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Seacock 3/4" Flush, 3/4" FPT

Part #: Z3919
This seacock with 3/4" female pipe threads on top became standard equipment on many Catalinas towards the end of 1993. Typical uses are for the macerator discharge or for the galley sink drains. Includes a flush style thru-hull fitting. See "May we also suggest" below should you need the mushroom style thru hull fitting.

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.
Known usage: (there many have been others):
• Catalina 28: Galley sink drain
• Catalina 310: Macerator discharge (early models)
• Catalina 320: (5) total on early models, (2) called out on later boats
• Catalina 34: (2) total, (1) macerator discharge, (1) galley sink drain
• Catalina 36: (2) total, (1) macerator discharge, (1) galley sink drain
• Catalina 42 (all models): (3) total, (2) for macerator discharge, (1) galley sink drain

*Note: Often Catalina used this 3/4" valve and added adapters to the top 3/4" FPT depending upon the application. For example, a common adapter was an elbow with a 3/4" MPT to a 1" hose barb. A 1" ID hose was then connected between the elbow and the 1" port on the macerator pump or the galley sink drain. To determine the size used in your boat you must remove the male pipe thread adapter and measure. Compare to the table found in the article below in "Technical Support" to be certain of the size of your valve.
• Valve configuration: 3/4" Female National Pipe Straight Mechanical (NPSM) threads
• Height from base to top of handle when valve is open (maximum height not including wood mounting ring): 4-1/2"
• King nut diameter: 3-1/8"
• Thru-hull minor diameter: 1-9/32"
• Thru-hull major diameter: 1-23/32"
• Thru-hull outside diameter: 1-3/32"
• Thru-hull inside diameter: 5/8"
• Thru-hull length overall: 3"
• 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 Teflon tape applied to the threads to seal is required.
1) If your through hull has a mushroom through hull and it needs to be replaced as well, order Thru Hull Mushroom for 1/2" or 3/4" Seacock listed below in "May we also suggest".
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"?