U.S. Navy equipment listening for Flight 370's 'pings'

(CNN) – Investigators have searched by satellite, by plane, and by ship, combing for any remnants of missing Malaysia Airlines Flight 370.

Now, the search continues underwater.

Australia's naval vessel Ocean Shield is towing behind it a black box locator, courtesy of the United States Navy, that will try to detect "pings" sent out by the plane's cockpit voice and flight data recorder.

Searchers are desperately hoping those pings are still transmitting from the missing Boeing 777.

CNN's Will Ripley reports from a boat ten miles off the coast of Perth, Australia, in the Indian Ocean.