Christian McDonald Is 'Honorary Underwater Instructor'

April 2016, Scripps, Scientific Diving Officer, Christian McDonald, Honorary Underwater Instructor, Los Angeles County Underwater Unit, LA County lifeguards, scientific diving, public safety program, James Stewart, SIO, Dr. Wheeler J. North, Los Angeles, Rosemary E Lunn, Roz Lunn, The Underwater Marketing Company
Christian McDonald received his award on 23rd April 2016

It has just been announced that Scripps Scientific Diving Officer Christian McDonald has been named an honorary Underwater Instructor by the Los Angeles County Underwater Unit.

He received this honour at the program's annual awards dinner on 23rd April 2016 for his contributions supporting their Underwater Instructor Certification Course.

The program is the world's oldest public safety program. It was developed in 1954 by LA County lifeguards participating in the then newly developed SIO scientific diving course. During the 62 year period over 1,100 underwater instructors have been certified.

Christian joins only 7 other persons, including SIO DSO emeritus James Stewart and SIO graduate Dr. Wheeler J. North, as honorary instructors for the county of Los Angeles. Congratulations Christian.

SOURCE: The Scripps Center for Marine Biodiversity and Conservation


Be RoSPA CCR Aware

Rebreather Forum 3, RF3, Rosemary E Lunn, Roz Lunn, Rosemary Lunn, The Underwater Marketing Company, Simon Mitchell, Neal Pollock, Drew Richardson, Karl Shreeves, Mark Caney, Michael Menduno, Richard Pyle, Peter Denoble, DAN, PADI, AAUS, Richard Vann, rebreather safety, ANDI, IANTD, TDI, rebreather, training, diver training, rebreather market,  diving certification, Betts, Carney, Dituri, diver certification numbers, market analysis, diving data, total number of diving certs, international association of technical dives, technical diving international

In 2011 RoSPA (The Royal Society for the Prevention of Accidents) was asked to promote the safe use of rebreathers. To this end RoSPA worked with a number of rebreather industry experts to identify key safety issues.

The result was a film that gives divers and those new to rebreathers a solid awareness of the key safety factors for diving with rebreathers.

Three years ago today - Friday 18th May 2012 - this film was unveiled at a very important international safety symposium called Rebreather Forum 3. In fact 'CCR Aware' opened #RF3.

Today this film is still pertinent and worth a watch for anyone interested in, or who dives a rebreather.

Simon Mitchell Receives DAN / Rolex Award

The 2015 winner of the DAN / Rolex Diver of the Year Award - one of the most prestigious honours in scuba diving - has just been announced by Divers Alert Network. For the last quarter of a century DAN has partnered with Rolex to acknowledge excellence in diving and dive safety. This year the prolific work that Associate Professor Simon J Mitchell has done, has been recognised.

Dr Simon Mitchell, Anaesthesiology, University of Auckland, New Zealand, Rosemary E Lunn, Roz Lunn, The Underwater Marketing Company, DAN Rolex Award, Diver of The Year, Fourth Element, Dr Neal W Pollock, EUROTEK Advanced Diving Conference
Dr Simon Mitchell is an avid tech and rebreather diver Image Credit: Dr Neal W Pollock

This award is given to “an individual who has made significant contributions to dive safety and / or the DAN mission over the past year.” Without a doubt, Simon Mitchell fulfills this criteria.

I first met Dr Mitchell in 2008 when I co-organised the inaugural EUROTEK. During the run up to the event, the late Carl Spencer praised a diving doctor he had heard speak at OZTek. Carl was keen that this hyperbaric expert should also present at our international advanced and technical diving conference. At this time Simon Mitchell’s name was not that well known by northern hemisphere advanced and technical divers.

Simon was only meant to deliver two sessions at EUROTEK.08, a different talk each day, but because another speaker had been unable to attend at the last minute, he willingly stepped into the breach and gave four different talks over two days. I spoke to him on the Sunday night post-conference, and noted he was absolutely exhausted. It was obvious he had given his all, both educating and engaging an audience of European advanced and technical divers. Simon easily fulfills the wording for the DAN / Rolex Diver of the Year Award; “he goes beyond to ensure that all divers prepare smarter through proper dive education…

The diving forums went wild post EUROTEK.08. The northern hemisphere divers loved and appreciated the fact that Simon Mitchell didn’t dumb down decompression theory. Instead he took time to carefully explain quite complex information to them, in a non-patronising manner, communicating it in such a way that everyone in the audience left having learnt something useful.

