Overview

The Simrad 000-13901-001 is an A2004 autopilot system kit with an HS75 GNSS compass, supplied as a no-drive package for boats that already have, or plan to add, a compatible steering drive unit.

At the helm, the A2004 controller uses a 4.1-inch optically bonded color LCD with a 170 degree viewing angle, plus a rotary dial and dedicated mode keys for quick course changes and steering mode access. The controller is rated IPX7 for spray and washdowns, and it is specified to operate from -25 to +65 C.

The AC70 course computer handles steering control and system logic, while the RF300 rudder feedback unit provides rudder angle for consistent response. The HS75 adds GNSS-based heading with up to 10 Hz updates and heading accuracy specified to 0.75 degrees, so the autopilot can hold a steady course at low speed and even when the boat is stationary.

Key features

• No-drive system kit: controller, course computer, rudder feedback, and HS75 heading sensor are included; a hydraulic pump or other drive unit is not.
• A2004 helm controller with a 4.1-inch optically bonded color display, 320 x 240 resolution, and a 170 degree viewing angle.
• Rotary dial with an anodized aluminum knob and dedicated keys for steering modes, a configurable WORK mode, and turn patterns.
• No Drift steering mode to compensate for wind and tide and keep the vessel on heading.
• NMEA 2000 certified networking, with NMEA 0183 in/out available for integrating with other onboard systems.
• AC70 course computer supports 12 V or 24 V DC supply for common commercial electrical systems.
• Optional single-thruster control when an AD80 or SD80 interface module is added.
• HS75 GNSS compass supports GPS, GLONASS, BeiDou, Galileo, and QZSS for global coverage.

What's included

• A2004 autopilot controller (helm display and rotary control head)
• AC70 autopilot computer (course computer)
• RF300 rudder feedback unit
• HS75 GNSS compass
• NMEA 2000 cable (15 ft)

Installation and setup

The A2004 controller can be bracket mounted or flush mounted at the helm. The unit measures 177 mm wide by 115 mm high and is about 56 mm deep; with the bracket installed, allow up to 204.8 mm width and 124.5 mm height for clearance.

Mount the AC70 course computer in a dry, protected space where you can access steering drive wiring and the rudder feedback connection. Leave service loops on cabling and protect all penetrations and connectors from chafe and moisture.

Compatibility and fit

This kit is aimed at non-IMO professional vessels and similar boats that want the A2004 style of controller and steering logic. Because it is supplied without a drive, you will still need a compatible drive unit for your steering system, such as a reversible hydraulic pump or non-isolated solenoid valve control, matched to your cylinder size and steering layout.

Rudder feedback is included, so the system fits installations where you can mount a feedback arm at the rudder stock or steering linkage. For low-speed maneuvering with thruster assistance, the system supports a single thruster when paired with an AD80 or SD80 interface module.

Electrical and network integration

The A2004 controller and HS75 compass connect to an NMEA 2000 backbone using Micro-C connections, so plan for a properly powered backbone with terminators and an available tee for each device. The controller can be powered from the NMEA 2000 network, while the AC70 course computer uses a dedicated 12 V or 24 V DC supply.

For navigation steering, the autopilot can take route and guidance data from compatible onboard navigation equipment over the network. Mount the HS75 where it has a clear view of the sky and a stable platform to get the most consistent heading performance.

Use on board

This setup is a strong fit for workboats, commercial fishing vessels, and passenger boats where the helmsman wants a rotary interface that is quick to operate in rough conditions. It also fits refits replacing older professional autopilots, especially when adding GNSS heading to improve course keeping in wind and tide.

Maintenance and care

After heavy weather or washdowns, rinse salt residue from the helm controller and wipe the screen with a soft, damp cloth. Periodically check NMEA 2000 connectors, the rudder feedback linkage, and the course computer wiring for looseness or corrosion, especially in high-vibration installations.