Seacocks / PTH fittings

[Capn_Tom]

I received my seacocks and related parts today. The seacocks are Apollo and the PTH fittings are Groco. Both items are lsted as NPT but the adaptors don't screw very far into the seacock (at least not easily). I am reluctant to apply force without some assurances because I don't want to damage the threads. Am I missing something?

[mitiempo]

I'm not sure which fittings you are referring to. The through hull (mushroom) fitting is NPS (straight thread) - not NPT (tapered thread). This link might help.
http://www.pbase.com/mainecruising/seacock_primer
and this one as well.
http://www.pbase.com/mainecruising/replacing_thruhulls

[Rachel]

But, unless they have been changed, the Conbraco/Apollo fittings do have female NPT threads on the "hose" side, into which you put male NPT PTH fittings

I also used the Apollo seacocks with Groco PTH fittings, and I've been trying to remember how far they screwed in. Certainly not all the way - but on the other hand I don't remember it being disquietingly little, either. And somehow I only have photos of them before the PTH connectors were mounted.

Rachel

[mitiempo]

That's correct, straight thread on the through hull side and tapered on the hose side.

[Rachel]

Well, since he was asking about the fit of the Groco PTH fittings, I assumed he was on the "hose" side. Tom, I do remember using a wrench to tighten those. And I don't mean just for the last little bit, but rather for quite a few turns. I did also have some sealant on the threads though, so that probably made it more resistant.

Rachel

[Capn_Tom]

Rachel you are correct I was referring to the pipe to hose fitting. I get about 2 full turns by hand. Since no one has indicated that my understanding of the fittings is incorrect I will proceed.

I am using the red frp material that Rachel used for backing plates. I'm using a Jasper Circle Guide with a spiral router bit which allows me to cut circular backing blocks and cut the hole for the thru hull. This is a great router accessory that I highly reccommend.