GROCO 1-1/4" Bronze High Speed Thru-Hull Fitting w/Nut

The GROCO 1-1/4" Bronze High Speed Thru-Hull Fitting w/Nut is purpose-built for serious boaters and anglers who demand reliable through-hull plumbing without compromise. Whether you're running raw water cooling, livewell circulation, or bilge discharge on a center console, sportfisher, or cruising vessel, this fitting handles the demands of extended time on the water. High-speed thru-hull fittings are engineered to replace standard fittings when flow rate matters—situations where cooling efficiency or baitwell turnover directly affects boat performance and fish survival.

Machined from C83600 bronze, this fitting resists corrosion in saltwater and brackish environments while maintaining structural integrity under pressure cycling. The 1-1/4" bore delivers significantly increased flow compared to standard thru-hulls, reducing restriction and drag on your cooling or circulation systems. The combination NPSM/NPT thread design provides flexibility during installation, allowing you to mate with either pipe thread or straight thread fittings depending on your plumbing configuration. The integral nut simplifies fastening to the hull from below the waterline, a critical detail when you're working in tight engine compartments or below-deck spaces.

This fitting is ideal for retrofit cooling upgrades, livewell rebuilds, or new construction where raw water volume is critical to system performance. Anglers running large baitwells or tournament boats benefit from the superior flow rates that keep bait fresh and lively throughout the day. At 1.05 lbs and compact 3 x 3 x 4 inch dimensions, it fits tight installation spaces without requiring extensive hull modifications. Compatibility extends across most recreational and commercial vessel types where 1-1/4" through-hull plumbing is specified—verify your existing fitting bore and thread type before ordering to ensure proper fit.