The Garmin GT15M-THF is a flush-mount, stainless steel thru-hull transducer built for midsize fishing and cruising vessels. Running mid-band CHIRP sonar at 85–165 kHz, it delivers sharp fish arches, clear structure definition, and reliable bottom readings to 1,200 ft in saltwater and 1,900 ft in freshwater — all with minimal hull drag. Garmin Auto-ID means the connected chartplotter recognizes and configures itself to this transducer automatically, and compatibility spans fiberglass, composite, steel, aluminum, and wood hulls.

Specifications:

• Sonar Type: Mid-band CHIRP traditional sonar
• Frequency Range: 85–165 kHz
• Power Output: 600 W
• Beam Width: 16–24 degrees
• Maximum Depth: 1,200 ft saltwater / 1,900 ft freshwater
• Cable Length: 50 ft
• Sensor Outputs: Depth and temperature
• Connector: 8-pin
• Supported Hull Deadrise: 20-degree version accommodates 16–24 degree deadrise angles (no fairing block required)
• Compatible Hull Materials: Fiberglass, composite, steel, aluminum, wood
• Housing Material: Stainless steel
• Mounting Style: Thru-hull flush mount
• Auto-ID: Yes — plug-and-play with compatible Garmin chartplotters

In the Box:

• GT15M-THF transducer
• Jam nut
• Washer
• Thread isolator
• Hull isolator
• Documentation

Resources:

• Installation Guide (PDF)