Perko 0348 Extra Long Thru-Hull Connection, Cast Bronze, NPT/S

Overview

The Perko Figure No. 0348 is an extra long thru-hull connection for use with pipe on marine plumbing installations where the hull section requires more threaded length than a standard fitting. It is made from cast bronze with a plain finish and uses a machined flange with a bedding groove to help retain sealant during installation.

This fitting is used where a pipe-thread thru-hull is needed for intakes, discharges, drains, and other onboard plumbing runs that pass through the hull. The listed configurations cover 3/4 in, 1 in, 1-1/4 in, and 1-1/2 in pipe sizes, with mounting hole diameters from 1 in to 1-7/8 in and maximum hull thickness ratings up to 5 in depending on size.

The neck is threaded to approximately 3/8 in from the flange, giving the installer usable thread engagement while keeping the flange seated cleanly against the hull surface. As with any thru-hull fitting, final suitability depends on the vessel layout, seacock or valve arrangement, pipe size, hull thickness, and installation practices for the specific location.

Key features

• Cast bronze construction for marine thru-hull plumbing applications where metal hardware is preferred.
• Extra long body helps accommodate thicker hull sections, with maximum hull thickness up to 5 in on the 3/4 in configuration.
• Machined flange has a groove that helps hold bedding compound at the hull surface during installation.
• Threaded neck reaches to approximately 3/8 in from the flange for pipe-thread connections.
• Plain bronze finish suits underwater hardware installations where coating, bonding, and service access are handled as part of the boat’s plumbing setup.
• Available in multiple pipe sizes so the fitting can be matched to the planned through-hull opening and connected plumbing.

Variants

This Perko thru-hull connection is offered in several pipe-size configurations for different plumbing runs and hull openings.

The pipe size, mounting hole diameter, and maximum hull thickness change by variant. The cast bronze material, plain finish, machined bedding-groove flange, and neck threaded to approximately 3/8 in from the flange are consistent across the Figure No. 0348 configurations.

• 0348DP5PLB: 3/4 in pipe size, 1 in mounting hole diameter, and 5 in maximum hull thickness. This is the smallest listed configuration and fits installations using 3/4 in pipe with the deepest hull-thickness allowance in this group.
• 0348DP6PLB: 1 in pipe size, 1-5/16 in mounting hole diameter, and 4-7/8 in maximum hull thickness. This size suits plumbing layouts that step up to 1 in pipe while still allowing for a thick hull section.
• 0348DP7PLB: 1-1/4 in pipe size, 1-5/8 in mounting hole diameter, and 4-5/8 in maximum hull thickness. This configuration is used where the plumbing run calls for a larger 1-1/4 in pipe connection.
• 0348DP8PLB: 1-1/2 in pipe size, 1-7/8 in mounting hole diameter, and 4-5/8 in maximum hull thickness. This is the largest listed configuration in this selection and requires the widest mounting hole among the four variants.

Installation and fit

Before ordering, match the pipe size to the connected plumbing and confirm that the required mounting hole can be drilled safely in the selected hull location. The maximum hull thickness rating is size-specific, so it should be checked against the actual laminate, backing, fairing, and any interior structure at the installation point.

The bedding groove on the flange is useful when sealing the fitting to the hull because it gives the compound a place to sit as the flange is tightened. The fitting should be installed with the correct marine sealant, proper backing where required, and a compatible seacock or valve arrangement when the installation passes through the hull below or near the waterline.

Use on board

This fitting is a practical match for refit work, repair jobs, and new plumbing installations where an extra long bronze pipe-thread thru-hull is needed. It is especially relevant for boats with thicker hull sections or locations where standard-length thru-hulls do not leave enough usable thread for the connected hardware.

Maintenance and care

After installation, inspect the flange area, bedding seal, threads, and connected plumbing as part of routine bilge and haul-out checks. Bronze thru-hull fittings should be kept compatible with the vessel’s bonding and corrosion-control plan, and any signs of dezincification, movement, leakage, or damaged threads should be addressed before the boat returns to service.