Attwood Marine Standard Straight Barbed Thru-Hull Fitting, 316 Stainless Steel, Above-Water-Line
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Overview
The Attwood Marine Stainless Steel Thru-Hull Standard Straight Barbed is a straight hose thru-hull fitting for above-waterline plumbing on boats, offered in hose inner diameters from 5/8 inch to 1-1/2 inch. It is used where a hose needs a clean, secure exit through the hull for drains, bilge discharge, livewell plumbing, or similar topside water-handling runs.
The fitting is cast from enhanced 316 stainless steel, with visible surfaces polished to a mirror finish and passivated for added corrosion resistance. The straight barbed tail gives the hose a positive grip area, while the threaded body, flange, and gasket help create a controlled hull-side installation when paired with the proper marine sealant and clamps.
Key features
- Above-waterline thru-hull fitting for marine hose discharge and drain applications.
- Enhanced 316 stainless steel construction for use in saltwater, spray, and wet deck areas.
- Polished and passivated visible surfaces help maintain a clean exterior look on the hull.
- Straight barbed tail provides room for multiple hose clamps where the installation allows.
- Channel under the flange helps hold a bead of sealant during installation.
- Wrench flats or an end notch help one installer tighten the fitting from inside the hull.
- Full-length standard thread supports installation through thicker hull sections within the fitting size limits.
- Available for 5/8 inch, 3/4 inch, 1 inch, 1-1/8 inch, 1-1/4 inch, and 1-1/2 inch hose inner diameters.
Variants
This range varies by hose inner diameter, with six sizes covering common small-boat and cruising-boat plumbing needs: 5/8 inch, 3/4 inch, 1 inch, 1-1/8 inch, 1-1/4 inch, and 1-1/2 inch. The correct version is the one that matches the inside diameter of the hose being connected, not the outside diameter of the hose or the outside measurement of the barb.
The stainless steel straight barbed construction and above-waterline installation purpose remain consistent across the range. Installation dimensions such as flange diameter, thread outside diameter, thread length, hole saw size, and maximum hull thickness vary by fitting size, so those measurements should be checked for the specific diameter before drilling or replacing an existing thru-hull.
Installation and fit
Use this fitting only for above-waterline locations. Before installation, confirm the hose inner diameter, the hull thickness at the mounting point, the required hole size, and the space available inside the hull for the threaded section, backing hardware, hose bend, and clamps.
The flange should sit flat against a clean hull surface, with suitable marine sealant applied under the flange. The barbed end should be paired with marine hose of the correct size and secured with clamps appropriate for the hose and the service location.
Use cases on board
This fitting is a good match for boat owners replacing plastic above-waterline outlets with stainless hardware, or for builders and refit shops matching stainless thru-hulls to visible topside drains and discharge points. It suits exposed hull areas where appearance matters and where the fitting may see spray, washdowns, UV, and vibration during normal use.
Care and service
During routine maintenance, check the exterior flange, sealant line, hose connection, and clamps for movement, corrosion staining, or signs of leakage. Keeping the fitting rinsed after saltwater use and inspecting the hose connection at the start of the season helps catch installation issues before they become larger plumbing problems.
Shipping
We ship worldwide from the United States. Rates are calculated at checkout based on destination and package weight. Some items include free shipping, which will show automatically. Not every product is eligible for international shipping; checkout will confirm eligibility. We do not ship to PO Boxes except through USPS, and not all packages qualify.
Processing and dispatch
Most orders are verified, packed, and handed to the carrier within 1 to 2 business days. Some products may need extra handling time or ship directly from the manufacturer. For certain international orders, inventory transfers between warehouses may add time. If any delay is expected, we will let you know the dispatch date.
Delivery and tracking
Deliveries are handled by trusted carriers such as USPS, UPS, FedEx, and DHL. Estimated arrival times appear at checkout and depend on your location and the service you choose. These are estimates and can be affected by customs or carrier disruptions. A shipping confirmation with a tracking link is emailed when your order ships, and tracking may take up to 24 hours to update. You can also view tracking in your account.
Duties, taxes, and support
International customers are responsible for any customs duties, taxes, and fees charged by the destination country. If these charges are refused and a shipment returns to us, the carrier’s return cost and any re-entry customs fees will be deducted from the refund. If your order is late or you need help, contact cs@qualityboatparts.com and we will assist you.
Quality Boat Parts is a reseller. Many items include a manufacturer’s warranty, and all warranty service is handled directly by the manufacturer. We do not manage or administer warranty claims on behalf of customers.
Warranty terms, coverage, and duration are set by each manufacturer. Issues involving defects, repairs, or replacements must be addressed with the manufacturer’s support team. When available, the warranty period is listed on the product page. If it is not shown, contact us or the manufacturer for details before purchasing.
To start a claim, the customer must contact the manufacturer and follow their process. Keep your proof of purchase and original packaging, and register the product if the manufacturer requires it, as these are often needed for warranty service.
We are happy to help you find the right contact or documentation, but we cannot decide outcomes or intervene in claim resolutions. For guidance, email cs@qualityboatparts.com.
