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

The US Coast Guard has deployed more ships and vessels to search for a submersible that disappeared on its way to the Titanic wreckage site. The search area is twice the size of Connecticut in waters 2 1/2 miles deep. The submersible had a four-day oxygen supply when it put to sea around 6 a.m. Sunday. The search is a race against time as the passengers' oxygen supply may run out as early as Thursday morning. The US Navy is sending a specialized salvage system capable of hoisting large, bulky, and heavy undersea objects such as aircraft or small vessels.