The GMI 40 is a dedicated instrument display, not a chartplotter. It displays real-time speed, depth, wind, heading, engine and fuel data from compatible devices elsewhere on the boat, rather than replacing the sensors that produce it.
Network architecture
The GMI 40 integrates with compatible onboard equipment through NMEA 2000, the industry standard, and Garmin’s own proprietary BlueNet network. Wireless connections are limited to gWind wireless sensors, marine remotes and compatible quatix smartwatches. Software updates run through the free ActiveCaptain smartphone app.
Display and build
The touchscreen measures 4.3 inches on the diagonal, with 800 x 480 resolution on a WVGA IPS panel and edge-to-edge glass. The housing is IPX7 rated, measures 115 x 91 x 30mm and weighs 240g. Garmin has styled it to match its GPSMAP chartplotters.
The GMI 20 retrofit path
Owners running the earlier GMI 20 can upgrade without cutting a new hole in the dash, using a separate adapter plate that fits the existing cutout. The adapter plate is sold separately, so its cost needs to be included when comparing the upgrade.
For pricing see https://www.garmin.com/en-NZ/p/1849621/











