Attwood 3876-3 Thru-Transom Scupper Valve with Flapper, Acetal, for 1-1/2 Inch I.D. Hose

The Attwood 3876-3 is a thru-transom scupper valve built for self-bailing cockpits. Its rubber flapper opens under water pressure to let cockpit water drain overboard, then closes to stop water from washing back in through the same opening. The valve body is molded from Acetal, a rigid, corrosion-resistant plastic that holds up well against saltwater and UV exposure, and it is sized to connect to 1-1/2 inch I.D. Hose. It is designed to be mounted over an existing thru-hull fitting of up to 2 inches, and the assembly itself has an overall diameter of 2-7/8 inches.

The kit includes everything needed for the install: a corrosion-resistant retainer ring, mounting screws, the rubber flapper valve, and a gasket, for four pieces total in the box. This is a simple, one-way check valve setup, meaning it only allows water to flow in one direction, out of the boat, protecting the cockpit from backwash while underway or at rest. Installation is intended for above the waterline only; as with other plastic thru-hull connectors, it is not designed for below-waterline use. This makes it well suited for boats with self-bailing cockpit decks that need a reliable, low-maintenance drain valve that will not corrode like metal alternatives.

Specifications

• Brand: Attwood
• Manufacturer Part Number: 3876-3
• Product Type: Thru-Transom Scupper Valve
• Material: Acetal
• Valve Type: Check valve (flapper style)
• Hose Connection: For 1-1/2 inch I.D. Hose
• Thru-Hull Mounting Fitting Size: Up to 2 inches
• Overall Diameter: 2-7/8 inches
• Item Dimensions: 4.5 x 9.25 x 3.5 inches
• Installation: Above the waterline only
• Included Components: Retainer ring, mounting screws, rubber flapper valve, gasket
• Number of Pieces: 4
• Weight: 0.3 pounds
• UPC: 022697387639

Frequently Asked Questions

What does the Attwood 3876-3 scupper valve do? It drains water out of a self-bailing cockpit through a rubber flapper that opens under water pressure to let water flow out, then closes to prevent water from washing back in.

What hose size does the 3876-3 fit? The Attwood 3876-3 is sized for 1-1/2 inch I.D. Hose.

Can this valve be installed below the waterline? No. Like other plastic thru-hull connectors, the 3876-3 is designed for installation above the waterline only.

What is the scupper valve made of? The 3876-3 body and flapper assembly are made of Acetal, a rigid plastic that resists corrosion in marine environments.

What is included in the box with the 3876-3? The kit ships with a retainer ring, mounting screws, the rubber flapper valve, and a gasket, four pieces in total.

What size thru-hull fitting does the 3876-3 mount over? It is designed to be mounted over an existing thru-hull fitting of up to 2 inches in diameter.

How big is the Attwood 3876-3 overall? The assembly has an overall diameter of 2-7/8 inches, with item dimensions of 4.5 x 9.25 x 3.5 inches.

Is the 3876-3 a one-way valve? Yes, it functions as a check valve: the rubber flapper opens to let water drain out and closes to block backwash, allowing flow in one direction only.

How much does the Attwood 3876-3 weigh? The scupper valve weighs 0.3 pounds.

Is the Attwood 3876-3 a genuine Attwood part? Yes, the 3876-3 is a genuine Attwood scupper valve, part of Attwood's thru-transom valve lineup for self-bailing cockpits.

What boats is the 3876-3 scupper valve suitable for? It is intended for boats with self-bailing cockpit decks that need a thru-transom drain valve mounted above the waterline.