Buying used seacoks? How do I vet the?

[stormalong]

Originally Posted by Manateeman

Worse mistake I made in 50 years of boatbuilding was plastic seacocks. I’ll have a bunch of Forespar seacocks to give away to anyone who wants to practice sinking drills.
Groco. Period.
Happy trails to you.
Captain Mark and his professional boatbuilder manatees

Manateeman: I have seen your response before. I am speculating that your experience is from a long time ago. I have Marelon seacocks in my 35 Y.O. boat, some original, some replaced. Never has a catastrophic failure. Worst case they wouldn't operate. Some replaced because they were not the newer flange mount type and I thought they were vulnerable.

So, what sizes are these free Marelon seacocks and how do I get them?

[ussvdharma]

Sea cocks have a finite life expectancy....I would not trust a used on to my boat...could be wrong, but that is what I think. Lots of used items on my boat but not sea cocks. De W7KFI

[Lepke]

Seacocks, properly protected and cared for, should last the life of any boat. My current boat, built in 1942, still has many original seacocks. Used seacocks are no different that ones removed for routine inspection. In my time in yards, I saw many fine seacocks and other thru hulls removed for no good reason. I acquired most of them, and they're still serving in other boats.
IMO yachties are like sheep, especially the ones with more money to spend, will change out seacocks for no more reason than the seacocks are no longer shiny. Once one does it, they all gotta do it. Great for the yard business.

[esarratt]

Oh Lordy. I didn't realize there were such strong feelings about plastic (Marelon/Nylon) vs bronze seacocks.

Interesting. I'm afraid I have poked the bear.

[esarratt]

Originally Posted by chasmains

Being in the mechanical side of the nuclear industry and nuclear Navy, I can give you testing procedures for pressure components if you want.
Also, I did liquid penetrant inspections. I wouldn’t do that with valves. Most valve bodies are cast. The problem is there is a lot of surface imperfections on castings. This means you cannot clean off excess penetrant well enough to guarantee a good valve body. Cracks will indicate, if any. But many of the imperfections will bleed out too, giving you false information showing a crack where ther isn’t one.
My approach would be to find a way to pressure test each valve. The pressure side MUST be the water side. So a valve not having a way to seal the water side to pressurize cannot likely be tested. If they can be, then air or water can be used to test. (Air testing is pneumatic testing and water is hydrostatic testing.). Water leaks are easy to see. Air leaks often require a soap test solution that you can make are home. Test only to 2x or 3x the max water depth pressure. No sense in over-pressurizing the valve and killing it. Our thumb rule in the Submarine is 44 psi per 100 feet water depth. So 4.4 psi per 10 feet water depth. Calculate the max water depth of the valve in all heel conditions. Multiply by 3 and then test to that pressure. Hold pressure for 10 or 15 minutes. If a leak, the gauge will indicate and the valve will show leaking fluid.

I never thought about that. That is easy. I actually have a leak down tester.

[esarratt]

Originally Posted by Clivevon

“Penny wise, pound foolish”; “dont spoil the ship for a ha’porth of tar”; “buy cheap, buy twice”; etc, etc.

Yep. I knew this would be pointed out. 1.5" Blakes seacocks are $251.34 shipped to the US. So, four would be just over a grand. Not too bad.

1.5" Spartans are $406. Ugh!

[Fore and Aft]

Good question, I noticed there are some cheap Groco seacocks that are four years old in Miami on Craigslist. They might be ok, Dugongman loves them so they must be good. I would not be surprised if they were only replaced for a silly reason? I have a lot of clients who do not muck around and just like everything to be new at the same time. So instead of just replacing one faulty seacock they replace the whole lot and sleep easy knowing everything below the waterline is new.
Cheers

[Cadence]

I can see going cheap on somethings, holes in my hull is not one. I would hate to have the feeling was a used seacock good or not.

[bcboomer]

Originally Posted by esarratt

Yep. I knew this would be pointed out. 1.5" Blakes seacocks are $251.34 shipped to the US. So, four would be just over a grand. Not too bad.

1.5" Spartans are $406. Ugh!

Trudesign $154.99 and free freight

https://www.fisheriessupply.com/rari...seacock-valves