Machinist's mates operate and maintain steam turbines and reduction gears used for ship propulsion and auxiliary machinery such as turbogenerators, pumps and oil purifiers. They also maintain auxiliary machinery outside of main machinery spaces, such as electrohydraulic steering engines and elevators, refrigeration plants, air conditioning systems and desalinization plants. They may also operate and maintain compressed gas producing plants.

ETs are responsible for electronic equipment used to send and receive messages, detect enemy planes and ships, and determine target distance. They must maintain, repair, calibrate, tune, and adjust all electronic equipment used for communications, detection and tracking, recognition and identification, navigation, and electronic countermeasures.

Fire Controlmen (FC) provide weapon direction systems employment recommendations; perform organizational and intermediate maintenance on digital computer equipment, subsystems, and systems; operate and maintain combat and weapons direction systems, surface-to-air and surfaceto-surface missile systems, and gun fire control systems at the organizational and intermediate level; inspect, test, align, and repair micro/minicomputers and associated peripheral equipment, data conversion units, data display equipment, data link terminal equipment, print devices, and system related equipment; perform analyses for detailed systems, computer programs, electronics, and electronic casualty control; and operate associated built-in and external test equipment; load, initialize, and run preprogrammed diagnostics, performance and testing routines for digital computer equipment, digital systems, digital subsystems, and overall combat systems.