Seacock Identification

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ERTF

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Anybody have a seacock identical to the one in the picture? It's on an 1989 Marine Trader and quite possibly is original, but I'm not sure.

Hard to see with the corrosion, but the narrow section between the seacock and the flange is a hex shape. I tried scraping with a pick tool between the flange and hex / cock and hex, but cant see any crevice.

My hope is that it is like the diagram with the seacock being able to be threaded off while leaving the nut/flange in place. But not seeing any crevice makes me hesitant to put a wrench to it while in the water incase it is all one solid unit from seacock to the flange.

This seacock was buried back in a basically inaccesable location next to the fuel tank I cut out. It is an exit for a shower sump that is stupidly just below the waterline like every exit thru hull on this boat. Once out of the water I plan to move them all up. But for now I am trying to install a slightly longer fuel tank and i need that seacock removed. My thought was for now to remove the seacock (if possible) and just put a cap on the thru hull.

Anybody have the same unit?
 

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The photo and diagram don't seem to be the same unless the seacock in the photo is inverted.
It is likely female threaded and the hex nut may be there to lock it into position.
I would really scrub it with cleaner and soak it with penetrant before doing any work.
Maybe start by seeing if there are threads below the hex and gently try to loosen it.
Another note: the thru-hull may be straight threaded and that may affect how a cap seals.
 
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On the thru hull it says "555 WOG". No record of that when googling. Adds to my theory that it is probably original. Also the thru hull next to it has the same markings.

Both hex's on the one I want removed look to be aligned. However on the other one (of the same brand) I notice that the hex's are not alinged, so that is some evidence that it may not be one solid unit.
 
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KnotYet said:
Another note: the thru-hull may be straight threaded and that may affect how a cap seals.
Click to expand...
I wondered about that. How common is it to come across a thru hull that is not NPT? Especially a 35y/o one from Taiwan?

I figure I could pound a short bung into the outside, then fill it with epoxy from inside if i have to. Or see if i can shift enough weight to heel my boat over so its completely above the waterline. Then dry it out and force thickened epoxy all the way thru it so it has a mushroom on each side.
 
This is opinion, based on what I see in the pictures, not personal experience with your model of boat.
That looks like a standard ball valve, not a proper seacock.
As mentioned, the skin fitting will have straight threads, and that valve has tapered threads. That’s why the valve is threaded so far onto the threads, they didn’t lock up on a taper.
That said, I have capped a skin fitting with a standard bronze pipe cap, but I plugged the fitting with a wooden plug first, then used 5200 on the threads for sealing.
I only used the 5200 as I was abandoning the through hull forever.
If I were to remove it later and glass over, the wooden plug gives a center for the hole saw I’d use to remove the fitting.
 
It was all one piece.

That's about 9/32" of threads sticking out. Is that enough to get a cap on? Is it likely straight thread (or npt)?
 

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ERTF said:
It was all one piece.

That's about 9/32" of threads sticking out. Is that enough to get a cap on? Is it likely straight thread (or npt)?
Click to expand...
That's not a lot. Guessing straight but with so little engagement that's not a big deal.
Perhaps a NPT pipe cap could be used, even shortened to make it fit more snugly.
Is it possible that any of the through-hull's threads remained inside the ball valve?
I agree with Bmarler that looks like a ball valve rather than a seacock.
 
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as mentioned probably doesn't matter tapered or straight with so few threads available. i'd try fitting a cap and see how it feels. i think knotyet has a good point about a shortened cap for better engagement. taking off a few of the bigger od threads will make a tighter fit.
 
Greetings,
Mr. E. IF that fitting will be covered by your larger fuel tank I strongly suggest you remove it completely and properly fill the hole. Any cap you might put on can come back and bite you at the worst time.
 
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