The History of Rebreather diving!

Longer dives, closer wildlife encounters, less gas cost—there are plenty for rebreather diving. Today, more divers than ever are enjoying what the silent world of rebreather diving has to offer them.

But rebreathers haven’t been around forever.

While the concept of recirculating breathing gas has been around for centuries, civilian rebreathers have only been available since the late 1990’s.

Let’s take a deep dive into the history of rebreather diving, from its early inception to modern day mixed gas rebreathers.

The Birth of Rebreather Diving

The history of rebreather diving begins as early as 1670. In this year, Italian Renaissance scientist Giovanni Borelli first came up with the idea of the rebreather system.

He thought that if air could circulate through copper piping, while being cooled by seawater, the condensation created would filter out impurities, such as carbon dioxide. While his invention never materialised, this was the first step for further developments.

After Giovanni, it took almost two centuries before a successful rebreather system was created. However, in the meantime, other scientific and diving related developments were made.

The First Scrubber

In 1726, Stephen Hale developed the first scrubber, allowing carbon dioxide to be removed from the breathing gas. This was created using a tartar and sea salt soaked flannel liner inside of a diving helmet, designed for surviving mine disasters.

It wasn’t until 1776 that Borelli’s first idea of the rebreather was tested. Freminet designed a diving helmet made out of copper, which used condensation as a scrubbing device. However, it was concluded that condensation failed to remove impurities.

Between 1773-4, oxygen was discovered independently in both England and Sweden, by Joseph Priestly and Carl Wilhelm, respectively. Experiments then followed, testing the use of soda lime and other compounds in scrubbers, and their effectiveness in keeping test subjects (animals) alive.

The First Rebreather

In 1878, the first closed circuit oxygen rebreather was finally born. 

Designed by Henry Fleuss, it consisted of two breathing tubes, a caustic potash filled breathing bag, a rubber mask and an oxygen tank.

The Fleuss rebreather demonstrated its capabilities in 1880, when Alexander Lambert used it to successfully close a flood gate submerged at 12 metres in the Severn River, with a total runtime of 90 minutes.

From Fleuss to World War Two

After Fleuss, development focused on making rebreathers for submarine escape, fire rescue and mine disasters. The Davis Submarine Escape Apparatus (DSEA) was one example of this. Another was the Oxylithe which used potassium and sodium peroxide as a CO2 absorbent, which in turn produced oxygen as a byproduct.

Other closed circuit systems that appeared around the early 1900s were the Proto, Salvus, Amphibian, and Mine Recovery Suit. In all cases, these rebreathers used only oxygen as a breathing gas and could only allow dive times of approximately 30 minutes.

In 1915, the Oxylite rebreather made a name for itself, after being used by divers in the movie Twenty Thousand Leagues Under the Sea.

During the same time period, developments were made in diving and decompression theory.

In 1878, Dr. Paul Bert published Barometric Pressure, discussing oxygen toxicity and decompression sickness. In 1908, Haldane began developing the first techniques for staged decompression. It wasn’t long until the British and Americans began experimenting with oxygen-helium (heliox) mixtures for deeper dives. In 1937, the first dive to 128 metres using heliox was made and in 1939 the US Navy made a successful salvage of the USS Squalus from 73 metres.

This brings us to the Second World War. Like with most wars, technological progress was sped up, which benefitted rebreather development.

Navy divers from France, Germany, Italy and the United Kingdom were tasked with driving underwater human torpedoes to enemy warships. They would then abandon these torpedoes, allowing them to explode. However, the problem they faced was oxygen toxicity. 

To counter the Italian Navy’s use of pure oxygen rebreathers in Gibraltar, the British began experimenting with Nitrox rebreathers. They used mixes between 32.5—60%, allowing their divers to go deeper and gain a strategic advantage.

Bernhard Dräger also helped the Germans develop their own rebreather technology, with developments such as the Bade-Tauchretter and the Gegenlunge.

That said, Navy divers still suffered from oxygen toxicity, which led to the establishment of 30 feet (9.1 metres) as the maximum operating depth.

The First Civilian Rebreather: The ElectroLung

Up until the 1970s, rebreather diving was mainly conducted by navy divers and other working professionals. In fact, during the second world war, rebreather technology and breathing gases were state secrets.

This began to change in the 1970s as well as when the Cold War came to an end.

In 1968, marine biologists Walter Starck and John Kanwisher put their collective genius together to create what would be the first civilian rebreather: the ‘ElectroLung.’ Starck and Kanwisher sold their idea to Beckman Instruments Company and began development.

In 1969, Skin Diver magazine editor Paul Tzimoulis published an article entitled ‘300 Feet on Computerised Scuba’, describing his deep dive using the ElectroLung.