Simon Mitchell, Decompression Theory, Rebreathers, The ICC, EUROTEK, Rosemary E Lunn, Roz Lunn, Leigh Bishop, Mark Dixon, The Underwater Marketing Company
Simon Mitchell speaking to a packed hall at EUROTEK Image Credit: Jason Brown


Dr Simon Mitchell is a fantastic speaker with a knack of explaining medical information to non medics, yet also keeping the medics engaged.” Mary Sinclair

After attending all of Dr Simon Mitchell’s lectures I feel like I’ve had a crash update in the latest decompression theory.” Sebastian Chander

Simon Mitchell was engaging and funny and has a knack for making complex subjects interesting and easy to understand for the layman.” Howard Payne

Dr Simon Mitchell is a physician with specialist training in anaesthesiology and diving medicine. He is the Head of the Department of Anaesthesiology at the University of Auckland in New Zealand and divides his time between the operating theatre, teaching, research and lecturing around the world. Simon holds a medical degree, Diplomas in Occupational Medicine and Diving Medicine, and a PhD in medicine. He is board certified in anesthesiology and hyperbaric medicine.

The DAN / Rolex Diver of the Year Award is given to “an outstanding individual who has devoted their career to making diving safer for all of us.” Simon Mitchell has authored or co-authored 104 publications including books, text book chapters, scientific journal articles and papers, and workshop proceedings. He sits on three editorial boards (Journal for Extracorporeal Technology, Undersea and Hyperbaric Medicine, and Diving and Hyperbaric Medicine) and is on the Medical Advisory Board for DAN South-east Asia / Pacific and the DAN USA Research Committee.

Since 2008, I have worked with Dr Mitchell on a number of international events. He has spoken at every EUROTEK; 2008, 2010, 2012, 2014 and he is slated again for 2016. He also talks and lectures throughout the world at many medical and diving conferences and events. He says (when asked) that he loves talking to divers because they are an involved hungry curious audience that absorbs information.

Rebreather Forum 3, RF3, AAUS, DAN, PADI, Dr Richard D Vann, Dr Petar J Denoble, Dr Neal W Pollock, Rosemary E Lunn, Roz LunnIn May 2012 Simon Mitchell beautifully accomplished what many of us on the Rebreather Forum 3 organising team thought to be an unenviable and challenging job, and made it look simple. Simon chaired the final two-hour session at Rebreather Forum 3, the purpose of which was to forge an agreement for consensus recommendations of the meeting. (This three-day safety symposium was hosted and driven by the AAUS, DAN and PADI).

Simon successfully got the various communities to ratify consensus on 16 safety points. During the session, Simon actively listened and carefully took into consideration every argument delivered from the floor, amalgamating the relevant issues into acceptable form. As a result many recommendations have already been adopted by the worldwide rebreather community in the hope that they will reduce rebreather accidents and fatalities. Simon Mitchell’s action at RF3 demonstrated beautifully he is “a leader in the dive community.”

Inner Space 2014, Divetech, Georgia Hausserman, prebreath, PADI TecRec, Rosemary E Lunn, Roz Lunn, The Underwater Marketing Company, Nancy Easterbrook, rebreather diving
PADI TecRec Consultant Georgia Hausserman doing a pre-breathe during Divetech's Inner Space Image Credit: Rosemary E Lunn

The DAN / Rolex Diver Award is given to “a diver who actively promotes and supports DAN’s mission and dedication to incident prevention, management and protection.” Evidence of this was confirmed by a paper entitled ‘The five minute prebreathe in evaluating carbon dioxide absorption in a closed-circuit rebreather: a randomized single-blind study’ published in Diving and Hyperbaric Medicine, for which Dr Mitchell was the senior author. He worked with colleagues from various key institutions including Duke University.

This research had been inspired by the rebreather community. This is a ‘hungry for knowledge’ community, and this thirst is partially driven by technology. Equipment continues develop and evolve allowing deeper and / or longer dives to be conducted that just a few years ago we used to consider improbable. At the turn of the century 100 metre / 300 foot technical dives were considered cutting edge. Today these kinds of depths are the norm for many divers. It is of little surprise therefore that extreme divers and explorers are asking quite challenging physiology questions.

