Attwood 66547-3 Stainless Steel Straight Thru-Hull Fitting, 3/4 Inch Hose Barb, NPSM Thread

The Attwood 66547-3 is a straight stainless steel thru-hull valve fitting built for a permanent, corrosion-free through-hull connection below the waterline. It is a barbed, standard-length fitting sized for 3/4-inch interior diameter hose, making it a common choice for bilge, washdown, live well, and other below-waterline plumbing runs where a secure, leak-resistant penetration is required.

The fitting uses a 3/4-inch NPSM thread with a 1-inch thread outside diameter and a 2-inch thread length, paired with a 1 7/8-inch flange diameter that seats against the hull surface. The hose barb measures 1 1/4 inches long, and the fitting's total length is 3 3/4 inches. Installation calls for a 1 1/8-inch hole saw, and the fitting is rated for hulls up to a maximum thickness of 1 5/8 inches. It has a machined finish and two ports for through-hull flow.

Constructed of stainless steel for long-term durability in a marine environment, this fitting resists the corrosion that can compromise below-waterline hardware over time. It is sold as a single fitting.

Specifications

• Brand: Attwood
• Manufacturer Part Number: 66547-3
• Valve Type: Thru-Hull Valve Fitting
• Material: Stainless Steel
• Hose Barb Size: 3/4 Inch Interior Diameter
• Thread Type: 3/4 Inch NPSM
• Thread Outside Diameter: 1 Inch
• Thread Length: 2 Inches
• Flange Diameter: 1 7/8 Inches
• Barb Length: 1 1/4 Inches
• Overall Length: 3 3/4 Inches
• Installation Hole Saw Size: 1 1/8 Inches
• Maximum Hull Thickness: 1 5/8 Inches
• Number of Ports: 2
• Finish: Machined
• Weight: 0.5834 pounds

Frequently Asked Questions

What size hose does the Attwood 66547-3 fit? The Attwood 66547-3 is a barbed fitting sized for 3/4-inch interior diameter hose.

What thread does this thru-hull fitting use? It uses a 3/4-inch NPSM thread, with a 1-inch thread outside diameter and a 2-inch thread length.

What hole saw size is needed to install the 66547-3? A 1 1/8-inch hole saw is used to cut the mounting hole for the Attwood 66547-3.

What is the maximum hull thickness this fitting will work with? The Attwood 66547-3 is rated for hulls up to a maximum thickness of 1 5/8 inches.

What material is the 66547-3 made from? It is made of stainless steel, chosen for corrosion resistance in below-waterline marine use.

How long is the fitting overall? The Attwood 66547-3 has a total length of 3 3/4 inches, with a 1 1/4-inch barb.

What is the flange diameter on this fitting? The flange diameter on the 66547-3 is 1 7/8 inches.

Is this fitting straight or angled? The 66547-3 is a straight thru-hull valve fitting, not an angled design.

How many ports does the 66547-3 have? This Attwood thru-hull fitting has two ports.

What is the finish on the Attwood 66547-3? It has a machined stainless steel finish.

How much does the 66547-3 weigh? The Attwood 66547-3 weighs 0.5834 pounds.

Does the 66547-3 come as a single fitting? Yes, the Attwood 66547-3 is sold as a single thru-hull fitting.