GROCO TH-750-W Bronze 3/4 Inch NPS/NPT Combo Thru-Hull Fitting with Nut

The GROCO TH-750-W is a bronze thru-hull fitting sized for 3/4 inch plumbing, built to pass through a boat's hull below or above the waterline for intake or discharge plumbing runs such as raw water intake, cockpit drains, livewell lines, or washdown systems. It uses a combination NPS/NPT thread design, allowing it to accept either straight NPS (National Pipe Straight) or tapered NPT (National Pipe Thread) fittings on the inboard side, giving installers flexibility when connecting hose barbs, seacocks, or strainers. The fitting is cast in bronze for corrosion resistance in saltwater and freshwater marine environments, and it includes a matching nut for securing the fitting against the hull from the inside.

The mushroom-style flanged head sits flush against the hull's exterior surface while the threaded shaft passes through the hull wall, with the nut drawn up on the inside to clamp the assembly tight. This is a single-piece fitting (one nut included) intended to be bedded with marine sealant during installation to ensure a watertight seal. Because it is bronze rather than plastic, the TH-750-W is suited for permanent, below-waterline installations where long-term corrosion resistance and strength are priorities over lighter-weight alternatives.

Specifications

• Brand: GROCO
• Manufacturer Part Number: TH-750-W
• Product Category: Thru Hull Fittings & Strainers
• Thread Size: 3/4 inch
• Thread Type: Combination NPS (National Pipe Straight) and NPT (National Pipe Thread)
• Material: Bronze
• Finish/Color: Bronze
• Included Components: Thru-hull fitting with nut
• Number of Pieces: 1
• Item Dimensions: 12 x 6.25 x 6.5 inches
• Weight: 0.5 pounds
• UPC: 742985064102

Frequently Asked Questions

What size thread does the GROCO TH-750-W use? The TH-750-W has a 3/4 inch thread that is machined as a combination NPS/NPT design, meaning it can accept either straight NPS or tapered NPT connections on the inboard side.

Is the TH-750-W made of bronze or plastic? The TH-750-W is a bronze thru-hull fitting, chosen for corrosion resistance in both saltwater and freshwater marine environments.

Does this fitting come with a nut? Yes, the TH-750-W includes a matching nut that threads onto the inboard side of the fitting to clamp it against the inside of the hull.

Can the TH-750-W be installed below the waterline? Bronze construction makes the TH-750-W suitable for below-waterline installations such as raw water intakes and discharge lines, provided it is properly bedded with marine sealant.

What does NPS/NPT combo thread mean on this fitting? It means the TH-750-W's threads are cut to work with either NPS (National Pipe Straight) or NPT (National Pipe Thread) fittings, giving more flexibility when connecting hose adapters or valves.

What is included with the GROCO TH-750-W? The package includes one TH-750-W bronze thru-hull fitting and its corresponding nut; it does not include hose barbs, seacocks, or sealant.

How many pieces come in one TH-750-W unit? One TH-750-W unit consists of a single fitting and nut assembly, listed as one piece.

How much does the TH-750-W weigh? The GROCO TH-750-W weighs 0.5 pounds.

What is a thru-hull fitting used for? A thru-hull fitting like the TH-750-W creates a sealed passage through a boat's hull for plumbing lines such as intake water, drains, or washdown systems.

Why choose a bronze thru-hull over a plastic one? Bronze fittings like the TH-750-W resist corrosion and hold up to long-term below-waterline exposure better than plastic alternatives, making them a common choice for permanent installations.

Does the TH-750-W require sealant during installation? Yes, the fitting should be bedded with marine sealant where it passes through the hull to ensure a watertight seal between the fitting flange and the hull surface.