Desperate search for missing submersible near Titanic intensifies with new underwater vessels and sounds detected.

The US Coast Guard is using new ships and underwater vessels to search for a submersible that vanished while bringing five people down to the wreck of the Titanic. Underwater noises were detected by a surveillance aircraft, and officials are searching an area twice the size of Connecticut. The area of the North Atlantic where the Titan submersible went missing on Sunday is prone to fog and stormy conditions, making it an extremely challenging environment to conduct a search-and-rescue mission.