Collection: Sounder/Sonar Modules

These modules separate the sonar processing unit from the display, letting you add or upgrade sonar capability without replacing your entire chartplotter system. The range here spans entry-level CHIRP echo sounders like the SI-TEX SCS-1000, through Garmin's GSD 24 network sounder and GCV 20 scanning sonar, up to high-power units like the Furuno DFF3-UHD TruEcho CHIRP and Simrad S5100. Technology varies considerably: traditional CHIRP bottom-sounding suits offshore and deep-water fishing, side-scan and StructureScan 3D from Navico reveals structure along the water column, and live sonar systems like the Garmin LiveScope Plus and Lowrance ActiveTarget 2 XL show fish moving in real time.

Compatibility is the single most important thing to confirm before buying. Furuno modules are built for NavNet TZtouch and TZtouch2 or TZtouch3 displays, the Navico StructureScan 3D is specific to HDS Gen3, NSS evo2, and NSO evo2 heads, and Raymarine modules pair with Axiom multifunction displays. Check your existing chartplotter's network type, available ports, and whether the transducer included suits your hull, since transom-mount and through-hull options are not interchangeable. Power supply requirements also differ across the higher-output units, so verify your vessel's electrical capacity before ordering.