NS expert says sonar technology may have been key in locating the doomed Titan submarine

Underwater acoustic sensing may have been key to locating the wreckage of the submarine Titan, according to a Nova Scotia sonar expert.

The submarine bound for the Titanic lost communication with its surface craft on Sunday, sparking a massive international search.

The wreckage of the submarine was found on Thursday by a remote-controlled vehicle on the seabed about 500 meters from the bow of the Titanic. All five passengers and crew of the Titan are presumed dead.

That same day, the US Navy said it detected an acoustic “anomaly consistent with an implosion” in the area hours before the ship was reported missing.

It said it had shared the information with the Canadian Coast Guard and officials from OceanGate Expeditions, the company that operates the Titan.

Canada’s Department of National Defense confirmed on Friday that the data had been shared with them, but the “information assessment was not definitive” that the submarine was the source of the noise.

Joe Hood, the vice president of sonar processing for GeoSpectrum Technologies in Dartmouth, NS, said that in order to detect the noise, the U.S. Navy must have had a ship, submarine or possibly aircraft with sonar equipment within a few miles of the area. .

Hood said an underwater sound like an implosion happens quickly, but sound travels relatively slowly in water at about 5,000 feet per second.

Hyperbolic Confirmation

With multiple sensors on sonar equipment, Hood said the sound’s arrival time at each sensor can be used to estimate a position for the sound — a process called hyperbolic fixation.

But Hood said that even if the sound of an implosion were detected, analysis would be needed to determine the source.

“There are a lot of things that can make those short duration sounds in the water,” Hood said.

“It could have been someone hitting the hull to get attention, it could be the hull cracking, it could be the hull giving out, or it could be fish nearby making grunts and pops.”

Hood said it’s unlikely any of the sounds could have come from the Titanic itself, because there wouldn’t have been enough current at that depth and the wreck would have settled by now.

Once the search and rescue operation was underway, Hood said there were other possible ways to collect sound.

Underwater microphones

He said, based on reports he saw, that a CP-140 aircraft was on site with sonobuoys, a type of buoy with a radio transmitter and an underwater microphone on board.

Hood said sonobuoys are dropped into the water and the underwater microphone is deployed to a certain depth. Sounds detected by the microphone are transmitted by the transmitter.

He said it would have taken four or more sonobuoys to estimate the submarine’s position based on any noise coming from it.

Hood said the submarine’s situation was “strange for sure”.

He said planes and military submarines carry an underwater beacon — called a pinger — to alert people to their location if they go missing at sea.

“We’ve had similar situations in the past where people were trying to find these underwater pingers,” Hood said

“In this case, I don’t know if there was a pinger on board the submarine.”

The Transportation Safety Board of Canada said Friday it is launching an investigation into the operation of the Titan submarine by the Polar Prince Support ship. The Polar Prince is a Canadian registered vessel.