New rebreather tested in open water

Lt(N) Michael Cormie 
Canadian Forces Environmental Medicine Establishment

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The Experimental Diving and Undersea Group along with Clearance Divers from both Fleet Diving Unit (Atlantic) and FDU (Pacific) deployed to CFB Esquimalt Feb. 27 to March 6 to conduct open water testing and Initial Cadre Training on a new rebreather.

The Canadian Underwater Mine-Countermeasures Apparatus – Version Electronic (CUMA VE) is a significantly updated version of the legacy rebreathers, CUMA V2 and CCDA, which are at the end of their service life.

“The CUMA VE will allow Clearance Divers to continue to carry out their naval mine warfare functions, as it provides breathable gases to the diver from a non-magnetic and nearly silent apparatus,” explains Lieutenant Commander Nicolas Percy, Project Officer at Experimental Diving and Undersea Group (EDUG). “These factors are important when getting within inches of sea mines that may be triggered by magnetic and acoustic influences”

Rebreathers work by recirculating the gas a diver breathes, chemically scrubbing out the CO2 that has been exhaled and adding oxygen to make up for the gas the diver metabolizes. They are far more efficient in their use of breathing gases, and unlike SCUBA equipment, do not produce bubbles, which helps keep them quiet while extending the diver’s time on task.

“These sets provide significantly more information to the diver than our current equipment,” explained LCdr John Keenan, OC of EDUG. “The drills are simpler for the diver, and they have improved safety features. This means divers will be more confident in our equipment while allowing us to focus on the primary task of removing mines and other ordnance from the underwater battle space.”

CUMA VE underwent initial unmanned testing in Toronto during the fall of 2021 with the initial human testing and Initial Cadre Training happening at Seneca College’s 12m diving tank, and EDUG’s Diving Research Facility, a wet and dry hyperbaric complex co-located with the Defence Research and Development Canada Research Centre in November and December 2021.

This permitted the initial human testing to be conducted under realistic but highly controlled conditions, allowing divers to develop skills, comfort, and confidence in the equipment while concurrently evaluating the performance of the system before taking it into an open ocean environment.

The CUMA VE is anticipated to be ready for limited operational service by mid-2022.