Garmin Echomap Plus 42cv + GT20-TM

Combo Chartplotter with CHIRP and ClearVü for Fishing and Coastal Navigation

The Garmin ECHOMAP Plus 42cv with GT20-TM transducer is a compact chartplotter fishfinder that combines traditional CHIRP sonar and CHIRP ClearVü scanning technology in a single unit, delivering high-resolution underwater imagery ideal for sport fishing, coastal navigation and use on small boats. The 4.3" color display with anti-glare treatment ensures clear readability even in direct sunlight, while the integrated physical keypad simplifies on-board operation.

CHIRP Sonar Technology: Superior Target Separation and Image Clarity

Unlike conventional fishfinders that transmit a single frequency at a time, CHIRP (Compressed High-Intensity Radar Pulse) technology simultaneously sends a continuous spectrum of frequencies — from low to high — and interprets the returning echo of each individual frequency. This approach provides the sonar with significantly more information, producing sharper, higher-resolution images with improved target separation — essential for accurately identifying fish and underwater structures.

CHIRP ClearVü: Near-Photographic View of What's Below

The GT20-TM transducer also integrates CHIRP ClearVü scanning sonar, which delivers superior resolution for more accurate target discrimination and a greater level of detail. The resulting images clearly show bottom structure, wrecks, vegetation and schools of fish directly beneath the hull, with a visual quality approaching that of a photograph.

Quickdraw Contours: Custom HD Depth Maps Created On the Go

The built-in Quickdraw Contours feature automatically generates HD bathymetric maps with 1-foot contour lines as you fish — no subscription or external service required. Depth contours are drawn in real time on the display and are immediately available for use. Maps you create can be kept private or shared with the Quickdraw Community on Garmin Connect™. Waypoints and routes can also be shared with other compatible units in the ECHOMAP and STRIKER series.

BlueChart g3 Charts and Premium Map Compatibility

The unit comes preloaded with a worldwide basemap and is compatible with BlueChart® g3 and BlueChart® g3 Vision coastal charts featuring integrated Navionics® data. The Vision version supports advanced features including high-resolution satellite imagery, perspective and 3D views above and below water, aerial photos of harbors, bays and marinas, and Auto Guidance technology, which automatically calculates the optimal route based on chart depth data and known hazards.

5 Hz Internal GPS and Quick-Release Mount

The built-in 5 Hz GPS receiver updates position and heading five times per second, providing a precise and responsive navigation track even at higher speeds. The new quick-release mount with integrated power and data cable allows the unit to be installed and removed in seconds. Both transom and trolling motor mounting brackets are included in the box.

Technical Specifications

In the Box

• ECHOMAP Plus 42cv
• GT20-TM transducer
• Power/data cable
• Quick-release mount
• Installation hardware
• Documentation