Rescue crews are racing against the clock to find Titan, a missing submersible in the North Atlantic Ocean. The five-passenger vessel was diving to the wreck of the Titanic when it lost communication on Sunday. OceanGate Expeditions, which runs the voyage, estimates Titan has up to 96 hours of oxygen. The U.S. Coast Guard estimates they have 40 hours of life-support capacity remaining, as of 1 p.m. ET Tuesday. With the famous shipwreck sitting more than 3,800 metres below the surface, retired fo