Figure 7-8. OCCUPATION OF THE ORP 7-21. PATROL BASE. A patrol base is a security perimeter that is set up when a squad or platoon conducting a patrol halts for an extended period. Patrol bases should not be occupied for more than a 24 hour period (except in emergency). A patrol never uses the same patrol base twice. a. Use. Patrol bases are typically used • To avoid detection by eliminating movement. • To hide a unit during a long detailed reconnaissance. • To perform maintenance on weapons, equipment, eat and rest. • To plan and issue orders. • To reorganize after infiltrating on an enemy area. • To establish a base from which to execute several consecutive or concurrent operations. b. Site Selection. The leader selects the tentative site from a map or by aerial reconnaissance. The site’s suitability must be confirmed and secured before the unit moves into it. Plans to establish a patrol base must include selecting an alternate patrol base site. The alternate site is used if the first site is unsuitable or if the patrol must unexpectedly evacuate the first patrol base. c. Planning Considerations. Leaders planning for a patrol base must consider the mission and passive and active security measures. A patrol base (PB) must be located so it allows the unit to accomplish its mission. • Observation posts and communication with observation posts. • Patrol or platoon fire plan. • Alert plan. • Withdrawal plan from the patrol base to include withdrawal routes and a rally point, rendezvous point, or alternate patrol base. • A security system to make sure that specific Rangers are awake at all times.