In the drainage systems of ships, yachts or campers, the thru-hull outlets are an unobtrusive but crucial component. They can safely discharge bilge water, sinker basin water or air conditioning condensate out of the hull.
These three types of thru-hull in this article: the thru-hull with hose, the 90-degree half-filament bend outlet, and the thru-hull with check valve, can be respectively applied to different drainage scenarios.
Type 1: Thru-hull with hose
This type of thru-hull outlet has the simplest structure. Its water inlet end is equipped with a half-thread and a hose connection, while the thru-hull outlet end is a straight opening.This type is suitable for areas where the hull space is ample and the drainage path does not have any bends.
Applicable scenarios: Bathtub, small bilge pump, air conditioning condensate water.
Type 2: 90-Degree half-filament bend outlet
The drainage pipes of many small yachts’ bathrooms are very close to the hull. Using a straight outlet would force the hose to make a sharp turn, which is prone to getting clogged. Switching to a 90-degree half-filament bend outlet allows the hose to be connected smoothly and the water flow to be more unobstructed.
Applicable scenarios: Situations where the interior space of the vessel is narrow and where pipelines need to be laid close to the hull.
Type 3: Thru-hull with check valve
As long as the thru-hull outlet may be submerged underwater, a thru-hull with a check valve must be used. Otherwise, waves or water pressure during navigation will push seawater back into the cabin.
Applicable scenarios: Locations where the thru-hull outlet is below the waterline, such as the drainage outlet of the bottom pump on large yachts, or the discharge outlet for ballast water.
Material combination: Stainless steel + Nylon, balancing strength and corrosion resistance.
The stainless steel parts are made of 316 stainless steel. This material is resistant to salt fog corrosion and is suitable for long-term exposure in marine environments.The nylon part is lightweight, corrosion-resistant, and provides better sealing when connected to the hose.
In summary, whether for routine drainage or extreme conditions, Alastin’s three types of thru-hull outlet designs cover all scenarios from the upper deck height to below the waterline.If you would like to know more about the technical parameters or get selection suggestions, please feel free to contact our sales team.
Post time: Apr-10-2026