Marine Thru-Hulls & Drains for Boat Plumbing
Marine thru-hulls and drains provide secure passage points for water intake, discharge, cockpit drainage, and other onboard plumbing functions. CritPro carries durable hull fittings for recreational and commercial vessels as part of our complete Thru-Hulls, Seacocks & Strainers selection.
What to Look for in Thru-Hulls & Drains
Select fittings based on hull material, connection size, hose diameter, thread type, mounting angle, and whether the component is installed above or below the waterline. Marine-grade bronze, stainless steel, and composite materials provide dependable corrosion resistance.
What Happens Downstream of the Thru-Hull
A thru-hull is the opening. What passes through it is the part that determines whether the equipment on the other end survives. Weeds, shells, silt, and plastic all enter a raw water intake, and anything that gets past the strainer reaches the pump impeller and the heat exchanger next. A strainer basket is the cheapest component in that chain and the one that protects the most expensive ones.
Baskets are consumable service items. They corrode, deform, and eventually split, and a basket with a hole in it is worse than no basket at all because it looks like protection while passing debris straight through. Pull yours at haul-out and hold it up to the light. The GROCO 1.25-Inch Fresh Water Strainer Basket in stainless steel is a replacement element for compatible GROCO strainers, built for repeated water service and removable for routine cleaning and inspection.
Fitment is the part to get right before ordering. Strainer families and housing sizes use different basket diameters, lengths, and seating arrangements, so verify the strainer model and basket dimensions rather than ordering by nominal pipe size alone. When servicing, isolate and drain the water circuit first.
What This Category Covers
This category includes bronze and stainless steel thru-hulls, hose-barb fittings, scoop thru-hulls, deck drains, cockpit drains, scuppers, hull strainers, replacement strainer baskets, clam-shell vents, and related drainage hardware.
Complete Your Hull Plumbing Installation
Pair your fittings with Seacocks & Ball Valves, protect water intakes with Raw Water Strainers, or explore our complete Marine Plumbing department.
Browse our complete selection of Marine Thru-Hulls & Drains at CritPro.