Overview

The Attwood Marine 3878-3 is a white polypropylene double-ended thru-hull connector for 3/4 inch I.D. hose, with a 1-1/8 inch installation hole size and a 1-1/8 inch maximum hull thickness.

It creates a clean pass-through where a hose needs to move through a bulkhead or tank wall above the waterline. The double-ended layout keeps the hose connection on both sides of the panel, and the 5 inch overall length gives enough reach for common marine plumbing runs without taking up much room.

This fitting makes sense for above-waterline drain, vent, or transfer lines where you need a simple connector that matches 3/4 inch hose and mounts through a finished surface. It is not a below-waterline thru-hull, so fit and mounting location matter before installation.

Key features

• Fits 3/4 inch inside diameter hose
• Double-ended thru-hull form for routing a hose through a bulkhead or tank wall
• 1-1/8 inch installation hole size for planning the cutout before mounting
• 1-1/8 inch maximum hull or panel thickness
• 5 inch overall length for reaching through the mounting surface and accepting hose on both ends
• White polypropylene body for marine plumbing use above the waterline

Compatibility and fit

This connector is a good match when your boat already uses 3/4 inch I.D. hose and the mounting surface stays within the 1-1/8 inch thickness limit. On small fishing boats, runabouts, skiffs, and utility boats, that usually means splashwell drains, locker drains, livewell or washdown plumbing, or tank and compartment pass-through points that stay above the static waterline.

Before ordering, check the hose inside diameter, confirm that a 1-1/8 inch mounting hole works in the available space, and make sure there is room for the hose bend radius on both sides of the panel. That matters more on tight transom corners, shallow lockers, and compact rigging spaces.

Installation and setup

Because this is a straight double-ended connector, installation is usually straightforward when the hose run is already planned. It suits refits where an older plastic fitting has cracked, yellowed, or started leaking around the panel, and it also works well when adding a new pass-through in a tank wall or interior partition.

For the cleanest result, use hose that matches the 3/4 inch I.D. size, support the plumbing run so vibration does not load the fitting, and keep it in an above-waterline location only. That makes it a sensible choice for owners who want a simple plumbing connector without switching hose size or reworking the whole run.