Hose Clamps, Seacocks & Thru-hulls, Heads, Holding Tanks and Sanitation

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Postby stephenj » Mon Jun 30, 2014 9:36 pm

I have a 38 Telstar 1985, Anyone have any idea what the thread on original the seacox is e.g. BSP or NPT ??
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Joined: Wed Nov 13, 2013 3:46 pm

Re: Seacox

Postby scleary » Tue Aug 05, 2014 2:02 am

I can't comment on the 38, but I can tell you the 43T has BPT threads on the thru-hulls for the scuppers. I just replaced with NPS/NPT parts.

I had a bad gate valve, labeled 2-1/2" and only thinking metric/standard I foolishly bought a new 2-1/2 NPT gate valve and very quickly realized it was 2-1/2" BPT on the old valve. Since finding a BPT valve would be problematic, I opted to replace all of the other associated parts, the 2-1/2" BPT to hose barb 90, and the thru-hull which was 2-1/2" british (straight I would bet, BSPP) as well. I replaced with an NPT to NPSM adapter. The thru-hulls are all NPSM, the valves are all NPT, the adapter takes straight thread on one side and pipe thread on the other. It is the 'base' of the very expensive 'all in one' sea-cocks you see with the triangle of 3 mounting holes and a ground screw, female NPSM on the bottom, male NPT on the top.

It's worth mentioning that the original BPT to hose barb 90 looked fine, but I pushed my fingernail right through it on the barb portion. Not sure if it was just low quality to start or if it has worn thin over time.
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