In 2014 Simon Mitchell therefore set out to answer a controversial topic - just how effective is the five minute pre-breathe that all rebreather divers undertake prior to entering the water? A minimum pre-breathe period of five minutes is usually prescribed, on the basis this timeframe allows the diver to recognise elevated carbon dioxide levels in the scrubber, ie shortness of breath. Simon, along with Dr Neal W Pollock, devised a research study to confirm whether the five minute prebreathe is an appropriate sensitive test and does reveal CO2 scrubber problems, or whether it is actually a waste of time.

Simon shared this key research with the recreational and technical diving community, presenting it at EUROTEK.2014 and OZTEK.2015.

Simon Mitchell, Pete Mesley, Lust4Rust, Bikini Atoll, Truk Lagoon, AP Diving, Rosemary E Lunn, Roz Lunn, The Underwater Marketing Company
Simon Mitchell about to jump in Bikini Image Credit: Pete Mesley

Simon’s current research interests include the pathophysiology and treatment of decompression illness and, in particular, the pathophysiology of inner ear decompression illness. He is also interested in the incorporation of CO2 monitoring in closed circuit rebreathers, and the use of checklists to improve safety in the operating room and during diving.

Simon not only talks diving, he an avid technical diver. He began diving in 1972 and he is still an active current diver today, usually diving a closed-circuit rebreather. He has completed over 6000 recreational, scientific, military, and occupational dives and regularly uses rebreather technology to facilitate the exploration of shipwrecks and deep reefs. Simon's notable underwater achievements include helping to positively identify the SS Cumberland and working with Pete Mesley to identify and then recover the Port Kembla ships bell. He was also part of a team that helped confirm that the wreck of hospital ship AHS Centaur was mis-identified, and is often the diver medic on extreme remote rebreather and technical diving expeditions to Truk and Bikini Atoll.

DANeLogo11“We are very pleased to name Dr Simon Mitchell as this year’s DAN / Rolex Diver of The Year,” said Bill Ziefle, President and CEO, Divers Alert Network. “Simon’s academic and diving achievements are impressive and his accomplishments stood out amongst a field of worthy nominees. His life-long dedication to diving has made a significant impact on safety and has advanced our great sport."

“I am delighted and honored to receive the DAN / Rolex Diver of the Year Award" stated Simon Mitchell. "Like a number of my colleagues who perform similar roles, I enjoy being immersed in the diving community and need little more than this to motivate me. I am deeply appreciative of the recognition this award brings and I are very excited to attend the Beneath the Sea Show and Awards Banquet. My sincere thanks to DAN, Rolex and the selection committee."

Stephen Frink, Beneath The Sea, Secaucus, New Jersey, Dr Neal W Pollock, Dr Simon J Mitchell, Rosemary E Lunn, Roz Lunn, The Underwater Marketing Company, Jean-Michel Cousteau, DAN Rolex Diver Of The Year Award
Dr Simon Mitchell with Dr Neal Pollock and Rosemary (Roz) Lunn at 2015 Beneath The Sea Gala Dinner Image Credit: Stephen Frink

Dr Simon Mitchell received his award at the 2015 Beneath the Sea Dive Show in Secaucus, New Jersey. He was presented with an Oyster Perpetual Rolex Dive Watch and a commemorative wall plaque. In addition, Rolex donated $15,000 to DAN to support essential safety initiatives such as medical research, safety education and first aid training.

The Underwater Marketing Company's 2014!

Sport Diver Magazine, Mark Evans, Apeks Aqua Lung, Shearwater Research, Suunto Dive Computers, TEKDiveUSA, Randy Thornton, Light Monkey, Tom Mount, Diving Awards, Rebreather Forum 3, RF3, Dr Richard D Vann, Dr Neal W Pollock, Dr Petar J Denoble, Girls on Gas, Rebreather divers, Inner Space, Divetech, Nancy Easterbrook, James Roberton, Poseidon Rebreathers, Steve Newman, Rosemary E Lunn, Roz Lunn, diving Cayman Islands, Scuba Radio, Greg Holt, XRay Mag, X-Ray Magazine, Anglesey ScubaFest, EUROTEK, advanced and technical diving conference, The ICC, Dive Rite, DEMA Show, The Underwater Marketing Company, New Product Showcase

2014 was a fantastic year for The Underwater Marketing Company. Rosemary E Lunn (Roz) regularly contributes to a number of diving publications, including Sport Diver Magazine and X-Ray Magazine. Getting your work printed is always special. But nothing is quite so thrilling as being featured on the front cover.

