https://apnews.com/article/missing-titanic-submersible-851bcfb36dfb4d58aa43daeda481905d > BOSTON (AP) — Eight hours. And within them, many unanswered questions. > About an hour and a half after it dipped below the North Atlantic, a submersible on an expedition to view the wreckage of the Titanic lost communication with the surface. It would take another nearly eight hours before the Canadian research icebreaker Polar Prince, supporting the Titan submersible, reported it missing to the Coast Guard — a report that triggered the international rescue effort that was ongoing Thursday.