President Trump is replacing his Secretary of the Navy as the blockade of the Strait of Hormuz continues as a key chokepoint in the war against Iran. John Phelan is leaving, effective immediately, and Undersecretary Hung Cao will become Acting Secretary of the Navy, the Pentagon said Wednesday in a surprise announcement. No reason was given for his departure. “Secretary of the Navy John C. Phelan is departing the administration, effective immediately,” Pentagon spokesman Sean Parnell announced.