Raymarine ACU-400 Actuator Control Unit

The Raymarine ACU-400 Actuator Control Unit is the command center for modern hydraulic autopilot systems, engineered for cruising sailboats and power vessels that demand precision helm control. Built to interface seamlessly with Raymarine's Evolution autopilot architecture, the ACU-400 manages the hydraulic pressure and flow that powers your vessel's steering actuator—giving you true hands-free navigation in all conditions. Whether you're running a full watch or threading through crowded anchorages, this control unit is the brain behind repeatable, reliable steering.

At its core, the ACU-400 regulates hydraulic actuation through closed-loop feedback and proportional valve control, maintaining course with minimal deviation even in beam seas or following swells. The unit weighs a compact 5 pounds and mounts cleanly in engine spaces or aft compartments, communicating with your autopilot display and rudder feedback sensor via established Raymarine network protocols. Its robust design handles the sustained pressure cycles demanded by full-displacement cruising yachts, translating digital helm commands into smooth, linear rudder movement without hunting or over-correction.

The Raymarine ACU-400 is ideal for owners upgrading older mechanical autopilot systems or installing Evolution-series electronics on newly acquired vessels. Compatibility depends on having a hydraulic steering plant, a matching Raymarine autopilot course computer (such as EV-100, EV-200, or integrated multifunction display), and a functional rudder feedback transducer. Installation typically requires routing hydraulic hoses from the steering pump and helm cylinder to the ACU-400, then wiring the control and sensor harnesses—a task best handled by a qualified marine electrician familiar with your vessel's systems. Proper commissioning ensures your autopilot delivers the rock-solid course control that separates tired crews from well-rested ones on passage.