200604-N-NT795-027 SAN DIEGO (June 4, 2020) Chief Boatswain�s Mate Luis Montealegre, assigned to Coastal Riverine Group (CRG) 1, strips oil samples as part of pre-operational checks during a Mark VI Patrol Boat Operators Course. The Coastal Riverine Force is a core Navy capability that provides port and harbor security, high value asset security, and maritime security in the coastal and inland waterways. (U.S. Navy photo by Chief Boatswain�s Mate Nelson Doromal/Released)