James Cameron’s ‘Titanic’ expert weighs in on the ‘unusual’ missing sub

Parks Stephenson, the Titanic explorer who worked with director James Cameron on his classic romance drama, worries Sunday’s disappearance of a tourist submersible on an expedition to the wreckage “has the potential to be a major tragedy.” “No matter what you may read in the coming hours, all that is truly known at this time is that communications with the submersible have been lost and that is unusual enough to warrant the most serious consideration,” Stephenson wrote in a Facebook post Monday. “I am most concerned about the souls aboard,...