US Coast Guard upgrades search capabilities with new ships and underwater vehicles.

The US Coast Guard is bringing in more ships and underwater vessels to search for a submersible missing in the North Atlantic after detecting underwater sounds, including banging noises, that provided a glimmer of hope three days after the Titan disappeared while bringing five people down to the wreck of the Titanic. The exact location and source of the sounds were not yet determined, but it allowed searchers to focus on a more narrowly defined area. The vessel is estimated to have as little as a day’s worth of oxygen left if it is still functioning.