The first half of the year was taken up consulting on and establishing an inaugural technical diving event in North America; TEKDiveUSA. Roz and the Thorntons were supported and assisted by some amazing and talented Smurfs, and the international team of speakers, sponsors and exhibitors weren't bad either. A favourite memory was being grabbed by gleeful Tom Mount who was chuffed to receive the Lifetime Achievement Award.

From Miami Roz flew straight to Grand Cayman to work Divetech's Inner Space. If every dive centre was as well run as Nancy Easterbook's establishment, the diving industry would be in great shape. This week long event attracts rebreather divers from all over the world for a number of reasons, including the plethora of underwater attractions this tropical island offers. The highlight of Inner Space was being made an ambassador for Poseidon Rebreathers, a fun time machine with the ability to do some serious diving.

The summer saw the publication of the long awaited Rebreather Forum 3 Proceedings. (Click the link to get your free copy of this invaluable resource from this 2012 international safety symposium). Anyone involved with or diving rebreathers ought to read it.We attend a number of scuba shows and events throughout the World. In the USA Roz often bumps into Greg the Divemaster from Scuba Radio. This online radio show has been broadcast for 17 years. It is always good to be able to contribute to this programme.

In August, 200 divers descended on North Wales for The Anglesey ScubaFest. Diving, snorkelling, discover scuba, freediving clinics, kit try dives, bands, beach combing, beverages and bonne amid. £100 was raised for local charities and a good time was had by all.Time for another fab event. In September 500 divers, industry movers and shakers, explorers, experts and specialist exhibitors from all over the globe headed for the ICC in Birmingham. EUROTEK Advanced Diving Conference, the major European advanced and tech diving conference turned 4 this year! Our gorgeous gala awards dinner was even more glittering and we raised £4,000 for the Rubicon Foundation, thanks to the generosity of divers and sponsors alike.

It only seemed days later that it was DEMA Show in Las Vegas. Roz worked with Dive Rite on the launch of their new LX 20 Primary handheld torch. It was great to help produce a sexy display iin the New Products Showcase.So that is glimpse of some of the highlights of 2014 - a year of scuba event management, journalism and PR. Here is to a great 2015!

Rebreather Forum 3 Conference Proceedings Now Available

The RF3 proceedings are now available, online and free to anyone to download!

Rebreather Forum 3 Proceedings, RF3, 2014, Rebreather Forum 3, RF3, Dr Nick Bird, Mark Caney, Dr Petar Denoble, Rosemary E Lunn, Roz Lunn, Christian MacDonald, Dan Orr, Dr Neal W Pollock, Dr Drew Richardson, Karl Shreeves, Dr Richard Vann, AAUS, DAN, PADI, The Underwater Marketing Company, rebreather diving, scuba diving, American Academy of Underwater Sciences
RF3 Proceedings are available for free online

The Rebreather Forum 3 Proceedings have been published in both print and electronic format following the safety symposium held from 18 - 20 May 2012 at the Caribe Royale Hotel in Orlando, Florida. Two years in the planning and two years in the writing, the 324-page rebreather publication showcases state-of-the-art and science of rebreather diving through the experience and knowledge of some of the world’s leading specialists in education, operations, physiology, medicine and safety. This meeting followed the Rebreather Forum 2 conference which was held in 1996.

The goal of Rebreather Forum 3 was to positively impact the safety of recreational, professional, scientific, media and military rebreather divers by sharing latest developments and best practices. Educational sessions took place in seminars that discussed history and evolution, medicine and physiology, business and operations, incidents and their investigation, design and testing, and training and operations. Safety was the key theme and participants were informed about the most common causes of rebreather incidents and fatalities in hopes of reducing their future occurrence. To round out the meeting, participants were able to gain hands-on experience through various pool sessions.

