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Seacock 1" Flush, Straight Hose Barb

Part #: Z3646
This 1" raw water engine intake seacock with straight hose barb became standard equipment on many Catalinas towards the end of 1993. Upgrade your existing seacock to this straight barb version for easier clearing of debris from the intake. The flush style thru-hull reduces drag.

Molded Marelon offers superior strength and corrosion resistance. Marelon is lightweight, corrosion and electrolysis free, ideal for thru-hull valves. Marelon is a modern material formulation of polymer composite compounds that uses resins and additives to produce an extremely strong marine-grade product that will not deteriorate like traditional bronze marine plumbing parts. Ideal for above and below the waterline applications.

For emergency service:
Remove the attached white plug covering the screw at the axis of the rotation of the handle. Fasten it to a lanyard. Plug the intake from the outside of the boat. After servicing the valve, use the lanyard to dislodge the plug and bring it aboard to be be stowed on the valve for its next use.
Known usage: (there many have been others):
• Catalina 36: Engine raw water intake
• Catalina 375: Engine raw water intake
• Catalina 400: Aft macerator discharge
• Catalina 470: Forward macerator discharge

A potential upgrade to a much stronger seacock style valve aboard...
Use your discretion to match correct size/configuration:

Boats with early brass pipe nipple through hull:
• Catalina 27
• Catalina 30
• Catalina 38

Boats with early through hull + ball valve installation:
• Catalina 27
• Catalina 28
• Catalina 30
• Catalina 34
• Catalina 36
• Catalina 38
• Catalina 42
• Valve configuration: 1" straight hose barb
• Height from base to top of handle when valve is open (maximum height not including wood mounting ring): 6-3/16"
• King nut diameter: 3-3/4"
• Thru-hull minor diameter: 1-11/16"
• Thru-hull major diameter: 2-3/16"
• Thru-hull outside diameter: ~1-5/8"
• Thru-hull inside diameter: 1-1/16"
• Thru-hull length overall: 2-15/16"
• Thread type: Buttress

The thru-hull uses a buttress style thread with 45 degree angled threads for exceptional strength and are not compatible with any other valves. A buttress thread design with the same amount of clearance as for a conventional pipe thread will give the impression of greater looseness. However, when the joint is taken up tight, there is a greater area of surface between threads with the buttress thread form creating greater load capacity. Like any threaded pipe assembly thread compound or common PTFE pipe sealing tape applied to the threads to seal is required.
1) Catalina often used a 3/4" valve with a Female Pipe Thread (FPT) at the top. They then added adapters to the top 3/4" FPT to fit a 1" ID hose for applications such as the galley sink drain.

2) To determine the size used of valve used in your boat you must remove the hose from the top of the valve. Inspect the top of the valve carefully. Is the hose barb a 1" diameter and an integral part of the valve as shown in the photo? Or is a hose barb and adapter screwed into the top of the valve? If the hose barb is separate from the valve, you likely have a 3/4" valve, part #Z3919. Compare to the table found in the article below in "Technical Support" to be certain of the size of your valve. Do not assume that you have a 1" valve just because you have a 1" hose

2) Each valve is factory assembled and pressure tested. We cannot be responsible for valves disassembled and modified or reassembled improperly.

The buttress thread on these seacocks is not compatible with and will not work with a traditional through hull thread type. The seacock and through hull fitting must be replaced in sets at the same time.

Technical Support

Pipe Sizes and Why They Are So Confusing
Why doesn't my 3/8" NPT fitting measure 3/8"?