LOS ANGELES - Port Security Unit 311, 312 and 313 members finishing assembling a shelter system at San Clemente Island during Exercise Patriot Hook. During Patriot Hook, an exercise simulating a joint force response to a natural disaster, PSU members successfully tested their ability to mobilize within 96 hours and establish sustained operations within 24 hours. U.S. Coast Guard photo by Petty Officer 2nd Class Michael Anderson.