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Jam nut
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Thread isolator
Hull isolator
Documentation
Do you have an old GPS unit lying around? The GPS Nation Trade In and Up program is a great way to trade in your old and used GPS for credit towards a new GPS. The choice is entirely yours! We’ve made the process simple and streamlined. Follow these simple steps, and you will be on your way to receiving credit towards your brand new GPS!
1. Get a quote
To get your free quote, provide your GPS type, manufacturer, model, and condition. Within 24 hours, you will receive a quote for the trade-in value of your current product. The GPS trade-in/trade-up form is at the bottom of this page.
2. Ship your product(s) for trade
After accepting our offer, pack your product(s) safely and ship them to us using the pre-paid shipping label provided to you. We will provide a confirmation email when your trade-in arrives at our warehouse. You have 30 days from the date you complete your on-line trade to ship the product to GPS Nation.
3. Make your purchase
Once we receive your product at our warehouse and we validate the stated condition, we will send you a confirmation email. If you elect to receive credit towards a new GPS at gpsnation.com, your store credit will be issued, and you are free to make your purchase.
Manual & Warranty
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Ask a Question
Tech Specs
In The Box
Jam nut
Washer
Thread isolator
Hull isolator
Documentation
Trade-In
Do you have an old GPS unit lying around? The GPS Nation Trade In and Up program is a great way to trade in your old and used GPS for credit towards a new GPS. The choice is entirely yours! We’ve made the process simple and streamlined. Follow these simple steps, and you will be on your way to receiving credit towards your brand new GPS!
1. Get a quote
To get your free quote, provide your GPS type, manufacturer, model, and condition. Within 24 hours, you will receive a quote for the trade-in value of your current product. The GPS trade-in/trade-up form is at the bottom of this page.
2. Ship your product(s) for trade
After accepting our offer, pack your product(s) safely and ship them to us using the pre-paid shipping label provided to you. We will provide a confirmation email when your trade-in arrives at our warehouse. You have 30 days from the date you complete your on-line trade to ship the product to GPS Nation.
3. Make your purchase
Once we receive your product at our warehouse and we validate the stated condition, we will send you a confirmation email. If you elect to receive credit towards a new GPS at gpsnation.com, your store credit will be issued, and you are free to make your purchase.
Manual & Warranty
Overview
Garmin GT15M-THF 20° Stainless Steel Thru-Hull CHIRP Transducer (010-02868-02)
Introduction
The Garmin GT15M-THF 20° thru-hull CHIRP transducer delivers dependable midband sonar performance for vessels with steep hull deadrise angles between 16° and 24°. Built for anglers and boaters who demand reliable underwater imaging without fairing blocks or excessive hull drag, this stainless steel transducer features an internally tilted 20° element that maintains proper beam alignment while sitting flush against your hull. Operating at 600 watts across a 85–165 kHz CHIRP frequency band, it generates crisp fish arches, accurate bottom contours, and detailed structure imaging in both freshwater and saltwater environments.
Key Features
- 600-watt midband CHIRP sonar output with 85–165 kHz frequency range
- Maximum depth capability of 1,900 feet in freshwater and 1,200 feet in saltwater
- 20° internally tilted design eliminates need for fairing blocks on hulls with 16°–24° deadrise
- Durable stainless steel thru-hull housing with flush-mounted profile to reduce drag
- Integrated fast-response water temperature sensor for real-time fishing condition monitoring
- Garmin Auto-ID technology for automatic transducer recognition and plug-and-play configuration on compatible chartplotters
Data Insights
The GT15M-THF's 600-watt CHIRP transmission across its midband frequency range produces exceptional target separation and high-resolution returns, allowing anglers to distinguish individual fish from bait schools and clearly identify bottom composition and underwater structure. Its ability to reach 1,900 feet in freshwater provides reliable sonar coverage across most recreational and offshore fishing scenarios, while the 1,200-foot saltwater capability addresses deep-water coastal applications. The 20° internal tilt angle is specifically engineered to work with steep-deadrise hull designs, a critical specification that prevents signal distortion common in other transducers when improperly angled relative to the boat's keel.
Usage Instructions
Install the GT15M-THF using the included mounting hardware and installation guide, ensuring your hull deadrise falls between 16° and 24° for optimal sonar beam alignment. Connect the 8-pin transducer connector to a compatible Garmin chartplotter or sonar system. The Garmin Auto-ID technology automatically detects the transducer upon connection and applies the correct sonar configuration settings without manual adjustments, enabling immediate operational use. Verify water temperature sensor functionality by displaying live water temperature on your Garmin display to confirm proper installation.
Design & Material
The GT15M-THF features a robust stainless steel thru-hull construction engineered to withstand prolonged saltwater exposure, UV degradation, and mechanical impacts while maintaining corrosion resistance across multiple seasons. Its flush-mounted profile minimizes hydrodynamic drag and turbulence, while the internally tilted piezoelectric element delivers a consistently vertical sonar beam without external fairing blocks or epoxy fill compounds.
- Stainless steel thru-hull housing with corrosion-resistant finish
- Flush-mounted design that integrates seamlessly with hull contours
- 8-pin connector compatible with Garmin NMEA 0183 and proprietary sonar networks
- Internally tilted 20° piezoelectric element for beam optimization
- Integrated thermistor water temperature sensor with fast response time
- Suitable for fiberglass, composite, steel, aluminum, and wooden hulls
Final Verdict
The Garmin GT15M-THF 20° Stainless Steel Thru-Hull CHIRP Transducer is the ideal sonar solution for boaters with steep-deadrise hull designs who need reliable, high-definition underwater imaging without installation complexity. Its 1,900-foot freshwater and 1,200-foot saltwater depth capabilities, combined with exceptional 600-watt CHIRP clarity and automatic Garmin compatibility, make it a must-have for serious anglers and cruising enthusiasts. Order the GT15M-THF today to unlock precision sonar performance and transform how you read underwater structures and locate fish.