The 11-member, Rebreather Forum organizing committee comprised Dr. Nicholas Bird (DAN), Mark Caney (PADI), Dr. Petar Denoble (DAN), Michael Lang (American Academy of Underwater Sciences), Rosemary E Lunn (The Underwater Marketing Company), Christian MacDonald (American Academy of Underwater Sciences), Dan Orr (DAN), Dr. Neal W Pollock (DAN), Dr. Drew Richardson (PADI), Karl Shreeves (PADI) and Dr. Richard Vann (DAN).

Rebreather Forum 3, RF3, Dr Nick Bird, Mark Caney, Dr Petar Denoble, Rosemary E Lunn, Roz Lunn, Christian MacDonald, Dan Orr, Dr Neal W Pollock, Dr Drew Richardson, Karl Shreeves, Dr Richard Vann, AAUS, DAN, PADI, The Underwater Marketing Company, rebreather diving, scuba diving, American Academy of Underwater Sciences
The Editors of the RF3 Proceedings (from l to r); Dr Neal W Pollock, DAN Research Director | Dr Richard D Vann, Professor Emeritus Duke Anesthesiology | Dr Petar J Denoble, Vice President DAN Research

“We planned this Forum to introduce divers without rebreather experience to the equipment as well as to assist experienced rebreather divers in refining their skills. This was the ideal format to share ideas and listen to some of the world’s most respected experts on rebreather diving," stated Dr. Richard Vann, former Vice President of Research, Divers Alert Network.

Publishing the Rebreather Forum 3 proceedings is a significant accomplishment by the AAUS, DAN and PADI. All three partners are very pleased to share this invaluable resource with the diving community, in order to help make diving safer. It is hoped that the knowledge gained will reduce incidents and fatalities among rebreather divers.

PDF copies of the complete RF3 Proceedings can be downloaded immediately at no-cost from the DAN website. Print copies will be available in the near-future through a print-on-demand service. More detailed information can be found at the Rebreather Forum 3 website;


TEKDiveUSA.2014 Attendees To Receive A PADI Rebreather Checklist

PADI (Professional Association of Diving Instructors) has today confirmed that TEKDiveUSA.2014 attendees will receive a 'Type T' rebreather checklist in their conference bag.

PADI_Rebreather Checklist_RF3_Rebreather Forum 3_Dr Drew Richardson_Christian McDonald_AAUS_DAN_Dr Petar Denoble_Dr Neal W Pollock_Dr Richard D Vann_Rosemary E Lunn_Roz Lunn_The Underwater Marketing Company_TEKDiveUSA_EUROTEK_RF3 Consensus Statements_safety_rebreathers_checklists_Mark Caney_Karl Shreeves_scuba diving
PADI 'Type T' Rebreather / CCR Checklist

Two years ago this month PADI, along with the AAUS and DAN, hosted Rebreather Forum 3. This three day safety symposium was convened to address major issues surrounding rebreather technology, and its application in commercial, media, military, scientific, sport and technical diving. Experts, manufactures, instructor trainers, training agencies and divers from all over the world discussed this technology and shared information.

The programme included dedicated sessions covering topics such as medicine and physiology, closed circuit rebreather (CCR) orientation, business and operations, CCR familiarization, training, design and testing, and incident analysis.

Associate Professor Simon J Mitchell chaired the final session at RF3 and, as a result, 16 key consensus statements were agreed and ratified by the global rebreather community. You can hear this presentation by clicking here.

Two of the 16 consensus statements agreed at Rebreather Forum 3 concerned the use of checklists. RF3 acknowledged the overwhelming evidence demonstrating the efficacy of checklists in preventing errors and two recommendations were made. These are listed below.



The forum acknowledged the overwhelming evidence demonstrating the efficacy of checklists in preventing errors in parallel fields that share similar technical complexity. Two recommendations regarding checklists were consequently agreed:


The forum recommends that rebreather manufacturers produce carefully designed checklists, which may be written and / or electronic, for use in the pre-dive preparation  (unit assembly and immediate pre-dive) and post-dive management of their rebreathers.

– Written checklists should be provided in a weatherproof or waterproof form.

