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Assessing the State of Our Rebreather Nation

In two weeks time, many of the leaders of the global civilian and military rebreather diving communities will gather to assess the state of our rebreather nation. To prepare the groundwork, we thought it would be useful to revisit the results of the last Rebreather Forum (RF3), which was held in 2012, as a benchmark to help us assess where we are today and what still needs to be addressed. Here is InDEPTH’s chief Michael Menduno’s report on RF3, the conference Consensus Statements, and some additional resources to keep you in the loop.



By Michael Menduno

In a little more than two weeks, several hundred rebreather diving professionals representing the rebreather nation—read tekkies, scientists, hyperbaric docs and military and governmental rebreather divers—will converge on the island of Malta for the Rebreather Forum 4 (RF4) symposium to share and discuss the latest science and thinking about rebreather diving safety and performance. 

The resulting three days of presentations and deliberations will be transcribed and edited into a scientific proceedings that will be published later in the year, along with the release of broadcast quality videos of the RF4 presentations. 

Accordingly, we thought it would be useful to revisit the results of the last symposium, Rebreather Forum 3.0 held in May 2012 in Orlando, Florida, to better understand where we were 10 years ago, what the key issues were then, and exactly how far we have come—or not come—on particular issues at hand.

First, we are republishing my report from RF3, which provides a detailed overview of the critical rebreather issues and discussions of the time. Rebreather safety, checklists, minimum training standards, recreational rebreathers, anyone, and what about oxygen and carbon dioxide measurement?

Second, we are reposting a seminal paper by ex-British Special Forces instructor turned tech shipwreck explorer Paul Haynes. The paper, which was originally published in the Diving Hyperbaric Medicine (DHM) V46 No.4, DEC 2016 addresses diver airway protection focusing on mouthpiece retaining straps (MRS). 

Haynes led the discussions on airway protection and the use of MRS, at RF3. However, there was not a consensus on the effectiveness of MRS to prevent drowning. Accordingly, the Forum identified as research questions whether an MRS would provide protection of the airways of an unconscious diver, and the efficacy of full face masks for tech divers. These were adopted in the Forum Consensus Statements (see below). Since that time, two papers have been published; one a study of French Military divers, the other about the Thai kids cave rescue, which demonstrated the efficacy of MRS and FFM in preventing drowning.

Haynes was also one of the movers behind the Rebreather Training Council’s (RTC)’s MRS safety initiative which was launched in 2021. However, it is fair to say that MRS has not yet been widely adopted by the tech community. As one CCR instructor trainer explained to me, “Why do you need one if you properly analyze and monitor your breathing gas” Why indeed? I decided to highlight the story this month, as MRS will likely be an important discussion item at RF4. 

Finally, we are posting the complete RF3 Consensus Statements with discussion, which were compiled during the final sessions of the Forum that was led by Dr. Simon Mitchell. Note that these represent the conclusions and consensus points arrived at by the assembled RF3 delegates with respect to various topics. It should be noted that progress has been made on numerous consensus point items.

Not surprising, as you read through the RF3 conference report and group discussion, you will notice that many of the individuals who were primary contributors at RF3 are still in the game and will be presenting at RF4. Unfortunately, Bill Stone, who could arguably be called the Godfather of Tech Rebreathers, plans to be underground at Sistema Chéve in Mexico during most of the month of April as part of his annual trek to the underworld— a pilgrimage he has been making for more than three decades. He will be missed! 

Note, we have also included a link to Rebreather Forum 2 (RF2) Findings & Recommendations (1996). At the time, Drager had released its Atlantis semi-closed nitrox rebreather a year earlier, and the AP Diving’s Buddy Inspiration was still a year away. Many of the conclusions are still relevant today. There were no proceedings from the original Rebreather Forum, only a report. Taken together they document the development of rebreather diving in the sports diving community.

We will be publishing a preliminary report on RF4 in the May issue of InDEPTH. In the meantime, I look forward to seeing some of you in Malta in a few weeks. For the rest, if you suddenly feel that urge that you can’t afford to miss it, I hope that you will come on down.—M2

Improving Rebreather Safety: The View from Rebreather Forum 3 (2012)

Improving rebreather diver safety was the primary focus of RF3, in response to the fact that, as of 2005, an average of about 20 rebreather divers were dying globally each year. These numbers compared to about 120-140 annual fatalities of open circuit divers in Australia, Europe and the US, which represented the bulk of the sports market. This led anesthesiologist and rebreather diver Andrew Fock to estimate that the risk of dying on a rebreather was 5-10x that of open circuit scuba. The report, prepared by InDEPTH chief Michael Menduno goes on to discuss the key equipment, training, and human factors issues of the day, circa 2012. Retro-Thursday people?

