Garmin GT17M-THF Replacement Jam Nut

The Garmin GT17M-THF Replacement Jam Nut is a critical fastening component for anglers and boaters relying on Garmin's transducer systems for reliable depth and fish-finding performance. This jam nut secures the transducer housing to the thru-hull mounting assembly, ensuring zero movement and preventing water intrusion that could compromise sonar accuracy or cause costly leaks below the waterline. If your existing nut has corroded, stripped, or loosened from years of saltwater exposure and engine vibration, replacement is straightforward and essential to maintain the integrity of your fish-finder setup.

Marine-grade fasteners like this jam nut are engineered to withstand constant thermal cycling, UV degradation, and electrolytic corrosion inherent to saltwater and freshwater boating environments. The jam nut design locks onto the threaded transducer stem, creating a dual-compression seal against the thru-hull fitting that prevents both loosening and water seepage. Weighing approximately 1 pound, this component is manufactured to Garmin's OEM specifications (MPN 010-13348-00), ensuring perfect fit and thread compatibility with GT17M-THF transducer assemblies used on countless recreational and fishing vessels.

Boaters who have noticed sonar dropouts, intermittent signal loss, or water pooling around their transducer head often find the culprit is a deteriorated jam nut allowing micro-movement or seepage. Installation requires only a wrench and takes minutes—remove the old nut, clean the threads, apply marine-grade sealant if needed, and hand-tighten the new nut until snug. This replacement is compatible exclusively with Garmin GT17M-THF through-hull transducers and is backed by the brand's reputation for marine electronics reliability, making it the correct OEM fix for restoring stable sonar performance and preventing further hull damage.