– The current version of these checklists annotated with the most recent revision date should be published on the manufacturer’s website


The forum recommends that training agencies and their instructors embrace the crucial leadership role in fostering a safety culture in which the use of checklists by rebreather divers becomes second nature.




The forum applauds and endorses the release of pooled data describing numbers of rebreather certifications by training agencies, and encourages other agencies to join ANDI, IANTD, and TDI in this initiative


The forum endorses the concept of making minimum rebreather training standards available in the public arena.


The forum endorses the concept of a currency requirement for rebreather instructors. We recommend that training agencies give consideration to currency standards in respect of diving activity, class numbers, and unit specificity for their instructors.


The forum recognizes and endorses the industry and training agency initiative to characterize “recreational” and “technical” streams of sport rebreather diver training. These groups will have different operational, training and equipment needs.




The forum recommends that training agencies provide rebreather divers  with a simple list of instructions that will mitigate common errors in evidence preservation after a serious incident or rebreather fatality.

– These instructions will be developed under the auspices of the Undersea and Hyperbaric Medical Society Diving Committee in consultation with the relevant RF3 presenters.


The forum endorses the concept of a widely notified centralized “on-call” consultation service to help investigators in avoiding errors or omissions in the early stages of a rebreather accident investigation, and to facilitate referral to expert investigative services.


The forum recommends that in investigating a rebreather fatality the principal accident investigator invite the manufacturer of the incident rebreather (or other relevant equipment) to assist with its evaluation (including the crucial task of data download) as early as is practicable.


The forum endorses the DAN worldwide initiative to provide a means of on-line incident reporting with subsequent analysis and publication of incident root causes.




The forum recommends that all rebreathers incorporate data logging systems which record functional parameters relevant to the particular unit and dive data, and which allow download of these data. Diagnostic reconstruction of dives with as many relevant parameters as possible is the goal of this initiative.

– Footnote: An ideal goal would be to incorporate redundancy in data logging systems, and as much as practical, to standardize the data to be collected


The forum endorses the need for third party pre-market testing to establish that rebreathers are fit for purpose. Results of a uniform suite of practically important unmanned testing parameters such as canister duration, and work of breathing (qualified by clear statements of experimental parameters) should be reported publicly. Ideally, this testing should be to an internationally recognized standard.


The forum acknowledges recent survey data indicating a poor understanding of rebreather operational limits in relation to depth and carbon dioxide scrubber duration among trained users, and therefore recommends:

1. that training organizations emphasize these parameters in training courses.

2. that manufacturers display these parameters in places of prominence in device documentation and on websites.


The forum strongly endorses industry initiatives to improve oxygen measurement technologies, and advocates consideration of potentially beneficial emerging strategies such as dynamic validation of cell readings and alternatives to galvanic fuel cells.


The forum identifies as a research question the issue of whether a mouthpiece retaining strap would provide protection of the airway in an unconscious rebreather diver.


The forum identifies as a research question the efficacy of a full face masks for use with sport rebreathers.


Dr. Richard D. Vann to be awarded prestigious NOGI

Dr Richard D Vann_Rebreather Forum 3_RF3_NOGI Award for Science_Rosemary E Lunn_Roz Lunn_The Underwater Marketing Company_flying after diving reserach_Dr Neal W Pollock_diving physiology
Dr. Richard Vann gave a number of safety and physiology talks at the 2013 DEMA Show
Photo Copyright: Rosemary E Lunn / The Underwater Marketing Company

The Academy of Underwater Arts and Sciences has announced that Dr. Richard D. Vann has been selected for induction into the 2014 Academy of Underwater Arts and Sciences (AUAS) Fellow Program.

Dr. Vann’s work and lifetime dedication to dive science earns him a place alongside industry icons.

This coveted award is widely recognised as the oldest and most prestigious in the diving industry. The NOGI has been awarded on an annual basis since 1960 to a select group of divers and undersea visionaries who rank at the top of their fields in arts, science, sports / education, environment, and distinguished service. In 1993 the AUAS was created to administer the NOGI award.

Dr. Vann, Vice President of Research for Divers Alert Network (DAN) (1990-2010), current consultant to DAN and Assistant Professor Emeritus at Duke University Medical Center will be inducted into the AUAS in the Science category and will receive a NOGI Award for his efforts and contributions to the underwater world.

