Collection: Thru-Hull Fittings

Penetrating the hull is one of the most consequential decisions in any marine plumbing project, so material and sizing matter from the start. Outdoors Marine stocks thru-hull fittings from GROCO, Perko, and Attwood Marine, covering the most common needs on recreational and working boats. GROCO's stainless steel and bronze combo fittings accept both NPS and NPT threads, which simplifies connecting to the widest range of hoses and fittings already on your boat. Bronze suits most traditional installations where galvanic compatibility with other bronze or brass hardware is a priority, while stainless is a strong choice in high-visibility or higher-corrosion-risk locations. Attwood's plastic fittings work well for lighter-duty above-waterline applications where weight savings and cost are factors.

Before ordering, confirm the hole size your hull already has or the size you plan to cut, since fittings here run from 1/2 inch up to 2 inches. Match the thread type to whatever valve or seacock you plan to pair with the fitting, and verify that your chosen material is compatible with neighboring metals to avoid accelerated galvanic corrosion. All products are sold through Outdoors Marine as an authorized dealer, so you receive genuine manufacturer-backed hardware. Orders that qualify ship free.