The echoMAP CHIRP 42cv is one of the discontinued Garmin fish finders. It’s a CHIRP sonar unit with ClearVü sonar, GPS, and preloaded with the Worldwide Basemaps. For reference, this is the Garmin part number 010-01812-02, the one that includes the GT20 transducer.
Key Features and Specifications
- Display: 4.3″ diagonal, 272H x 480V pixel resolution, WQVGA color, backlit
- Sonar: CHIRP 2D, CHIRP ClearVü
- Frequency and Coverage:
Standard: 200 kHz / 15° and 77 kHz / 45°
ClearVü: 455 kHz / 2.5° (fore to aft) x 53°, 800 kHz / 1.6° (fore to aft) x 29°
- Depth Capability:
Standard: 1,900 (579 m)
ClearVü: 750 ft (228.6 m)
- Transducer: GT20-TM (4-pin), for HD-ID and ClearVü
- Power Output: 500 Watts (RMS)
- GPS: 5Hz, Internal
- Maps: Worldwide Basemap
- Routes, Waypoints, Tracks: 100; 5,000; 50,000 points (50 saved tracks).
Sonar and transducer
The echoMAP CHIRP 42cv is capable of three frequencies for 2D sonar 50/77/200 kHz, and three frequencies for ClearVü 260/455/800 kHz. However, the transducer supplied with the unit is the GT20-TM (4-pin), and it’s only capable of 77/200 kHz for 2D, and 455/800 kHz for ClearVü. This transducer has a built-in temperature probe, comes with a transom mount, and has 20′ (6 m) of cable.
This Garmin combo can actually use CHIRP for both types of sonar, 2D and ClearVü. This means it can provide clearer images, a better target separation, and superior depth penetration. Images will appear with less clutter, and for example, if the transducer beam hits a group of fish that are close together, it’s a higher chance that they’ll appear on screen as several arches, rather than a big dot of color.
Evidently, it can use its CHIRP modes with the supplied transducer. With this transducer, the unit can use two frequencies for 2D, 77/200 kHz. In other words, it’s capable of using Mid CHIRP and High CHIRP. However, it’s capable of 50 kHz frequencies and Low CHIRP, but in order to use this mode, you’ll need a 50/200 kHz transducer. The sonar pulse modulation is not specified for Mid and High CHIRP, but evidently, it’s somewhere around 77 and 200 kHz.
For ClearVü, the supplied transducer covers the 455/800 kHz frequencies, with a CHIRP modulation between 435-475 kHz and 800-840 kHz. ClearVü is a sonar technology great for observing and understanding structure. It offers photo-like clarity imaging, and it’s great if you’re looking for sunken objects or simple for places where fish might hide.
For the 2D traditional sonar, the unit uses two conical beams, with an angle of 45° for 77 kHz, and 15° for 200 kHz. For ClearVü, the beams used are very thin fore-to-aft, but wider side to side. For 455 kHz, it uses a 2.5° / 53° beam, while for 800 kHz the beam is narrower and thinner, of 1.6° / 29°. This unit is also dual-frequency capable. This means it can use both its 77/200 kHz beams simultaneously, and you can view the returns in split-screen.
The system’s maximum depth capability is 2,300 ft (701 m). However, with the supplied transducer, its maximum depth capability is 1,900 ft (579 m) for traditional mode and 750 ft (228 m) in ClearVü. When it comes to vessel speed, this unit should be able to maintain a bottom reading at speeds up to 30 MPH. However, for a clear picture, it’s recommended to sail at speeds up to 6 MPH.
Among other sonar related functions, we can count A-Scope, Depth Alarm, Bottom Lock, and Sonar Recording.
Navigation and charts
To begin with, this unit comes with the Worldwide Basemaps for navigation reference. These are generic charts, without too much detail, but still, they should provide enough information regarding boundaries, shores, bodies of water etc. However, the good news is this unit is compatible with various other more inclusive chart bundles, such as LakeVü, LakeVü HD Ultra, BlueChart g2 HD, or BlueChart g2 Vision HD.
One of the best features of this unit is QuickDraw Contours. This function allows you to generate the depth contours of a body of water, using sonar information and the unit’s base maps. Differently put, no matter what charts you’re using with your unit, and whether or not your favorite lake is covered by them, you can always use it to determine the latest depth contours. You can also share your maps with the Quickdraw Community on Garmin Connect.
The unit can save up to 5,000 waypoints, and 100 routes. It also has a trail recording function, allowing you to save 50,000 track points and up to 50 tracks. Evidently, you can convert tracks into routes, add waypoints to them and retrace them.
Needless to say, the Garmin echoMAP CHIRP 42cv features a fast and accurate 5 Hz GPS system and GLONASS, refreshing your position up to 5 times per second. Via GPS the unit also measures the speed of your boat, indicating it on screen.
Control unit features
This Garmin unit is IPX7 waterproof, which means it’s built to withstand water splashes or rain without any problem. It features a small display, with a 4.3″ diagonal and 480V x 272H pixel resolution. The display is WQVGA color, and also features LED backlight, which means it offers excellent readability in direct sunlight or during night time.
It’s an NMEA 0183 capable unit, also integrating a microSD card slot, for data transfer, sonar recording, or chart upgrades.
Finally, the unit does not come with a cover, but the box does include the classic, tilt-and-swivel mount.
- Fast and accurate internal GPS;
- Preloaded with the Worldwide Basemaps;
- Compatible with various other charts, such as BlueChart g2 Vision or LakeVü HD Ultra;
- Quickdraw Contours;
- Tide tables information;
- CHIRP technology offering superior clarity, target separation and target definition, for both 2D and ClearVü;
- Dual-frequency sonar;
- Transducer (GT20-TM, 4-pin) included;
- Data graphs and other sonar functions;
- Sonar recording and sonar history rewind;
- Supports AIS and DSC-capable VHF radio;
- Quick disconnection (tilt-swivel) and flush mount included;
- NMEA 0183 port;
- Easy to install;
- Straightforward, comprehensive operation.
- Manual may not be specific to the unit, but for the whole series of units, and some of the instructions may not apply to this one;
- No unit cover.
The Garmin echoMAP CHIRP 42cv is a small, but inclusive unit, offering dual-frequency 2D sonar, ClearVü imaging sonar, also using CHIRP technology for both types of sonar, for a better target separation and overall, crisper images. It’s a unit with GPS and comes with the Worldwide Basemaps. It’s great for both fresh and saltwater. Since it’s a small unit, it might not be the best choice for a bigger vessel, but it’s perfect for small boats, kayaks, canoes etc. It’s not one of the most affordable unit, but considering the whole amount of features that it offers, and the fact that it comes with a transducer which costs more than $100, it’s safe to say the whole system stands up to its price.