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Thru-Hull Flush for 1/2" or 3/4" Seacock

Part #: Z5063
Flush through hull portion of the 1/2" and 3/4" seacock through hull valves used on most Catalinas 25' and larger starting in 1993. This part is only for the white through hull portion of the seacock.

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 310: (2) total, (1) shower sump, (1) galley sink drain
• Catalina 315: (3) total, (1) engine raw water intake, (1) galley sink drain, (1) macerator
• Catalina 320: TBA (2 total per valve kit)
• Catalina 34: Head sink drain
• Catalina 350: Head sink drain
• Catalina 355: (4) total, (1) engine raw water intake, (1) AC circulation pump, (1) head sink drain, (1) shower drain
• Catalina 375: Head sink drain
• Catalina 380: Head sink drain
• Catalina 385: (2) total, (1) head sink drain, (1) shower drain
• Catalina 387: Head sink drain
• Catalina 390: Head intake
• Catalina 400: (2) total, (1) fwd head sink drain, (1) aft head sink drain
• Catalina 440: TBA (2 listed per valve kit)
• Catalina 445: (3) total, (1) AC Circulation pump, (1) aft sink drain, (1) shower sump drain
• Catalina 470: Fwd head intake
• 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"

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.

Technical Support

Through Hull Evolution - Caution Vintage Catalina Owners!
To change or not to change? Don't let that question keep you up at night, but pray it is not water waking you in the morning.
Pipe Sizes and Why They Are So Confusing
Why doesn't my 3/8" NPT fitting measure 3/8"?