An international mission rescued both occupants of a sunken submersible off the coast of Ireland in 1973 with just 12 minutes to spare. The men had spent three days in darkness and silence.

Retired U.S. Navy submarine Capt. David Marquet says crews would need to locate the vessel then bring it to the surface to unlatch it. He puts the odds of passengers' survival at "about 1%."

A 28-year-old man fell overboard from the Carnival Valor cruise ship hours before he was reported missing off of the southeast Louisiana coast. The passenger is in stable condition.