DUBAI, United Arab Emirates—An Emirati-flagged cargo ship, longer than a soccer field, sank in stormy seas off Iran’s southern coast in the Persian Gulf on Thursday, authorities said. Rescuers were trying to account for all of the vessel’s 30 crew members. Capt. Nizar Qaddoura, operations manager of the company that owns the ship, told The Associated Press that the Al Salmy 6 encountered treacherous weather. The choppy waters forced the vessel to list at a precarious angle and within hours fully submerged the ship. Emergency workers dispatched from Iran successfully saved 16 crew members, Qaddoura said, and civilian ships had been asked to help with the rescue efforts. Another 11 survivors made it into life rafts, while one person was plucked and saved from the water by a nearby tanker. Two crew members were still bobbing in the sea, he said. The crew consisted of nationals from Sudan, India, Pakistan, …