Dr. Vann’s work in diving and environmental physiology spans nearly 50 years with Ocean Systems, Inc., US Navy Underwater Demolition Team-12, Duke Hyperbaric Center and Divers Alert Network. His work includes accomplishments such as the Johnson Space Center’s Group Achievement Award from NASA in 2011, and the Albert R. Behnke Award from the Undersea and Hyperbaric Medical Society. Dr. Vann was awarded this in 2012 for outstanding scientific contributions to undersea biomedical activity. His most recent work was on Rebreather Forum 3. Dr. Vann was one of key drivers behind this safety symposium and he is the lead editor on the subsequent conference proceedings. These are due to be published shortly.

“Receiving a NOGI is exciting and quite an honor,” said Dr. Vann. “Understanding diving safety, particularly fatalities and decompression sickness, has been my major professional interest. I am most pleased by this recognition.”

This NOGI award will be presented to Dr. Vann at the 54th Annual NOGI Awards Gala held during the DEMA Show in November 2014.

“DAN is proud to have one of our own inducted into this elite group of dive industry professionals,” said Bill Ziefle, President and CEO of Divers Alert Network. “Dr. Vann has spent a lifetime advancing dive safety research and it is exciting to see him receive this great honour. His scientific contributions have made a significant impact in our sport.”

Associate Professor Simon J Mitchell stated, “Dr. Vann has devoted much of the latter part of his career to identifying unresolved issues of substantial practical importance to the diving community, and has set about resolving them. Frequently this has involved the exhausting task of organising and orchestrating workshops to weigh evidence and generate consensus. It is unquestionably fair to say that no individual in the diving science community has contributed more time and effort in this regard than Dr. Vann. I believe our community owes this archetypal ‘scholar and gentleman’ a huge debt of gratitude and I am thrilled to see him recognised in this way.”

The Academy Fellowship and the Underwater Society of America are responsible for the nomination and selection of all NOGI Award winners. Each year, AUAS invites Academy fellows to recommend nominees for a prestigious NOGI Award. To recommend future NOGI recipients, simply explore the roster of NOGI Fellows on the AUAS website ( to determine the most appropriate contact person.

Joining Dr. Vann are four other NOGI Awardees: Lad Handelman (Distinguished Service); Richard Ellis (Arts), Bill Macdonald, (Environment), and Mike Hollis, Sports & Education.

Poseidon US Operations move from Texas to California

Poseidon Diving Systems, Inc. have moved from Texas and is now based in Los Angeles, California.

Poseidon Diving Systems, SE7EN rebreather, James Roberton, Tasha Wallace, Peter Swartling, Richard Swartling, Richard Pyle, Bill Stone, Rebreather Forum 3, RF3, Rosemary E Lunn, Roz Lunn, The Underwater Marketing Company, Steve Newman, Paul Toomer, SSI International The company management structure is unaltered. James Roberton remains President with Tasha Wallace as Sales Manager, whilst Todd Martin is the Service Trainer.

Poseidon's new address:
1720 Main Street
Venice, CA 90291

New phone: (310) 821-8800
New fax: (310) 821-7800
Main Email:
Orders Email:

Rebreather Cell Warning Advice by Mike Fowler, Silent Diving

At some point in your CCR diving career you are likely to encounter a cell warning. Besides pressing the right button to make it go quiet, do you really know what to look for or do about it?

Cell warnings are given by AP rebreathers when one cell deviates from the average of the closest two by more than 0.2 bar. It is the machine's way of telling you that all is not well and you need to check it out. It might be just that one cell is reacting slower than its partners or may be something very serious indeed.

The important point is that YOU need to check it. Just assuming the machine will take care of you and suppressing the warning is extremely dangerous. Understanding how the machine works is a valuable tool in your armory. It might seem obvious but it is always worth remembering that when diluent is added to the loop you expect the PO2 to fall, and when oxygen is added you expect the PO2 to rise.

Ambient Pressure Diving, Martin Parker, Silent Diving, Mike Fowler, rebreather cell warnings, Rosemary E Lunn, Roz Lunn, The Underwater Marketing Company, Rebreather Forum 3, RF3, diving safety, Evolution, Vision electronics


With the Vision electronics you can do all sorts of diagnostics that can help you to decide on the correct course of action in the water but also after the dive the download allows you (and the factory or Silent Diving) to diagnose what happened.

