Simrad IS44 Heavy Duty Autopilot with Virtual Feedback Includes IS44 Control Head, NAC-3 Processor, and Precision 9 Compass The NAC-3 Autopilot Computer is the brains behind your autopilot system. NAC-3 contains the control algorithms developed to helm a yacht across a broad range of weather conditions and sea-states, alongside the electronics needed to operate a hydraulic or mechanical drive unit, while also interfacing with other components including heading sensors and rudder feedback units. The NAC-3 was designed for boats 10 metres (33 feet) or greater in length and is rated to operate high-current hydraulic drives, mechanical drive units, and solenoid valves with a current rating of 30 Amps continuous (50 Amps peak).