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Upgrade your boating experience with the Garmin GT21-TM transom mount transducer, a powerhouse for serious anglers chasing fish in coastal waters or pushing offshore. This versatile unit combines high-performance traditional sonar with advanced ClearVü CHIRP scanning technology, delivering razor-sharp images of fish arches, bottom structure, and underwater terrain. Whether you're targeting trophy bass in shallow bays or scanning deep reefs for snapper, it paints a vivid picture beneath your hull, helping you locate and land more fish with confidence.
Built tough for real-world marine conditions, the GT21-TM mounts easily on your transom and integrates seamlessly with compatible Garmin chartplotters and fishfinders. Its fast-response temperature sensor keeps you informed on water conditions, letting you adjust tactics on the fly as surface temps shift with tides or weather.
| Category | Traditional Sonar | ClearVü CHIRP |
|---|---|---|
| Frequency | 50/200 kHz | 260 kHz (245-275 kHz) & 455 kHz (445-465 kHz) |
| Power | 600 W | 500 W |
| Beamwidth | 40°/10° | 2.0° x 51° @ 260 kHz / 1.4° x 29° @ 455 kHz |
| Max Depth | 1,500 ft | 1,000 ft |
| General Specs | Details |
|---|---|
| Sensors | Depth & Temperature |
| Pin Count | 8-pin |
| Cable Length | 30 ft |
| Transom Angle | 0° to 70° |
In the heat of a tournament or during a family fishing trip, clarity is king. Traditional sonar excels at marking schools of baitfish and gamefish with crisp arches, while ClearVü reveals hidden wrecks, drop-offs, and brush piles like a downward-facing spotlight. This combo reduces guesswork—spot a thermocline, track bait balls, or pinpoint that submerged log where lunkers lurk.
Perfect for bass boats, center consoles, and offshore rigs. Users report fewer missed strikes thanks to superior separation, even in murky water or heavy cover. The built-in temp sensor helps dial in lure choices, as species migrate with subtle changes.
Mounting is straightforward on most hulls: Clean the transom, select a spot 1/3 from the keel to stern, and secure with included hardware. Angle the transducer parallel to the waterline at speed for optimal performance—test at planing speeds and adjust brackets as needed.
Regular maintenance like wiping salt residue and checking mounts keeps it performing like new season after season.
ClearVü provides high-resolution, photo-like images directly below and beside your boat, revealing structure details that traditional sonar marks as arches. Together, they offer complete coverage for spotting fish and bottom contours.
Yes, its transom mount design maintains bottom lock at planing speeds when properly adjusted, making it great for tournament bass boats or offshore runs up to 70 MPH.
It connects via 8-pin to most Garmin marine chartplotters like GPSMAP, ECHOMAP UHD, and STRIKER series that support ClearVü and traditional CHIRP sonar.
Traditional sonar reaches 1,500 feet for deep-water species; ClearVü scans to 1,000 feet, sufficient for most structure fishing in oceans or large lakes.
Absolutely—a built-in fast-response sensor provides accurate surface water temp readings, crucial for locating active fish zones.
Most users do, with no hull drilling required. Follow the guide for bracket placement to ensure clear water flow and avoid cavitation.
The wide 40° beam at 50 kHz covers large areas for offshore bait balls, while narrower beams provide precision for individual targets.
Garmin make products that are engineered on the inside for life on the outside. We bring GPS navigation and wearable technology to the automotive, aviation, marine, outdoor and fitness markets. We believe every day is an opportunity to innovate and a chance to beat yesterday. We offer products with essential utility, leading-edge technologies, compelling features, and exceptional ease-of-use to create clear differentiators our customers appreciate and desire.
GT21-TM Transom Mount Transducer, Traditional 600W, 50/200kHz, ClearVü CHIRP 500W, 260 & 455kHz
Perfect for coastal and offshore fishermen who want traditional sonar and CHIRP ClearVü scanning sonar. This transom mount transducer consistently displays clear and crisp fish arches with superior target separation as well as clear definition of structure below the boat.
The CHIRP ClearVü element has a power rating of 500W and operating frequencies of 260/455 kHz. The traditional sonar has a power rating of 600 W and operating frequencies of 50/200 kHz. It also includes a built-in fast response temperature sensor.
GT21-TM includes an 8-pin transducer with mounting hardware and installation instructions. Follow the instructions carefully to avoid damaging your boat.
Ships within 48 hours · Estimated delivery Aug 7 - Aug 12
US$40
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