Overview

The Garmin Reactor 40 Steer-By-Wire Corepack is an autopilot package intended for Viking yachts running the VIPER steer-by-wire steering system, with helm control handled through a compatible Garmin chartplotter and/or a GHC autopilot instrument (depending on the configuration). The core sensor module (CCU) is 91.4 mm in diameter, weighs 5.6 oz (159 g), and is waterproof to IPX7, which suits a below-decks mounting location.

The CCU uses a solid-state 9-axis AHRS and connects on NMEA 2000. NMEA 2000 power input is 9 to 16 V, and the CCU has a NMEA 2000 LEN of 3 (150 mA), which helps when you are planning network power and loads.

Key features

• Built for Viking VIPER steer-by-wire steering systems (not a hydraulic pump kit)
• Solid-state 9-axis AHRS lets the CCU be mounted in almost any orientation and still calibrate properly
• CCU housing is IPX7-rated for wet bilges and washdown-prone compartments
• NMEA 2000 integration for autopilot data sharing and control on the boat network
• NMEA 2000 bus power input of 9 to 16 V; CCU NMEA 2000 LEN 3 (150 mA) for power budgeting
• CCU operating temperature range: -15°C to 55°C (5°F to 131°F)
• Includes an audible buzzer/alarm for autopilot alerts
• Supports onboard control from compatible Garmin devices, including the Reactor autopilot remote and select quatix marine smartwatches when paired with a compatible Garmin chartplotter or GHC 50

Variants

This corepack is offered in multiple configurations so the helm control setup can match what is already installed at your station.

The difference between these part numbers is the included autopilot instrument: GHC 50, GHC 20, or no dedicated autopilot instrument in the box.

• 010-02794-05: Autopilot instrument included: GHC 50. This adds a 5-inch touchscreen autopilot display at the helm for direct control and status without relying on the MFD screen.
• 010-00705-88: Autopilot instrument included: GHC 20. This adds a 4-inch color helm control display that keeps core autopilot functions available on a dedicated screen.
• 010-00705-92: Autopilot instrument not included. Helm control is handled through a compatible Garmin chartplotter on the network, with a dedicated GHC display optional separately.

What’s included

• Reactor 40 CCU (Course Computer Unit)
• CCU cable
• Buzzer
• NMEA 2000 drop cables (2 meters)
• NMEA 2000 power cable
• NMEA 2000 T-connectors
• Male and female terminators
• Documentation

Compatibility and fit

This package is specific to Viking VIPER steer-by-wire steering. If the boat is hydraulic, mechanical cable, or another electronic steering platform, the correct Reactor 40 corepack and steering interface are different.

Plan for helm control up front. If you want a dedicated autopilot screen at the helm, choose a variant that includes a GHC instrument. If you prefer to run autopilot control through an existing compatible Garmin chartplotter, the variant without a GHC instrument keeps the helm hardware simpler.

Installation and setup

The CCU is typically mounted below decks, away from strong magnetic sources and heavy-current wiring. Because the 9-axis AHRS supports flexible orientation, you can usually find a practical location in a dry, accessible space such as under a helm, inside a console, or in a protected machinery-adjacent compartment.

NMEA 2000 cabling and terminators are included for tying into an existing backbone or starting a small segment. After installation, commissioning and calibration are part of bringing any autopilot online, and it is normally done during a sea trial so the unit can learn the boat’s handling.

On-board use

When tied into a compatible Garmin chartplotter, Reactor 40 corepacks support common powerboat and sailing autopilot functions such as heading hold and step turns. Sailing features like wind hold and tack or jibe become available when paired with a wind sensor.

This setup is a good match for Viking owners who do long coastal runs, offshore legs, or trolling days where hands-on steering fatigue adds up, and who want the boat’s VIPER system to be the steering interface rather than adding pumps or extra hydraulics.