Sonar Operators Shine During ANNUALEX

HMCS Ottawa’s starboard watch sonar operators gather for a group photo outside their restricted workspace. Back row: PO2 St. Pierre and LS Buss. Front row: OS Legg, AB Collett, and MS McPeak. Photo by Captain Jenn Jackson, HMCS Ottawa PAO

Captain Jenn Jackson, HMCS Ottawa PAO ~

Whomp! Whomp! Whomp!

That was the steady sound coming from the underwater telephone in HMCS Ottawa’s Operations Room throughout Anti-Submarine Warfare (ASW) serials conducted in ANNUALEX. Ottawa participated in the exercise from Nov. 10 to 19 during Operation Projection.

It was a combined exercise that included more than 25 ships, submarines, and aircraft organized into different task groups from the U.S., Australia, Japan, and Canada’s HMCS Ottawa.

The purpose of ANNUALEX was to improve interoperability and the capability for surface warfare, air defence and undersea warfare. The exercise included helicopter operations with the Australians and Japanese, replenishments-at-sea with the U.S. and Japanese, a visit from an Lt Cleo Scarce, a Royal Australian Navy officer, manoeuvres with the different task groups, ASW, and a war-at-sea phase.

Ottawa’s main focus during the exercise was ASW, and sonar operators played a pivotal role. It was the eyes and ears of sonar operators that were responsible for detecting, monitoring, and tracking “red force” submarines during the exercise.

“During ANNUALEX, we were tasked with using passive sensors, so we deployed our Canadian Towed Array Sonar System to detect the submarines,” says Petty Officer Second Class Sebastien St-Pierre, Sonar Control Supervisor in Ottawa. “From there it is up to us to know what is what in the ocean.”

The Canadian Towed Array System, or CANTASS, is designed to be towed up to two kilometers behind a Halifax Class Frigate, depending on oceanographic conditions, to detect and neutralize submarines by locating the sonar away from ship-generated noise.

CANTASS is a passive sonar that listens, but does not transmit noise into the ocean. Sonar operators monitor various frequencies using the CANTASS to determine if there is an enemy submarine present.

“For ANNUALEX, submarines were outfitted with an augmenter that added to its acoustic signature. Sonar operators were then provided a range of frequencies to listen for during the exercise, which we developed into ‘threat tonals’,” explained Master Seaman James McPeak, CANTASS supervisor in Ottawa. “These are the frequencies that identify a submarine from the numerous other noises in the ocean to which we listen. Knowing the frequency makes the training easier, but also increases the likeliness that a sub will be detected during the exercise, therefore increasing the training value.”

In real life, it is not as easy, says PO2 St-Pierre.

“The ship has to go to the Sonar Quiet State to reduce background noise, which means the simple things that make life more comfortable at sea are not permitted: no music or television, and devices such as treadmills cannot be used. It’s sustainable, but not fun for the crew to sustain over a period of weeks.”

During ANNUALEX, the work of Ottawa’s sonar operators resulted in the detection of four different submarines that were later neutralized by aircraft belonging to other ships in the task group.

“It’s exciting when you find a sub and are able to track it, especially considering where they operate and that their main priority is to hide and be undetectable,” says Able Seaman Nichelle Collett, a sonar operator in Ottawa. “It’s like the ultimate game of hide-and-seek, but much more intense when you consider we are training for real life warfare, which is definitely not a game.”

In the exercise, just like in a real scenario, once the team detected what appeared to be a submarine, the sonar control supervisor checked with the bridge to ensure there was no surface contact that could be making the noise. He then reported it to the underwater warfare officer with his assessment.

“Once the underwater warfare officer receives my report he will provide direction. If it is a sub, usually we will try to maximize our sonar placement and begin broadcasting by underwater telephone to ask the sub to identify itself or surface,” explains PO2 St-Pierre. “If there is a response, we will hear it back through the telephone, just like we hear the sounds of our own propellers.”

If the broadcasts go unheeded, the underwater warfare officer will make a recommendation to the Commanding Officer via the Operations Room Officer and a decision is made whether to engage the submarine or not.

Other options include coordinating with members of a task group and having the sub neutralized by aircraft.

“If the Captain had decided to engage the sub ourselves, then I would have calculated a firing solution and on command fired a pneumatically insufficient simulated (PIS) shot during the exercise,” explains Lieutenant(N) Andrew Campbell, Ottawa’s underwater warfare officer.

A PIS shot is a simulated shot that is too small to fire an actual torpedo if the tubes were loaded, but still engages the electronics and ejects air from the tube with a distinctive ppissht sound.

“Because our sonar operators detected the submarines before they came within range of the ship, we did not have to escalate to that point. Due to the threat subs can pose to surface ships, early detection of them is key to keeping the ship and crew safe,” said Commander Alex Barlow, Ottawa’s Commanding Officer. “During ANNUALEX, our full underwater warfare team demonstrated their skills, gained experience working with partners’ submarines and supported the combined effort of the full crew throughout the exercise. Ottawa completed ANNUALEX demonstrating its crew is professionally trained, adaptable and flexible. I am very proud of their work – both during this exercise and throughout our deployment on Operations Projection and Neon.”

Ottawa deployed to the Asia-Pacific region on Operation Projection Aug. 6 to conduct forward naval presence operations in the region, as well as conduct cooperative deployments and participate in international naval exercises with partner nations. During the deployment they also supported Operation Neon, Canada’s contribution to the enforcement United Nations Security Council Resolutions 2375 and 2397. The ship returns home mid-December.