The Coast Guard used tools ranging from sonar technology to aircraft to search below the water and on the ocean's surface. John’s, Newfoundland, the Joint Rescue Coordination Centre in Halifax, Nova Scotia, said. Coast Guard in Boston partook in the search for the missing submersible, which was reported overdue Sunday night about 435 miles south of St. John Mauger, commander of the First Coast Guard District, said at a Thursday press conference, adding that it was too early to tell when the Titan imploded. The Titan's debris was found on the sea floor about 1,600 feet from the Titanic's bow, Rear Adm. The search for a missing Titanic tourist submersible, carrying five people, concluded Thursday when officials discovered debris from the watercraft near the Titanic wreckage site and determined it suffered a 'catastrophic implosion.'' Watch Video: Search for five in missing Titanic submersible comes to an end