A diluent flush is seen as a great method of checking cells and at the same time ensures you have a life supporting gas mixture in the loop, but from observing divers and downloads it is clear that very few do a diluent flush effectively enough to check cells. You must watch the display as you are doing to flush. The problem often arises from the fact that as soon as the PO2 goes below the setpoint the machine adds oxygen, what’s happening is you are trying to lower the PO2 at the same time as the machine is trying to raise it. The simple answer is; change to the low setpoint (by pressing and holding the middle button, regardless of whether you use Manual, Auto or Gradual setpoint change methods) and then do the diluent flush for 5 - 10 secs.

Providing you are using an appropriate diluent for the dive, one that is not too oxygen rich and you do the diluent flush properly, the displayed PO2 should drop very rapidly to the expected value for that diluent at that depth. The expected PO2 is easy enough to calculate if you measure depth in meters, but not quite so straight forward if you measure depth in feet. You just need to go into Menu mode, by pressing the outside two buttons and scrolling through until you get to the PO2 screen where it shows you the expected PO2 at this depth should you flush with diluent or oxygen.

You are looking for the reaction speed of the cells, do they fall at roughly the same speed and do they reach the expected value? If for instance, only cell 1 hits the expected value, then when you change back to the high setpoint that cell is most likely to be the accurate cell at the high setpoint. As oxygen is added watch the cell displays to see if they rise at roughly the same speed and do they get to setpoint?

APD Handset, Ambient Pressure Diving, Silent Diving, Matthew Outram, Rosemary E Lunn, Roz Lunn, The Underwater Marketing Company
Image by Matthew Outram


Cell warnings can occur for a number of reasons, it might be that one cell simply reacts slightly slower to a gas change, but more importantly it could be letting you know that the machine’s voting logic is no longer a valid way to keep you alive.

When this happens don’t blindly continue thinking the same as the machine, believing the closest two are accurate.

A diluent flush may be all that you need to do to get rid of the cell warning but a persistent cell warning is telling you that the voting logic is not going to work, and it’s your job to find out which cells are giving the correct values. Just because the machine thinks the nearest two are correct doesn’t mean they actually are, and then once you find out which cell or cells is / are correct, then you can fly it manually.

Once you start seeing two low cells and one 0.2+ bar higher, it would be prudent to lower the setpoint. This would potentially lower the setpoint below the two current limited cells’ outputs, allowing them to work properly again and if successful, lower the high output cell bringing it within the safe PO2 envelope.

You might be thinking this is too much hassle but remember a diluent flush is easy and quick to do and it puts breathable life supporting gas into your rebreather for most of your dives at most depths. Obviously if you are shallow with a hypoxic Trimix, then you would have to do the cell check with an oxygen flush, but with that proviso, it is good practice.

Rebreather Forum 3 Lecture; 'Thermal Physiology and Protection'

Rebreather Forum 3 - an international safety conference about rebreathers - was held in May 2012. Over the course of three days a number of presentations were given on many aspects of rebreather diving.

Dr Neal W Pollock, Neal Pollock, diving physiology, thermal physiology, breath hold diving, ice diving, thermal stress, DAN, Duke Dive Medicine, Divers Alert Network, Research Director, Rebreather Forum 3, RF3, Roz Lunn, Rosemary E Lunn, The Underwater Marketing Company, diving, scuba diving, technical diving, Fourth Element, Antarctic diving, ice diving, drysuit undergarments, thermal underwear, diving health, technical diving, HALO 3D, SITA, SITA Show, 2012 UK Diving Trade Show, Scuba Industries Trade Association

Dr Neal W Pollock, a diving physiologist from Divers Alert Network / Duke University gave a lecture on thermal physiology and protection.

Dr Neal W Pollock
9:15, Friday 18 May 2012, Boca Room III

“Diving is carried out in a wide range of environments and conditions. Thermal stress can be an important issue, particularly for the long exposures often associated with technical diving. Proper preparation can improve comfort, performance and safety. This presentation will discuss thermal stress, thermal protection, and implications for diving health.”

Dr Pollock's biography can be found here.

Photo Credit: Professor Simon J Mitchell