U.S Navy Gas Turbine Systems Mechanical 2nd Class Derick Simpkins examines a fuel sample after conducting a bottom sediment water test aboard the guided missile frigate USS Underwood (FFG 36) during Silent Forces Exercise May 30, 2012, in the Pacific Ocean. SIFOREX is a biennial, bilateral naval exercise that provides the opportunity for U.S. and Peruvian surface and air forces to work with the Peruvian navy's diesel submarine fleet. SIFOREX is part of Southern Seas, a U.S. Southern Command-directed operation designed to strengthen relationships with regional partner nations and improve operational readiness for all assigned units. (U.S. Navy photo by Mass Communication Specialist 2nd Class Stuart Phillips/Released)