you provide to them or via your websites unique link are locked in as your students and you are given the credit.


10.    Q: Is there a user manual for facilities to understand better how the system works?


A: Yes, you can download one off of the members section of the website or contact your regional manager or HQ.


Contact your local SDI, TDI representative or call Cris Merz at 888.778.9073 for more information. Cris can also be contacted via email


Deconstructing the Process of Learning and Instruction

It’s fair to say that the goal of most candidates who are working through an SDI or TDI leadership system to earn their instructor rating is to deliver the best possible standard of diver education possible.


The candidates who perform well, do so in part because they come into their IDC or IT program prepped and ready to learn. They arrive having worked on their diving and in-water skills… laps in the pool, mask clearing, gear removal on the surface… you know the drill.


Some arrive with a few miles logged making presentations… as an AI working with actual students or in front of their family and friends… or the mirror. Regardless of the methodology, they make an impression with their trainers because they’ve worked at to gain some experience, and it’s had a positive impact.


And the serious ones come primed for the knowledge review having studied their textbooks and leadership manual to brush up on dive theory –Gas Laws, signs and symptoms of DCS, etc.


But for the vast majority of newly minted instructors there is something standing in the way of them reaching their goal. What’s missing is the ability to read if effective learning is taking place in their classrooms. For lay educators not armed with the tools supplied by a post grad degree in education, or bloodied by the experience of teaching scuba in the real world with real people for a season of two… or three, this is a tough skill to acquire.


As experienced instructors and instructor-trainers, store owners, bosses, we mentor our new instructors but it’s hard to condense years of responding effectively to signs and signals from students into a few words. But there is help.


Gagne and the eight phases of learning


There are several established educational models in use by professional educators such as teachers, textbook writers, computer programmers, et al to develop instructional materials or presentations. We can learn a great deal from “borrowing” those concepts to help make the classes we lead more effective.


The work of American educator Robert Gagné especially had a profound influence on American education and on military, institutional and industrial training. His model is simple and applicable for scuba instruction.


Gagne explained that for effective learning to take place, whether the instruction is taking place in a classroom, on a factory floor or in a swimming pool, the learner must go through all eight of the phases in his model.


He stated that if one phase is ignored or if there’s a partial breakdown that extends over several phases, learning does not take place. It’s therefore primarily important that each of these phrases occurs, and if there is an issue, some person or material must make up the short-coming or effective learning will not occur.


The following paragraphs briefly describe each of the phases of learning presented by Gagne’s model:


Attention. Attention is the phase that pushes information into the student’s working memory and helps to keep it active there. And so for effective learning, the student must focus full intention on the learning activity itself. Although this is listed as the “first phase,” attention is critical throughout the whole learning process.


Expectancy. During this phase, the student realizes that the end result of learning is going to be something desirable. This develops motivation to engage in the subsequent phases of the learning process.


Retrieval of Relevant Information to Working Memory. This phase is entirely dependent on the student and his past learning experiences. During this phase, the student retrieves from long-term memory the structures that will be helpful in learning new information to him.


Selective Perception. This phase describes the student focusing their efforts on the  essential features of the instructional presentation. One important role of an instructor in this phase is helping students to direct their attention appropriately.


Encoding: Entry of Information into Long-Term Storage. During this phase the student remembers information. The information is transferred into long-term memory by relating the new  information to things that are already stored there.



Responding. During this phase the student uses what has been taught. He retrieves and actively uses the information that has been stored in long-term memory, and demonstrates through an active performance that the learning has taken place.


Feedback. During this phase the student determines the degree to which the performance during the previous phase was satisfactory. Positive feedback on a good performance usually serves as a positive reinforcement.


Cueing Retrieval. During this phase the learner practices recalling or applying the information after it has been initially learned in order to enhance retention of the information or to transfer the learning beyond its original context to a new application.



When Gagne stated that a student must go through all eight of these phases in order for effective learning to occur, he did not state that the instructor is the person responsible for causing all eight of them to occur. What he said was that Somebody (usually either the instructor or the student) must see to it that all of these phases occur, but the actual role of the instructor will vary from situation to situation and from student to student.


For example, during phase one an instructor will introduce a topic to be learned in a way that catches the student’s attention and causes them to develop expectancy (phase two) that it would be interesting to know more about the topic.



The Nine Events of Instruction


Based on the eight phases of learning Gagne developed with others nine events of instruction: useful information for us in the context of improving the effectiveness of the training we deliver and the way we coach new instructors. These focus on activities that can be performed by an instructor or by the instruction system itself to promote effective learning. Here is the list.

Gaining attention: Giving a stimulus to ensure reception of coming instruction

Informing the learner of the objective: Telling student what they will be able to do following successful instruction

Stimulating recall of prior learning: Asking for recall of existing relevant knowledge

Presenting the stimulus: Displaying the content and discussing it

Providing learner guidance: Supplying organization and relevance to enhance understanding 

Eliciting performance: Asking learners to respond, demonstrating learning

Providing Feedback: Giving immediate feedback on learner’s performance.

Assessing performance: Providing feedback to learners’ more performance for reinforcement

Enhancing retention and transfer: Providing diverse practice to generalize the capability 


There is something to be gained in sharing this work with new instructors, and reviewing it in comparison with our current classroom/training techniques. In fact we can use the table below to gain a better understanding of how the events of instruction interlink with the phases of learning. Reading Gagne will never replace the benefits of classroom experience, but it may help to optimize it.


Event of Instruction

Learning Phase

How Teacher or Text Does It

How Students Self-Instruct

When to Skip This Event


Gaining attention




Sudden stimulus change.

Call for attention.





Attentional set

Mood management.

When attention can be assumed – when learner is already alert.


Informing the learner of the objective: activating motivation.



State objectives and relate them to students’ needs and interests.

Student selects own objectives. (This usually comes first.)

Almost never – but maybe if the objective is obvious.


Stimulating recall of prior knowledge.


Retrieval to Working Memory of prerequisite information


Give an exercise or review activity to recall previous information.

Student looks for and retrieves relevant prior information.

Often students do this without even realizing that it is happening.

Almost never – but skillful self-learners may do this themselves.



Presenting the stimulus material.



Selective Perception

Text, audiovisual, or voice presentation.

Objects or demonstration materials

Show distinctive features and focus attention on them.

Student seeks out and finds relevant material to provide instruction.

Almost never – although learners may acquire stimulus material on their own initiative.


Providing learning guidance


Encoding: Entry to Long-term Memory Storage

Provide meaningful context.

Offer organizing strategies.

Relate encoding to the objectives.

Student uses rehearsal or chunking strategies.

Student selects storage structures to retain in-formation.

Student employs cognitive strategies

When the learner already possesses effective cognitive strategies.


Eliciting performance




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?