Despite excitement in the diving community and Tzimoulis’s prediction that the ElectroLung “will undoubtedly revolutionise deep diving and rebreather diving technique,” a number of diver fatalities caused Beckman Instruments Company to shut down production.

While that was the end of the ElectroLung, it marked a significant development in civilian rebreather diving technology.

Throughout the 1970s, a range of rebreathers hit the market:

• Shadow Pac
• Westinghouse KSR-5GE Model 1400 (Mk-10)
• STM 300
• Sterling Electronics SS-1000
• Normalair-Garrett Deep Dive 500

However, none of these units were successful and quickly disappeared.

Cave Divers: Home-made Rebreathers

Restricted by gas volume, 1980s cave divers in the US and Europe realised they needed rebreathers if they wanted to push further into caves.

With limited options on the market, these cave divers took things into their own hands and began building their own rebreather units.

The first of these divers was Jochen Hasenmayer. In 1980, he constructed the Speleo Twin Rebreather 80 (STR-80). This was a dual rebreather, meaning you could bailout from the primary to the secondary rebreather—a useful function when kilometres-deep inside a cave.

Hasenmayer made some record-breaking dives using the STR-80. Most notably, he was the first sport diver (i.e. non-military or commercial) to reach a depth of 200m solo inside Fontaine-de-Vaucluse in France.

Across the pond, in the United States, cave diver Bill Stone started building his own rebreather—the Cis-Lunar—in 1984.

Stone’s primary goal was to build a rebreather that would get him through a sump at the end of a dry cave in Huautla, Mexico. For this reason, the unit needed to be incredibly tough. In 1987, the first Cis-Lunar rebreather, the Mark I, also known as the “Failsafe Rebreather For Exploration Diving” (FRED), weighed in at 93kg.

The Cis-Lunar was a success, enabling Stone to carry out a record-breaking 24 hour rebreather dive at Wakulla Springs, Florida.

Around the same time, Rob Palmer and Stuart Clough began using Carmellan mixed-gas rebreathers to explore the Blue Hole of Andros Island, Bahamas. These were dubbed ‘CR155’ rebreathers, which were originally military units that had been modified for biomarine rebreather diving purposes.

Likewise, at the end of the 1980s,  Olivier Isler—a Swiss cave diver—and Alain Ronjat—a French electronics engineer—built the RI2000 triple semi-closed rebreather. This allowed Isler to make three record-breaking push dives in 1989, 1991 and 1998 in La Doux de Coly, France.

Inspired by Isler’s successes, it wasn’t long until German cave divers Michael Waldbrenner and Dr Reinhard Buchaly built their own rebreather, the RB2000, allowing for even further exploration of La Doux de Coly. Buchaly was the founder and director of the European Karst Plain Project (EKPP), a DIR cave exploration group, who designed and used the RB2000 with great success.

Impressed by its capabilities, Woodville Karst Plain Project (WKPP) explorers and owners of Halcyon Dive Systems Jarrod Jablonski and Robert Carmichael, saw how the RB2000 could be used in their DIR exploration configuration. They wanted to replace the WKPP’s current rebreather, the Passive Variable Ratio-biassed Addition Semiclosed Rebreather (PVR-BASR), with the far simpler, intuitive design of the RB2000.

From then on, new rebreathers flooded the market, with increasing safety, technological advancements and capabilities. Rebreather diving began to grow significantly.

Let’s now take a look at the journey of some of these modern-day classic rebreathers.

Peter Readey’s PRISM Rebreather

While working in the petrochemical industry in the 1980s, British engineer Peter Readey worked alongside Clough, founder of Carmellan, to develop what would become the PRISM rebreather.

Despite running the unit through a series of tests and successfully using it at a depth of 122 metres for 24 minutes, it received little attention in the sport diving community due to fear of its complexity.

Peter set out to change this perception of rebreather diving and hit the road with his wife, Shas, in what would be a remarkable 18 month journey across the globe.

Peter and Shas set out, offering “Introductory Acquaintance Days” for all interested divers, for a fee of $99. These days would consist of a presentation on how the PRISM rebreather worked as well as a 20 minute try-dive. In less than 18 months, Peter and Shas had travelled through the US, UK, Sweden, Ireland, Egypt, Australia and New Zealand, enabling more than 1,500 divers to test their unit.

Given this remarkable journey, he was dubbed the “Johnny Appleseed of Rebreathers” by dive journalist Michael Menduno (in reference to the missionary John Chapman who similarly travelled the US planting apple seeds in the 18th and 19th centuries).

As a result of the publicity, Peter went into partnership with co-inventor of the microcomputer chip, Michael Cochran, in 1995. They set out to build a rebreather together, using Michael’s electronics knowledge and Peter’s rebreather diving expertise.

In a race to have the final product ready for the 1996 DEMA trade show, the two of them worked day and night, successfully creating what was to be the “Cochran PRISM II” rebreather. However, Cochran ran into legal issues and the PRISM II project was eventually abandoned.

