180209-N-ND254-004 BANGOR, Wash. (Feb. 9, 2018) CDR. Jeffery Yackeren, commanding officer, of the Ohio-class ballistic missile submarine USS Alabama (SSBN 731) tours with Deputy Secretary of Defense Patrick Shanahan during a training evolution. Alabama is one of eight ballistic-missile submarines stationed at the base, providing the most survivable leg of the strategic deterrence triad for the United States. (U.S. Navy photo by Mass Communication Specialist 2nd Class Nancy C. diBenedetto/Released)