The American Boat & Yacht Council defines a thru hull as a device that allows the passage of gases or liquids through a hull. Thru hulls may be located above or below waterline depending upon their purpose.  They are fully threaded (NPS thread) so they can be cut to the correct length for your hulls thickness and then be threaded into a female straight threaded valve or a flanged adapter. The most common types of thru hulls are the mushroom head style and the flush head style. While the mushroom head style slightly protrudes from the outer hull of the boat, the flush head style is slightly countersunk to make it even with the level of the hull.

Every thru hull fitting in a boat is a potential hole that could sink it in a matter of minutes. They are usually out of sight and difficult to get to, yet thru hulls need careful routine checking and maintainence. Many thru hulls such as engine-cooling intakes and sink or cockpit drains tend to be left open perpetually and their valves may freeze in the open position due to corrosion or build up. They should be operated regularly by opening and closing it to make sure that if an attached hose fails the water flow can be stopped.

Titanium thru hulls are finally catching on and as they become widespread, vessel loss due to thru hull corrosion failure will become a thing of the past.

If you need a thru hull configuration that you don't see in our product list, feel free to call us.