GROCO 2" NPS NPT Combo Stainless Steel Thru-Hull Fitting w/Nut

The GROCO 2" NPS NPT Combo Stainless Steel Thru-Hull Fitting with Nut is the backbone of reliable through-hull plumbing on serious fishing boats and cruising vessels. After decades on the water, any experienced angler knows that a thru-hull fitting is where saltwater corrosion begins—and where it must be stopped. This combo fitting serves raw water intakes, livewell systems, engine cooling loops, and bilge discharge applications, making it indispensable for any boat running hard in coastal or offshore environments. The 2-inch bore handles substantial flow rates without backpressure, critical when you're running multiple systems or need fast water exchange in a livewell.

Built from #316 stainless steel, this fitting resists pitting and crevice corrosion far better than standard 304 grade, essential in saltwater service where chloride exposure is constant. The NPSM/NPT combination thread design accommodates both national pipe taper and straight-pipe connections, giving you flexibility whether you're adapting to threaded hose barbs, compression fittings, or seacock valves. UL Listed to standard 647B, the fitting meets marine safety and performance requirements for pressure-rated applications. The included nut simplifies deck-side installation and provides positive mechanical grip, reducing the risk of spin-out during initial assembly or maintenance haul-outs.

This fitting is essential for rebuilding aged plumbing systems or upgrading boats with marginal through-hull hardware. Cruising anglers and tournament bass boats alike depend on GROCO fittings because failure below the waterline is not an option—it's a disaster waiting to happen. Installation requires proper bedding with marine sealant and a backing block on the interior hull, standard practice that ensures longevity and prevents leaking at the critical hull penetration. The 2-inch size is the sweet spot for most center console and cabin boats, handling everything from raw water cooling to washdown systems without restriction.