Still undefeated, Peter and his wife moved to California, where they founded Steam Machines, privately training divers in the use of the PRISM as well as Mk 15.5 closed circuit rebreather (CCR). During this time, Peter experimented with new scrubber materials and changed the design of the loop. He and Shas trained a range of divers, from fish collectors to treasure hunters, and continued to offer Introductory Acquaintance Days.

In 1998, Steam Machines went into business with Carleton Technologies, a company specialising in military-grade rebreathers. This partnership enabled extra testing to be performed and new design features to be considered. Peter designed and built a new unit called the SM1600, combining PRISM electronics with the Mk 15.5 CCR. By 1999, Peter was ready to offer divers a new and improved PRISM rebreather for which they could put a deposit down.

Unfortunately, Carleton unexpectedly ended the partnership, leading to a brief delay in progress and almost causing the end of Steam Machines. If it weren’t for Peter and Shas’s determination, that would have been the end of the PRISM altogether.

Stringing together the capital they had, the two of them continued to work hard, motivated by the divers who still had deposits on the PRISM. In 2001, the PRISM was considered a new candidate to replace the US Navy’s rebreather.

Over the course of two years, the US Navy Experimental Diving Unit (NEDU) pushed the PRISM to its limits, running it through arduous testing. It came out on top, with a few design modifications, and was thought to be the new rebreather of the Navy. 

However, just as Carleton Technologies did in 1999, the US Navy abruptly ended the contract with Peter in 2003, for undisclosed reasons. Despite this setback, the NEDU partnership had improved the PRISM Topaz unit and in 2007, Peter’s 15 year dream finally came true. Founder of Oceanic and Hollis, Bob Hollis, offered to buy the PRISM from Peter at the Beneath the Sea exhibition in New Jersey. At that moment, the Hollis PRISM II rebreather was born.

With Peter’s unmatchable engineering abilities, Bob’s business connections and the Hollis brand’s trusted name, the PRISM II became one of the leading rebreathers of choice, known for its durability and ease of use. Fast forward to 2019, the PRISM II finally received CE certification.

AP Inspiration, JJ-CCR, Recreational Rebreathers and More

The story of Peter Readey’s PRISM rebreather is just one of many. While he was busy testing, designing, (re-testing, re-designing!) and jumping through many hoops, there were other rebreather engineers going through the exact same process.

In 1997, the very first CCR hit the civilian market: the AP Inspiration Classic. Two divers of the AP Inspiration, Jan Peterson and Jan Jørgensen, enthused by the unit but with dreams of something else, put their minds together to build a new CCR. With the help of Shearwater’s new GF dive computer as well as CE certification, they eventually launched the JJ-CCR in 2010. The JJ-CCR quickly became one of the leading rebreathers of choice, dubbed the “4×4 of rebreathers”: simple, rugged and fail-safe. GUE opted to use the JJ-CCR as their standardised rebreather of choice, modifying it to fit with their DIR configuration.

Around the same time, experiments with a rebreather designed for recreational diving continued. In 1995, the Dräger Atlantis and Grand Bleu Inc.’s Fieno-S were the only options available. Both units suffered from a few key design problems that reduced their popularity, including lack of PPO2 control in the loop, gas waste and buoyancy issues.

Both of these semi-closed rebreathers (SCR) were superseded by the AP Evolution, Poseidon MKVI and Hollis Explorer. While the AP Evolution and Poseidon MKVI are designed as Type R (recreational use) rebreathers which can also be upgraded for technical diving, the Hollis Explorer is purely for recreational usage. The Explorer takes out much of the human input, to reduce errors and make rebreather diving as simple as possible for the recreational diver.

Kevin Burr, the brains behind the Explorer, worked to design the Ouroboros rebreather in 2005. He also released the Sentinel in 2007, the first rebreather to include a gaseous CO2 sensor, winning him Eurotek’s Lifetime Achievement Award.

Within the last decade, the market has expanded to include sidemount rebreathers such as the T-Reb, KISS Sidewinder and Divesoft Liberty SM for cave diving, as well as lightweight frontmount rebreathers perfect for travelling, such as the Triton CCR.

The Future of Rebreather Diving

Today, there are more technical and rebreather divers than ever. With increasing helium prices, as well as a wide range of CCRs on the market, more divers than ever are shifting to rebreather diving.

With this trend comes a push for increasing rebreather safety, testing and innovation, making rebreather diving more accessible for everyone.

While open circuit diving will continue, rebreather diving will likely become much more commonplace.

In case you are interrested in rebreather diving here at Lagona Divers Technical, we offer training on two exploration-grade rebreathers: the X-CCR and the Triton CCR.
To become a part of the story of rebreather diving history yourself, drop us a message.