Deep-sea explorers scouring the world's oceans for sunken World War II ships are investigating what they believe could be the third ship of seven lost to the Pacific during the Battle of Midway. Hundreds of miles off Midway Atoll, nearly halfway between the United States and Japan, a research vessel is launching underwater robots miles into the abyss to look for warships from the famed Battle of Midway. Weeks of grid searches around the Northwestern Hawaiian Islands have already led the crew of the Petrel to one sunken warship, the Japanese ship the Kaga. This week, the crew is deploying...