In-depth training for clearance divers

LS Litter helps fellow diver LS Marc Andre Ouimet get into the water for a dive

LS Litter helps fellow diver LS Marc Andre Ouimet get into the water for a dive.

Nine sailors are hoping to join an elite group of divers this August by enduring the rigours of the year-long Royal Canadian Navy Clearance Diving Officer/QL5A Clearance Diver course.

Last Tuesday off Brentwood Bay, Lookout joined the sea portion of the CUMA Rebreather phase from this specialty course to talk to the trainers and divers to find out more about this specialized dive training, which is only offered at Fleet Diving Unit Pacific (FDU(P)).

“There are only 120 clearance divers in Canada,” said senior dive instructor PO1 Sean Ratz. “The students find this course challenging, rewarding and they also love bonding and working as a team,” he said. “It’s a difficult course, and the learning curve is steep.”

Seven Leading Seamen and two officers, including one exchange officer from the Irish Navy, are taking this course.

The course began in September and since then divers have conducted pool training at Commonwealth Pool, navigated a one kilometre underwater rope course and completed a series of work-ups for deep dives to 21, 30 and 45 metres. They have also learned to use new equipment and apply theories learned in the classroom.

Now at sea for a two week course, they are aiming for the maximum depth of 81 metres using Canadian Underwater Mine Apparatus (CUMA) rebreather dive gear. The CUMA Rebreather uses a mix of helium and oxygen, which allows people to dive much deeper than traditional SCUBA air supply.

“The CUMA rebreather allows you to dive deeper and are much quieter and less invasive acoustically and magnetically,” said Irish exchange officer SLt Shane Mulcahy. “We have naval divers in Ireland, but there is no rebreather training like this. This training allows us to carry out tasks like mine clearance with significantly less risk of activating the device.”

He added, “I am finding this course very intense, physically and mentally, as we never know what is coming next and what the day will bring whether it is physical training, compass dives, night dives or morning swims.”

Student LS Charpentier says he has enjoyed learning the science and physics behind the equipment.

“You don’t produce any bubbles with rebreathers, and you spend more time listening to your thoughts. With diving, there is a lot of non-verbal communication and you get really good at communicating with your buddy without using words,” he said. “You also learn to trust your supervisor and your kit, which is very important. A big part of diving is mental attitude.”

As the divers descend beneath the surface to 42 metres and deeper, they practice rebreathing techniques, safe return to surface techniques and emergency procedures. The support crew is also practicing its skills, ensuring the rebreather lines are working and the gases are mixed properly. Too much or too little of either helium or oxygen could be deadly.

The CUMA rebreather is equipped with a sensor that monitor the status of the gases. The indicator light can be green or red.

“If a red light goes off in the corner of the diver’s mask they must count to 15, see if their equipment is still delivering the proper amount and percentage of helium and oxygen,” says PO2 Rob Majore. “If the light remains red,  then the diver must give the appropriate signal with his lifelinel, switch on his emergency bailout system and return to the surface. The signal will allow the supervisor to send a standby diver to assist the diver to safely return to the surface.” 

Once on the surface, if the diver is suffering from decompression  illness,  the crew would  utilize the onboard recompression chamber to return the diver to pressure. The support crew can bring him back safely to the surface under the care and advice of a consultant of diving medicine who is part of the specialized crew onboard the dive tender while conducting deep diving training.

Clearance divers are called on to remove bottom mines in shipping lanes, render ordinance safe and dive under ships to assess and repair battle damage. This type of diving was used in the 1998 Swiss Air plane crash in which clearance divers worked to recover pieces of the aircraft, including the black box, from the ocean floor after the crash. 

“My most memorable experience diving with the Canadian Forces was last year in Estonia,” says PO1 Ratz. “We were deployed as a team of six, clearing the Baltic Sea of mines. We did 98 dives in two weeks to clear mines which were set in the Second World War. It was very rewarding to speak with the locals and hear about their appreciation for the work we were doing,” he said.

To become a clearance diver, students must first be a Ship’s Team Diver, Port Inspection Diver or a Combat Diver. Potential candidates are screened during a two week selection phase at FDU(P) to see if they have what it takes and so they can decide if they wish to pursue it. If selected, they undergo the 11-and-a-half month clearance diver course.

“I was drawn to this field because it’s ever changing,” says LS Charpentier. “I was a port inspection diver for the past 12 years as a reservist and I finally decided I wanted a full-time career in diving. I can work in EOD [Explosive Ordinance Disposal], regulator repair, mine counter measures or battle damage repair, so there is always a lot to learn,” he says.

“During this course we are not only learning rebreather diving, we are also learning everything about the trade like being on a ship’s crew, duty watch, anchoring and driving the many different small boats. It keeps your mind focused all the time, whether you are driving the boat or operating the recompression chamber. There is always lots to learn and that is what I love about being a diver,” he said.

After graduation on Aug. 9, four clearance divers and one officer will remain in Esquimalt and the other three will return to their posts in Halifax. Each year six to eight non-commissioned members and one to four officers take this course.

-Shelley Lipke, Staff Writer

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  1. Lookout says:

    For information on how to join. Please visit,

  2. amir hossein hazeri says:

    hi ..i m deep diver…..i was commander of diving training navy school and want to join your diving school ….

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