Perko 0350 Thru-Hull Connection, Plain Bronze, Hose Barb, Above Waterline

Overview

The Perko Thru-Hull Connection for use with Hose is a plain bronze thru-hull fitting for routing hose discharge through the hull on above-waterline installations. The range shown here covers hose sizes from 5/8 inch to 1-1/2 inch, with mounting hole diameters from 13/16 inch to 1-7/8 inch and maximum hull thickness ratings from 1-1/16 inch to 1-7/8 inch, depending on the selected size.

Each fitting is made from cast bronze with a plain finish. The flange is machined to sit tightly against the hull and includes a bedding groove to help retain sealant during installation. The neck is threaded to approximately 3/16 inch from the flange, which helps with nut engagement while leaving room for the flange and bedding compound to seat properly.

This fitting is not recommended for use below the waterline. It suits above-waterline hose outlets such as cockpit drains, sink drains, livewell or baitwell overflows, and similar discharge points where the hose size, hull thickness, and mounting hole can be matched before drilling.

Key features

• Plain cast bronze construction for marine plumbing applications where bronze hardware is preferred.
• Machined flange with a bedding groove to help hold sealant at the hull surface during installation.
• Threaded neck extends to approximately 3/16 inch from the flange for secure nut installation.
• Available in hose sizes from 5/8 inch through 1-1/2 inch in the listed configurations.
• Mounting hole and maximum hull thickness vary by size, making fit confirmation important before replacing an existing thru-hull.
• Intended for above-waterline hose connections and not recommended for below-waterline use.

Variants

This Perko thru-hull connection is offered in several hose-size configurations. Across the listed plain bronze variants, the main differences are hose size, mounting hole diameter, maximum hull thickness, and flange outside diameter.

The smaller sizes suit lighter hose runs and tighter locations, while the larger sizes allow higher-capacity drains or discharge lines where the boat already uses a matching hose and hull opening. Before ordering, match the hose inside diameter, check the drilled hole requirement, and confirm that the hull thickness at the mounting point stays within the listed limit for that configuration.

Installation and fit

Fit should be checked from both sides of the hull before installation. The hose size must match the plumbing run, the mounting hole must match the selected fitting, and the hull thickness must not exceed the rating for that variant. The flange seats on the exterior surface, so the surrounding hull area should be fair enough for sealant to compress evenly.

Because the flange includes a bedding groove, sealant can remain concentrated where the fitting meets the hull. As with any thru-hull work, the hole edge, bedding surface, backing area, nut, and hose clamp access should all be planned before final assembly.

Use cases on board

This fitting is a practical match for boat owners replacing an existing above-waterline bronze thru-hull or laying out a new hose discharge where plain bronze hardware is specified. It is especially relevant on fishing boats, cruisers, and sailboats with drain or overflow plumbing that exits through the topsides or transom above the static waterline.

Maintenance and care

Inspect the fitting as part of regular hull and plumbing checks, especially around the flange, bedding compound, hose connection, and retaining nut. Look for movement, staining, cracked sealant, hose wear, or clamp corrosion, and address any issue before the boat returns to service.