Increasing The Probability Of Surviving Loss Of Consciousness Underwater When Using A Rebreather

With divers soon returning to the loop, the Rebreather Training Council (RTC) is currently considering a number of initiatives to improve rebreather diving safety. One of those is to recommend the use of mouthpiece retaining straps to prevent drowning in the event of loss of consciousness (LoC). Accordingly, we offer this seminal paper by ex-British Special Forces dive instructor turned tech instructor trainer Paul Haynes on their efficacy and use. Can you or your mates survive a LoC underwater?

Rebreather Forum 3.0 Consensus Statements (2012)

The RF3 Consensus Statements represent the findings of the Forum, and were arrived at through interactive session(s) moderated by Dr. Simon Mitchell, who prepared the statements. Questions and answers, and the discussion are included after each consensus statement.

Rebreather Forum 2.0 Findings & Recommendations (1996)

Note that these findings & recommendations were developed just prior to mixed gas closed circuit rebreathers being introduced to the sport diving market.

Free Download

aquaCORPS #7 C2 (Closed Circuit) was published in January 1994 just prior to the 1994 tek.Conference and DEMA show held in New Orleans, LA. The issue focused on rebreather technology, and we planned it as a primer in anticipation of aquaCORPS Rebreather Forum, scheduled to be held in Key West, FL, May 1994. At the time, there were only a few dozen rebreathers in the hands of sport divers.


Behind Closed Circuits: A Documentary by aquaCORPS and Docent Films (1993)

A spirited historical teaser highlighting the state of the Rebreather Nation in 1993! 


Diving & Hyperbaric Medicine: Analysis of recreational closed-circuit rebreather deaths 1998-2010 by Andrew Fock. 2013, Diving and Hyperbaric Medicine

Rebreathers & Scientific Diving, Catalina Is., CA February 2015:
Rebreathers & Scientific Diving Workshop Proceedings 

Rebreather Forum 3.0, Orlando, FL May 2012:
Rebreather Forum 3 Proceedings

Rebreather Forum 2.0, Redondo Beach, CA September 1996:
Proceedings of Rebreather Forum 2.0

Rebreather Forum 1.0, Key West, FL May 1994:
In The Loop: A Report on aquaCORPS Rebreather Forum

Michael Menduno/M2 is InDepth’s editor-in-chief and an award-winning journalist and technologist who has written about diving and diving technology for more than 30 years. He coined the term “technical diving.” His magazine “aquaCORPS: The Journal for Technical Diving” (1990-1996) helped usher tech diving into mainstream sports diving, and he produced the first tek.Conferences and Rebreather Forums 1.0 & 2.0. In addition to InDepth, Menduno serves as an editor/reporter for DAN Europe’s Alert Diver magazine, a contributing editor for X-Ray mag, and writes for He is on the board of the Historical Diving Society (USA), and a member of the Rebreather Training Council. Menduno is the organizer of Rebreather Forum 4.


The Aftermath Of Love: Don Shirley and Dave Shaw

Our young Italian poet-explorer Andrea Murdoch Alpini makes a pilgrimage to visit cave explorer Don Shirley at the legendary Bushmansgat cave in South Africa. In addition to guiding the author through the cave, Shirley and Alpini dive into history and the memories of the tragic loss in 2005 of Shirley’s dive buddy David Shaw, who died while trying to recover the body of a lost diver at 270 m/882 ft. The story features Alpini’s short documentary, “Komati Springs: The Aftermath of Love.”




Text by Andrea Murdock Alpini

Inside the Black Box of Boesmansgat’s dive archive (Dave Shaw memorabilia)

🎶 Pre-dive clicklist: Where is My Mind by Pixies🎶

South Africa, Komati Springs.

On October 28, 2004, two cave divers and long-time friends, Don Shirley and David Shaw, planned a dive at Boesmansgat (also known in English as “Bushman’s Hole”) a deep, submerged freshwater cave (or sinkhole) in the Northern Cape province of South Africa. Dave dove to 280 meters, touched the bottom and started exploring. At that time, Shaw had recently broken four records at one time: depth on a rebreather, depth in a cave on a rebreather, depth at altitude on a rebreather, and depth running a line. While on the dive at Boesmansgat, he found a body that had been there for nearly ten years, 20-year-old diver Deon Dreyer. 

After obtaining permission to retrieve the body from Dreyer’s parents, the two friends returned three months later. They enrolled eight support rebreather divers (all of whom were close to Don) and Gordon Hiles, a cameraman from Cape Town, who filmed the entire process—from the preparation on the surface to the operation at the bottom of the cave. The surface marshal was Verna van Schaik, who held the women’s world record for depth at the time. Little did they know that Dave would not come back from his 333rd dive, one that he himself recorded with an underwater camera. 

