Attwood 66548-3 Stainless Steel Barbed Straight Thru-Hull Fitting, 1-Inch Hose, Standard Length

The Attwood 66548-3 is a stainless steel straight thru-hull fitting built to install securely through a boat's hull and deliver long-term, corrosion-free performance in the marine environment. It is a barbed, standard-length fitting designed for use with 1-inch inside diameter hose, making it a common choice for below-deck plumbing runs such as bilge, washdown, or raw water intake lines that need a reliable hull penetration point.

The fitting features a 2-1/4 inch flange diameter that seats against the hull for a solid seal, a 1-3/8 inch thread outside diameter with 2-1/4 inch of thread length, and a 1-inch NPSM thread. The barb itself measures 1-1/4 inch long, and the fitting's total length is 3-7/8 inches. It requires a 1-1/2 inch installation hole and is rated for hulls up to 1-3/4 inch thick. Constructed of stainless steel, it resists the corrosion that can affect lower-grade metal fittings over time.

Specifications

• Brand: Attwood
• Manufacturer Part Number: 66548-3
• Material: Stainless Steel
• Connector Type: Barb
• Hose Size: 1 inch I.D.
• Thread Type: NPSM
• Thread Size: 1 inch
• Thread Outside Diameter: 1-3/8 inches
• Thread Length: 2-1/4 inches
• Flange Diameter: 2-1/4 inches
• Barb Length: 1-1/4 inches
• Total Length: 3-7/8 inches
• Installation Hole Size: 1-1/2 inches
• Maximum Hull Thickness: 1-3/4 inches
• Weight: 0.8833 pounds

Frequently Asked Questions

What size hose fits the Attwood 66548-3 thru-hull fitting? This thru-hull fitting is barbed for 1-inch inside diameter hose, and the 66548-3 designation refers to this specific hose size and length combination.

Is the 66548-3 a barbed or threaded thru-hull fitting? It is a barbed fitting, meaning the hose pushes directly onto the barb rather than connecting to a threaded pipe fitting.

What material is the Attwood 66548-3 thru-hull made from? Stainless steel, chosen for corrosion resistance in below-deck marine plumbing applications.

What size hole do I need to drill to install this fitting? A 1-1/2 inch installation hole is required to mount the Attwood 66548-3 thru-hull fitting.

What is the maximum hull thickness this fitting will work with? The 66548-3 accommodates hulls up to 1-3/4 inch thick, based on its 2-1/4 inch thread length.

How long is the Attwood 66548-3 overall? 3-7/8 inches from end to end, with a 1-1/4 inch barb and 2-1/4 inch of NPSM thread.

What is the flange diameter on this thru-hull fitting? 2-1/4 inches, which is the diameter of the flange that seats against the hull surface for the 66548-3.

What thread type does the Attwood 66548-3 use? A 1-inch NPSM thread with a 1-3/8 inch thread outside diameter.

How much does this thru-hull fitting weigh? The Attwood 66548-3 weighs 0.8833 pounds.

Is this a genuine Attwood part or an aftermarket copy? The 66548-3 is a genuine Attwood-manufactured stainless steel thru-hull fitting, not a generic aftermarket substitute.