Milwaukee researchers offer perspective on challenges to locate missing submersible

MILWAUKEE (CBS 58) -- The search for a missing tourist submersible in the Atlantic Ocean continued Wednesday, June 21 as rescue and recovery teams confront challenges with the environment the vessel is believed to be located at.

U.S. Coast Guard officials shared an update with the public at a news conference Wednesday afternoon.

"A Canadian P-3 [aircraft] detected underwater noises in the search area," Coast Guard Capt. Jamie Frederick said. "As a result, [remotely operated vehicle] operations were relocated in an attempt to explore the origin of the noises. Although the ROV searches have yielded negative results, they continue."

CBS 58 spoke with local experts to learn more insight about the challenges faced by rescue and recovery teams.

"Sound travels more than four times faster in water than it does in air and sound is not attenuated or absorbed in water as it is in air," UW-Milwaukee School of Freshwater Sciences Professor Harvey Bootsma told CBS 58. "Sound travels very well. At the same time other frequencies like microwave frequencies or radio wave frequencies that are used by radios or GPS, they don't travel very well in the water."

Bootsma said sound is likely the best chance for the missing vessel to be found.

"I'm guessing that at least initially [rescue teams will] rely very heavily on sound either by trying to pick up sounds that are being sent out by the submarine that's down there or by using active sonar where you have a [remotely operated vehicle] that's sending out sound and looking for the echoes coming back to try to locate objects that are outside of the range of visibility," Bootsma said.

But there are still more challenges.

"Even if they find this submarine, retrieval will be difficult," Bootsma said.

Bootsma said the depth and pressure of the ocean will require sophisticated technology if the operation moves into a retrieval phase.