Researchers have determined that while attempting the retrieval, Dave ran into physical difficulties with the lines from the body bag and the wires from the light head. The physical effort of trying to free himself led to his death for what is believed to be respiratory insufficiency (see video below). Don Shirley nearly died as well, and apparently was left with permanent damage that has impaired his balance. 

Nearly 20 years later, our own Andrea Murdock Alpini visits Don and has this to say: 

Dave and Don before a dive.

February 2023—I arrive at the mine owned by cave expert and pioneer of deep diving, Don Shirley. The place is fantastic—the wild nature, the warm water, and the dives are amazing. Every day I spend at least 230 minutes underwater, filming the mines and what is left of man’s influence in this beautiful and God-forgotten corner of Africa. Every day I have time to talk, plan dives, and prepare the blends together with Don Shirley. 

The following is a part of the story that links Don Shirley to South Africa. Stories and places intertwine between Komati Springs, Boesmansgat (or “Bushman’s Hole”) and then the fatal dive with his friend Dave Shaw. 

Monkeys arrive on time every 12 hours. They showed up last night at about 5:00. They came down from the trees in large groups. They start playing, throwing themselves from one branch to another, chasing each other. Mothers hug their little ones. Some of them play with oxygen cylinders, the smaller ones instead with methane gas tanks, the ones we use for cooking. We are surrounded by gas blenders of all kinds. 

A herdsman’s hat rests on the workbench. Two hands with delicate, thin skin take adapters, cylinders, and whips.They open and close taps. Notebooks report all the consumption for each charge, strictly written in liters with the utmost precision. Impressions: An Amaranth t-shirt, an unmistakable logo, that of the IANTD. A pair of jeans and then some boots. He has a slight physique, he is lean and athletic with a beard that is white now, and a few days’ old. 

While he works carefully, I do not disturb him, for I know well that when mixing, one is not to be interrupted, at least this is so for anyone who loves precision. Then, when he’s done, we have time to talk a little bit together.

Don Shirley with the author planning a dive at Komati Springs

We sit at his desk and then go to the board to plan the dive in the mine.

Don shows me the map of the first level. He explains some important facts to me, then his hands pull out a second sheet with the plan redesigned from memory of the second level at 24 m/70 ft deep. “This is the guitar level,” he says. 

At first I don’t understand. He chuckles. I look at the shape he drew and, yes, that floor plan is a cross between a Fender Stratocaster and a Picasso guitar. Anyway, it’s a guitar, no doubt.

We begin planning the dive together. It’s exciting to hear him talk; he speaks in a soft, elegant tone, and it moves me. I look at his index finger moving. I listen to his words, but I also look at his eyes. 

He gives me some advice but also tells me, “This mine is more similar to a cave. I have left it as it is. I want people to explore it and not follow any lines.”

Freedom of thought, plurality of choices. Acceptance of risk, inclusion of the other in what belongs to you. It’s clear that Don’s vision of diving is uncommon. Freedom is beautiful, but it is the most dangerous thing there is, if mishandled. 

An old map of Komati’s mine site

The next day, we have an appointment at 7 o’clock at the lake. Before diving this morning, we saw where the “Tunnel of Love” originates on the surface, a curious gallery which I came across underwater. There are two parts of the mine that survived the destruction of the mining facility after its closure. One of these is the tunnel where we are going, the other part is perched in the middle of the mountain.

Don explains that the tunnel is now frequented by the wild animals who go to drink there, so we follow their trail. The water has flooded everything up to just a few meters below the surface of the bush. Don cuts the underbrush that makes the path difficult. He wears his faithful herdsman’s hat and never takes it off. The ground begins to tilt slightly, a good sign that we are about to arrive. A series of stones suggest that here the path has been paved. “It was covered in wood,” Don explains.

The path that started from the building where the miners lived is now demolished. Following it, we arrive at what was called “The Tunnel of Love.”

The tunnel that was the mine’s main entry point. Narrow and difficult, the tunnel led to level one—now underwater at a depth of 18 m/60 ft.

We turn on the headlamps and enter. A small colony of bats flaps its wings upon our arrival. The water touches our boots. Some roots filter from the rock and stretch to the resurgence. The scenery is evocative.

The author and Marco Setti in the end of their explorations at Komati Springs

Don kneels, peering at the water, and something. He looks at the water and something changes within him. Something has changed in our shared dialogue.

It’s as if Don takes on another language as he speaks. He always looks straight ahead. His vocabulary changes, and with it his tone of voice. We talk about politics, economics, the future of Komati Springs, the origin of the name of the place, the history of the mine, but we never mention two topics: diving and Dave Shaw.

