Attwood Thru-Hull Fitting for 3/4 Inch Hose, White, 3873-3

The attwood 3873-3 is a thru-hull fitting designed to create a secure, reliable connection point where plumbing or drainage hose passes through a boat's hull. Built in white polypropylene, it resists corrosion and UV exposure better than metal alternatives, making it well suited to bilge pump discharge, livewell drains, washdown lines, and other below-waterline plumbing runs. The fitting is sized for 3/4 inch inside diameter hose, with a stem length of 3-1/4 inches to pass through hull material and a flange diameter of 2-1/4 inches to seat against the hull surface and spread clamping load evenly. It accommodates a maximum hull thickness of 1-1/4 inches, covering typical fiberglass and composite hull sections found on small to mid-size boats.

Installation follows standard thru-hull practice: the stem passes through a drilled hole in the hull, the flange seats against the exterior or interior surface with appropriate marine sealant, and the hose clamps directly onto the barbed stem. The white finish blends with common hull gelcoat colors, and the polypropylene construction is lightweight, will not corrode, and holds up to continuous exposure to fresh and salt water.

Specifications

• Brand: attwood
• Manufacturer Part Number: 3873-3
• Product Type: Thru-Hull Fitting
• Color: White
• Material: Polypropylene
• Hose Inside Diameter: 3/4 inch
• Stem Length: 3-1/4 inches
• Maximum Hull Thickness: 1-1/4 inches
• Flange Diameter: 2-1/4 inches
• Weight: 0.2 pounds

Frequently Asked Questions

What size hose does the attwood 3873-3 thru-hull fitting fit? The attwood 3873-3 is sized for 3/4 inch inside diameter hose.

What is the maximum hull thickness this fitting can be used with? The 3873-3 accommodates hulls up to 1-1/4 inches thick.

How long is the stem on this thru-hull fitting? Stem length is 3-1/4 inches, which is the portion that passes through the hull.

What is the flange diameter of the attwood 3873-3? The flange measures 2-1/4 inches in diameter, providing the seating surface against the hull.

What material is the attwood 3873-3 thru-hull fitting made from? It is made from polypropylene, a corrosion-resistant, lightweight plastic suited to marine plumbing use.

What color is this thru-hull fitting? The 3873-3 is finished in white.

How much does the attwood 3873-3 weigh? It weighs 0.2 pounds.

What is a thru-hull fitting used for? A thru-hull fitting like the 3873-3 provides a sealed passage point through the boat's hull for plumbing lines such as bilge pump discharge, livewell drains, or washdown hose.

Does the attwood 3873-3 require sealant during installation? Yes, standard thru-hull installation calls for marine sealant between the flange and hull surface to prevent water intrusion; the fitting itself does not include sealant.

Will the attwood 3873-3 corrode over time in saltwater use? No, because it is made of polypropylene rather than metal, the 3873-3 will not corrode in fresh or saltwater environments.

Is the hose clamped directly onto the attwood 3873-3? Yes, the stem is barbed so 3/4 inch inside diameter hose can be pushed on and secured with a hose clamp.