Revealing the Secrets of

Rebreather Scrubber Canisters

Draeger Dolphin divers at Morrison Springs, photo by Bernie Campoli

More than thirty years of research, testing, and computer modeling of rebreathers in a military laboratory have been condensed into a small, approachable monograph. Breakthrough is an affordable textbook unlike any other in the technical diving genre.

Clarke is a scientist and writer known for both his scientific research and writing, and his imaginative and stimulating science fiction writing. The Jason Parker Trilogy takes the reader from Deep Sea to Deep Space in an entertaining manner. While the scope of Breakthrough is far more limited, the author uses his skill as a writer to make it both entertaining and informative.

The intended audience is as diverse as the technical diving community itself. For those readers with an interest in math and computer science, there’s plenty of material to digest. For those more interested in the practical aspects of rebreather diving, there’s much to learn, even without plunging into long-forgotten mathematical equations.

So, there is literally something for everyone in this interesting and useful book.

Praise for Breakthrough

“One of the most important factors in rebreather design is scrubber efficacy. It is also one of the least well-understood. Generations of rebreather divers have guessed at how long their scrubbers will continue to scrub CO2 when using their equipment in environmental conditions outside of those in which they were tested… which is 99% of the time. Other users have incorporated personal use practices based on untested community lore and myths. John’s book dispels many of these unsafe practices and provides a base for making informed decisions regarding real-world diving practices vital for the rebreather diver. It is a “must read” for all serious users of this equipment.” Jeffrey Bozanic, Ph.D., Author of ­Mastering Rebreathers and Senior Technical Editor of the NOAA Diving Manual.

“BREAKTHROUGH fills the knowledge gap for mathematical and computer modeling of carbon dioxide (CO2) elimination in underwater breathing apparatus (UBA). A must-read for every UBA designer or diver interested in a better understanding of scrubber canisters and metabolic CO2 elimination.” Vincent Ferris, Assistant Program Manager for the Department of the Navy

“John Clarke’s new monograph “Breakthrough: Revealing the Secrets of Rebreather Scrubber Canisters” is truly that! The retired scientific director of the US Navy’s Experimental Diving Unit (NEDU) is the first to illuminate the inner workings of what has literally and figuratively, been a “black box”—the carbon dioxide (CO2) scrubber canister, which is a critical component of every rebreather—based on decades of existing and new research conducted by the author and the US Navy.

To accomplish this feat, Clarke derives a set of deterministic, stochastic, and visual models that enable us to virtually see and understand the underlying physical processes carried out by a CO2 scrubber and how they are affected by the diver. With the help of these tools, he is able to answer important, long-standing, and practical questions surrounding scrubber use and the impact of numerous factors on scrubber efficacy and duration, including temperature; scrubber packing and insulation, absorbent granule size and distribution, the differences of axial or radial scrubbers, as well as a host of biological variables.

Throughout the exposition, Clarke, a respiratory physiologist, presents the highly technical material in a fascinating, easy-to-absorb manner that makes it accessible to motivated readers. As such, Clarke’s “Breakthrough” should be required for every rebreather diver.” Michael Menduno/M2, Editor-in-Chief,

As Seen on Microsoft News

From Dive Immersion and Carlos Lander

Buy From

Barnes and Noble

Amazon U.S.

Amazon U.K.

Blackwell’s Scotland and England

Book Depository Europe, U.K, and elsewhere

Alibris UK (Textbooks)


Better World Books