WASHINGTON — The Navy is sending dozens of small unmanned submarines to the Persian Gulf to help detect and destroy mines to prevent Iran from closing the Strait of Hormuz in the event of a crisis, U.S. officials said.  The Strait of Hormuz is the passageway for a fifth of the oil trade worldwide. 

The tiny SeaFox subs carry a television camera, homing sonar and an explosive.  The US also has four MH-53 Sea Dragon helicopters, four minesweeping ships, two aircraft carriers and a squadron ...