Overview

The Garmin GCV 20 is an Ultra High-Definition scanning sonar black box that adds ClearVü and SideVü views to a compatible chartplotter over the Garmin Marine Network. It runs on 10 to 35 Vdc (works on 12 V and 24 V systems) and transmits at 500 W RMS.

The module measures 192 x 251 x 66 mm (7.6 x 9.9 x 2.6 in.) and uses a fully gasketed polycarbonate case with an IPX7 water rating. It is meant to be mounted where it cannot be submerged, with ventilation around the unit, and at least 260 mm (10.2 in.) from a magnetic compass.

Key features

• Outputs sonar data to compatible chartplotters over the Garmin Marine Network
• Supported CHIRP frequencies: 260, 455, 820, and 1120 kHz for ClearVü and SideVü scanning
• 500 W RMS transmit power for Ultra High-Definition scanning performance
• Power input from 10 to 35 Vdc with 10.5 W maximum power usage
• Uses a 4.0 A fast-acting mini blade fuse in the in-line fuse holder
• IPX7 water rating with a fully gasketed polycarbonate housing
• Three Garmin Marine Network ports for tying into a networked helm setup

Variants

This sonar module is offered in two configurations based on whether a transducer is included in the box.

Both options use the same networked black box approach: connect the module to the Garmin Marine Network, provide fused DC power, then connect a GT34UHD-series scanning transducer to generate Ultra High-Definition ClearVü and SideVü images.

• 010-02055-10: Includes transducer No. This configuration supplies the black box sonar module and is used when a compatible GT34UHD transducer is being sourced separately.
• 010-02055-00: Includes transducer Yes. This configuration includes a GT34UHD-TM transom-mount transducer, with mounts to support common transom installs and trolling motor installs.

Compatibility and fit

The GCV 20 is meant for boats that already have, or are being rigged with, a compatible chartplotter on the Garmin Marine Network. Plan cable runs for DC power, the marine network connection (either to a network expander or directly to a chartplotter network port), and the transducer cable to the mounting location.

Ultra High-Definition scanning is done with GT34UHD transducer models (transom-mount, thru-hull, or paired thru-hull). Hull type, deadrise, and mounting hardware requirements are driven by the transducer selection and installation style, not by the black box module.

Installation and setup

Mount the module in a dry, ventilated compartment where the status LEDs can be seen and the connectors are easy to reach. Avoid forcing connectors into ports; align the connector notch, press the connector fully into place, then hand-tighten the locking ring so it stays secure under vibration.

For power, connect to a fused 10 to 35 Vdc supply and keep the in-line fuse holder in place with a 4.0 A fast-acting mini blade fuse. When fastening into fiberglass, a small countersink through the gelcoat helps reduce the chance of cracking, and an anti-seize lubricant on stainless screws can prevent binding during installation.

On-the-water use

The supported CHIRP frequency set (260, 455, 820, and 1120 kHz) lets you balance detail and range based on conditions and how you are using the boat. Maximum depth and side range depend on the transducer, bottom type, and water conditions, with the higher frequencies typically used when you want more definition at shorter ranges.

This setup fits boats that spend time fishing structure, reefs, and channel edges, and it also works well for coastal cruising where having clearer bottom detail helps when you are learning new water.

Maintenance and care

The IPX7 rating covers incidental water exposure, but the unit should not be mounted where it can be submerged. After salty runs or washdowns, rinse the area as needed and periodically check that locking rings are snug and cables are supported to prevent chafe.