GROCO 1-1/4" #316 Stainless Steel NPS to NPT Flange Adapter

The GROCO 1-1/4" #316 Stainless Steel NPS to NPT Flange Adapter serves as a critical safety component for boaters looking to secure through-hull fittings with maximum structural integrity. In the marine world, connecting straight-threaded (NPS) through-hull fittings directly to tapered-threaded (NPT) valves is a common but dangerous practice that often leads to compromised seals. This adapter solves that problem by providing a secure, flanged transition that ensures a watertight and mechanically sound connection below the waterline. It is an essential piece of hardware for anyone upgrading their plumbing or installing new seacocks in a corrosive saltwater environment.

Constructed from premium #316 stainless steel, this GROCO 1-1/4" #316 Stainless Steel NPS to NPT Flange Adapter offers exceptional resistance to pitting and crevice corrosion in harsh marine conditions. The IBVF series design features a wide flange that effectively distributes the load across the hull surface, preventing localized stress on fiberglass or wood. By converting the NPS threads of the through-hull to NPT threads, it allows for the safe installation of standard in-line ball valves without the risk of cross-threading or insufficient thread engagement. The heavy-duty 1.25-pound build ensures long-term durability and peace of mind when venturing far offshore.

Engineered for professional-grade installations, the GROCO 1-1/4" #316 Stainless Steel NPS to NPT Flange Adapter is the preferred choice for vessel owners who demand reliability in their raw water intake or discharge systems. This adapter is specifically designed to work with 1-1/4 inch fittings, making it compatible with a wide range of standard marine plumbing components used in bilge, engine cooling, and livewell systems. Proper installation of this adapter significantly reduces the risk of catastrophic failure at the through-hull, which remains a leading cause of preventable vessel sinking. Whether you are performing a seasonal refit or building a new offshore craft, this stainless steel adapter provides the professional security your boat deserves.