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

The GROCO 1" Bronze Extra Long High Speed Thru-Hull Fitting with Nut is a marine through-hull component engineered for optimal fluid flow and reduced drag in demanding boating applications. Built from C83600 bronze—a corrosion-resistant marine-grade alloy—this thru-hull fitting combines extra-long thread engagement with high-speed design principles to deliver superior performance compared to standard thru-hull assemblies. Whether you're running cooling systems, intake lines, or seawater applications on fishing vessels, cruisers, or offshore powerboats, this fitting prioritizes both reliability and efficiency in saltwater environments.

The extra-long NPSM/NPT combination thread design accommodates deeper hull installations and provides maximum sealing surface for a watertight connection. The 1-inch diameter sizing suits mid-to-large displacement vessels where consistent flow rate is critical—the high-speed profile minimizes turbulence and pressure drop that can compromise system efficiency. C83600 bronze resists dezincification and stress corrosion cracking, making it suitable for continuous exposure to saltwater and brackish conditions. The included nut simplifies installation, securing the fitting firmly to the hull without requiring specialized fastening hardware.

This fitting is designed for boaters and marine mechanics who need a reliable, long-service-life thru-hull component that handles high-volume flow without the pressure losses associated with standard geometry. It's particularly valued in cooling system upgrades, transom well installations, and raw-water intake applications where both durability and performance matter. Serious offshore anglers, commercial fishing operators, and cruising sailors depend on GROCO through-hull fittings to maintain system integrity across seasons of use.