Attwood Marine 90-Degree P-Trap Fuel Tank Vent, 5/8 in ID Hose, 3/4 in Install Hole, 9/16 in Max Hull Thickness, ABYC

Overview

The Attwood Marine 90° P-Trap Fuel Tank Vent is a surface-mount vent for permanently installed marine fuel systems using 5/8 inch I.D. vent hose. It helps the tank breathe during filling and normal operation while its baffled P-trap layout reduces the chance of splash water reaching the vent line, fuel tank, or carbon canister.

This vent is a practical fit for boat builders, refits, and fuel-system service work where a compact 90° vent is needed on the hull side. It uses a 3/4 inch installation hole, supports hull thickness up to 9/16 inch, and is made for normal sea conditions and washdowns where fuel-tank venting still needs to remain open.

The design can reduce or remove the need for an anti-siphon loop in the vent hose when the vent location allows it, which can simplify hose routing and help keep the run to the fuel tank shorter. It meets ABYC requirements and also meets ISO 10088 minimum venting-area requirements.

Key features

• Fits 5/8 inch I.D. fuel vent hose used on many marine fuel-tank installations.
• P-trap vent path helps block splash water while still letting air move freely through the fuel system.
• 3/4 inch installation hole and 9/16 inch maximum hull thickness support a clean surface-mount fit.
• 90° body helps route the vent hose inside the hull without a large straight-back clearance requirement.
• Can eliminate the need for an anti-siphon loop in the vent hose when the installation location is suitable.
• Removable cover allows access for vent inspection, debris removal, and fuel-system pressure testing.
• Meets ABYC requirements and ISO 10088 minimum venting-area requirements for marine fuel-tank venting.
• Compatible with ethanol-blended fuels for use in modern gasoline fuel systems.

Variants

This product is offered in two visible trim configurations for the same general vent style. The difference is the exterior head or cover finish, which affects how the vent appears on the hull after installation.

Both variants are 90° P-trap fuel tank vents for 5/8 inch I.D. hose. The shared vent function, hose size, installation-hole size, and marine fuel-system use remain consistent across the range.

• 1670-3 with black vent head. This version keeps the exterior appearance low-profile on dark hulls, painted surfaces, or hardware layouts where a black fitting blends in better.
• 66419-3 with stainless steel trim cover. This version adds a stainless trim face for installations where nearby deck or hull hardware has a brighter metal finish.

Installation and fit

Use this vent where the fuel tank requires a dedicated vent line to relieve air during filling and normal fuel draw. The 90° orientation is useful when space behind the hull side is limited or when a more direct hose path helps avoid unnecessary bends.

Check the hose size, hull thickness, and mounting location before installation. The vent should be placed where it can shed spray and washdown water properly, with the hose routed so it does not kink, sag in a way that traps fuel, or interfere with other fuel-system components.

Use on board

This vent is a good match for small to mid-size powerboats, fishing boats, runabouts, and refit projects that need a replacement fuel-tank vent with water-resistance built into the fitting. It is especially useful where the outside vent must handle spray, rain, and routine washdowns without giving up free airflow to the tank.

For service work, the removable cover helps with inspection and cleaning around the vent opening. That matters on boats stored outdoors or used in areas where salt, dirt, wax, or dockside debris can collect around hull fittings over time.