Attwood Marine 90 Degree Thru-Hull Connector, White Polypropylene, Above-Waterline

Overview

The Attwood Marine 90 Degree Thru-Hull Connector is a white plastic elbow fitting for above-the-waterline marine drain and overflow plumbing where a straight thru-hull would put the hose in a hard bend. Its 90 degree outlet helps route hose cleanly in tight spaces such as livewell overflow drains, baitwell drains, cockpit drain layouts, and other small-boat plumbing runs that need a low-profile turn at the hull.

The fitting is made from white polypropylene and is available for two hose sizes: 3/4" inner diameter and 1-1/8" inner diameter. The smaller version uses a 1" installation hole and supports hull thickness up to 1", while the larger version uses a 1-5/16" installation hole and supports hull thickness up to 1-7/8".

Key features

• 90 degree thru-hull layout helps the hose make a tight turn without kinking behind the hull surface.
• White polypropylene construction will not rust and is suited to above-the-waterline marine plumbing installations.
• Commonly used for livewell overflow drains and similar drain or overflow runs where space behind the hull is limited.
• Available in 3/4" and 1-1/8" inner diameter configurations to match different hose sizes.
• Angled outlet supports cleaner hose routing in lockers, transoms, splash wells, and confined plumbing spaces.

Variants

This thru-hull connector is offered in two size configurations for different hose inner diameters.

The 90 degree form, white color, polypropylene construction, and above-the-waterline use remain consistent across the two options. The hose size, installation hole size, flange diameter, hull thickness capacity, and drain plug size vary by part number.

• 3877-3: Inner diameter 3/4". This size fits 3/4" I.D. hose and uses a 1" installation hole, with a 1-1/2" flange diameter, 1" maximum hull thickness, and 1/2" drain plug size.
• 3879-3: Inner diameter 1-1/8". This larger size fits drain or overflow runs that call for 1-1/8" I.D. hose and uses a 1-5/16" installation hole, with a 2-7/16" flange diameter, 1-7/8" maximum hull thickness, and 7/8" drain plug size.

Installation and fit

Match the selected variant to the hose inner diameter already used in the drain or overflow run. The hose should sit squarely on the barb without forcing a smaller hose over the fitting or leaving a larger hose loose on the outlet.

Before cutting or replacing an existing fitting, check the hull thickness at the mounting point and confirm that the installation hole size matches the selected connector. This is especially important on cored hull sections, liners, transom wells, and molded livewell areas where the available thickness may differ from what is visible at the surface.

Use on board

This fitting is a practical match for small-boat plumbing jobs where the hose needs to turn immediately after passing through the hull side or livewell wall. It is most useful in tight compartments where a straight thru-hull would force the hose into a sharp bend.

Plastic thru-hull connectors of this type are for above-the-waterline installations. For underwater fittings, seacocks, or continuously submerged plumbing, use hardware rated for that specific location and follow the vessel builder’s plumbing layout.