Overview

The Garmin Reactor 40 Steer-By-Wire Corepack is a below-deck autopilot corepack built to interface with Yamaha Helm Master steer-by-wire steering and run heading control from a compatible Garmin display. The solid-state 9-axis AHRS course computer (CCU) is 91.4 mm in diameter, IPX7-rated, and specified for -15°C to 55°C. The CCU ties into your NMEA 2000 backbone and is powered from the network at 9 to 16 VDC (LEN 3, 150 mA).

This package is intended for boats equipped with Yamaha Helm Master and is not compatible with Yamaha Helm Master EX. Helm control depends on configuration: it can be supplied with a GHC autopilot instrument, or set up without an instrument for boats that already have a compatible helm control option.

Key features

• Interfaces with Yamaha Helm Master steer-by-wire via the included Yamaha gateway (not compatible with Yamaha Helm Master EX).
• Solid-state 9-axis AHRS supports flexible CCU mounting orientation to fit typical below-deck spaces.
• CCU is rated IPX7 and specified for -15°C to 55°C; 91.4 mm diameter footprint helps when planning mounting space.
• NMEA 2000 integration with CCU power input of 9 to 16 VDC (LEN 3, 150 mA) for network planning and load checks.
• Buzzer/alarm module included (23 mm by 25 mm) with a 3.0 m cable for audible alerts.
• Core NMEA 2000 cabling and network pieces are included: 2 m drop cables, power cable, T-connectors, and terminators.
• Works with a compatible Garmin networked chartplotter for control, setup, and on-water adjustments.

Variants

This corepack is offered with different autopilot instrument options, depending on how you want to run helm control.

The steering integration hardware remains consistent, while the configuration changes based on which GHC autopilot instrument is included, or whether no instrument is included.

• 010-02794-04: Autopilot instrument included: GHC 50. A 5 in WVGA touchscreen (800 x 480) with an IPX7 rating, plus flat or flush mounting options for common helm layouts.
• 010-00705-87: Autopilot instrument included: GHC 20. A 4 in diagonal color display (320 x 240) with NMEA 2000 and NMEA 0183 connections for helm control and integration.
• 010-00705-91: Autopilot instrument: none included. Intended for systems where helm control is handled by an existing compatible Garmin display or a separate autopilot instrument already on board.

What’s included

• Reactor 40 CCU (Course Computer Unit)
• Yamaha gateway
• CCU cable (3.0 m)
• Buzzer/alarm (3.0 m cable)
• NMEA 2000 drop cables (2 m)
• NMEA 2000 power cable
• NMEA 2000 T-connectors
• Male and female terminators
• Autopilot instrument (varies by configuration)
• Documentation

Compatibility and fit

Plan this corepack for boats with Yamaha Helm Master steer-by-wire steering and a compatible Garmin networked chartplotter for autopilot control. The CCU connects on NMEA 2000, and the backbone needs to be powered within the NMEA 2000 range (9 to 16 VDC). For boats that run a 24 V house system, the usual approach is powering the NMEA 2000 backbone through a proper converter so the network stays within spec.

For space planning behind the dash and under the console, the gateway module is 130 mm by 60 mm by 25 mm, and the buzzer is 23 mm by 25 mm. The CCU is a compact round module at 91.4 mm diameter, which helps when fitting it near bulkheads and inside consoles.

Installation and setup

Mount the CCU in a dry location below decks where it is protected from direct spray and away from strong magnetic sources. The solid-state sensor package allows flexible mounting orientation, which helps when you are working around rigging tubes and existing helm plumbing. Route the CCU and buzzer cables cleanly to reduce chafe, and keep service loops so connectors are accessible for troubleshooting.

Once wired into the NMEA 2000 backbone and connected through the Yamaha gateway, setup includes commissioning and calibration. Expect to run the on-water steps from your helm control option so heading and steering response match your hull and typical load.

Use on board

This is a good match for Yamaha Helm Master boats that spend time on longer transits, offshore runs, or trolling, where holding a steady heading takes load off the helmsman. It supports common autopilot functions such as heading hold and step turns, and sailing-related functions like wind hold and tack or jibe are available when compatible wind data is present on the system.

Maintenance and care

After installation, the main routine work is checking cable routing, strain relief, and connector condition during seasonal inspections. Keep NMEA 2000 connections clean and dry, and make sure the buzzer remains audible from the helm after any dash refits or sound insulation work.