Don’s a real caveman. I know that those who love caves are not ordinary people. We who do are a little bit mad to do what we do and love, but he’s different. He is comfortable here; he has found his dimension.

I remember asking him a question when we were inside the Tunnel of Love, breaking one of the long silences: “What thoughts are going through your mind?” He seemed to have reached a meditative state, a kind of catharsis. He replied, “I am just relaxing. This is a peaceful place. “

Around nine o’clock, we travel again to the lake, leaving the dry caves behind. 

Exploring a tunnel in the flooded mine.

The first dive lasted 135 minutes, the second 95 minutes. Once the equipment is set up, I return to the cottage to dry everything and recharge the cylinders.

Don’s hands this time are again without gloves. Before we start mixing, we walk into his office.The walls are lined with articles he has published over the years. 

He shows me the medals for valor he got when he was on duty in the British Army. When we return to a small corridor that acts as a barrier, my eyes fall on two photographs. “Is that Dave?” I ask. “That’s him. We were here in Komati,” Don tells me. “You see? This is his hat,” and he points to what is on his head.

The pond above the mine and wild nature who surrounds Komati. A real wild South Africa scenario.

The Consequences of Love

These are the consequences of love, I think. A friendship that transcends time, life, but also death.

It’s time to prepare the blends for tomorrow. As the oxygen pumps out, Don asks me, “Have you ever seen our Boesmasgat’s diving slates?” Obviously, I had never seen the decompression tables of that famous and tragic dive to 280 m/920 ft depth at 1,600 meters (nearly 5,000 feet) altitude.

“Hang on a sec.” Don picks up a small black box with a yellow label and brings it to me. He opens it. “These are the original dive charts. These are mine; these are Dave’s.” The box also contains the famous blackboard with the inscription, (“DAVE NOT COMING BACK”) from the documentary, as well as a pair of underwater gloves used in that dive, and then the heirloom of his CCR computer that broke due to excessive hydrostatic pressure.

He exits the room. He leaves me with those emotionally charged objects in my hands. I can’t see them any differently. They obviously have historical value; but, for me, the human sense prevails. I look at the decompression tables, touch the gloves, and think about the hands that wore them, that read the various whiteboards, and I imagine the scenes of that time.

Early days of explorations at Komati Springs, Don Shirley with Dave Shown and their team 
Don Shirley wearing Dave’s old hat while scouting out the Tunnel of Love

I place everything back in the box. I hand it to Don as I would hand him a precious urn. In part, it is one. I find it hard to express myself in that moment. He understands why.

At this point I ask him, “What was the true meaning of that extreme dive that Dave wanted to do? Why did he do it?”

“He just wanted to explore the bottom of that cave,” Don said. “Wherever Dave went, he wanted to get to the bottom. That’s how we’ve always done it together. So that’s what we did here at the mine.” 

Don then tells me a series of details and information about that place, about the geological stratification of the cave; he talks a little about the owner of the land where the famous sinkhole is located, and finally he talks about many other aspects of their failed dive. I promised to keep it to myself, and I will do so, forever.

Such is a connection that endures over time.


Wikipedia: Dave Shaw

YouTube: Diver Records Doom | Last Moments-Dave Shaw

Wikipedia: Dave Not Coming Back (2020) A critically acclaimed film that centers on diver Dave Shaw’s death while attempting to recover the body of Deon Dreyer from the submerged Boesmansgat cave in 2005.

Shock Ya: Don Shirley Fondly Remembers Scuba Diving with David Shaw in Dave Not Coming Back Exclusive Clip

Outside: Raising the Dead (2005) by Tim Zimmerman

Other stories by the prolific Andrea Alpini Murdock:

InDEPTH: Finessing the Grande Dame of the Abyss

InDEPTH: Hal Watts: Plan Your Dive

InDEPTH: I See A Darkness: A Descent Into Germany’s Felicitas MineInDEPTH: Stefano Carletti: The Man Who Immortalized The Wreck of the Andrea Doria

Andrea Murdock Alpini is a TDI and PSAI technical trimix and advanced wreck-overhead instructor based in Italy. He is fascinated by deep wrecks, historical research, decompression studies, caves, filming, and writing. He holds a Master’s degree in Architecture and an MBA in Economics for The Arts. Andrea is also the founder of PHY Diving Equipment. His life revolves around teaching open circuit scuba diving, conducting expeditions, developing gear, and writing essays about his philosophy of wreck and cave diving. He published his first book, Deep Blue: storie di relitti e luoghi insoliti (2018) and IMMERSIONI SELVAGGE, published in the Fall of 2022.

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