Sailors on the flight deck of the aircraft carrier USS Ronald Reagan stand by as an SH-60F Seahawk assigned to the Black Knights Helicopter Anti-Submarine Squadron 4 delivers cargo during a vertical replenishment. The Seahawk is a twin-engine helicopter used for anti-submarine warfare, search and rescue, drug interdiction, anti-ship warfare, cargo lift, and special operations. HS-4 is embarked aboard Ronald Reagan completing a Composite Training Unit Exercise in preparation for an upcoming deployment.