180304-N-IA905-1070 ARABIAN GULF (March 4, 2018) Master-at-Arms 1st Class Robert J. Schmidt explains how to perform a mach takedown during a sentry course aboard the Arleigh Burke-class guided-missile destroyer USS Preble (DDG 88). Preble is deployed to the U.S. 5th Fleet area of operations in support of maritime security operations to reassure allies and partners and preserve the freedom of navigation and the free flow of commerce in the region. (U.S. Navy photo by Mass Communication Specialist 3rd Class Morgan K. Nall/Released)