Buying used seacoks? How do I vet the?

[esarratt]

I need new seacocks for my boat. I am cheap when I can get away with it. I was thinking of shopping for used Blakes, Wilcox or Spartan seacocks.

Then it dawned on me, what if they have micro cracks?

Is there anyway to carefully examine a bronze seacock and determine if the metal is sound? I don't want to install it to find out that it has a hairline crack when under pressure.

Can I use dye penetrant testing to find cracks in bronze? Or can I use a jewlers loop?

Your thoughts and suggestions are appreciated.

[Pete7]

How many are we talking about? can't be that many on a 24ft yacht surely. If so then fit TruDesign (glass re-enforced nylon composite) and be done with it.

https://shop.tnorrismarine.co.uk/collections/trudesign

We are slowly working our way around the yacht doing them.

[Chotu]

I have some top of the line, unused, still in the original boxes, Groco sea cocks I’m looking to sell soon. They are not going to be too cheap, but definitely less than retail

[esarratt]

Originally Posted by Pete7

How many are we talking about? can't be that many on a 24ft yacht surely.

Four total.

Yes, I have thought about the glass filled nylon. Here we have marelon which I have considered.

Thank you.

[tkeithlu]

Yes, you can dye test bronze, yes, Maralon is a good idea, no, a loupe would keep you busy with no guarantees.

[Compass790]

Can't comment on yr brands but dye pen aint bad for testing.
If bronze has pinkish hue run a mile.


Much rather have FRP seacocks anyday.
FWIW Grizzled old boatbuilder ( over 70 ) who had slipway next to club slipway told me he had far less problems with plastic seacocks than metal.

[S/V Illusion]

I’m all for saving money when there is a choice, however, securing 4 holes in the hull below the WL isn’t the place. How much could you possibly save for the potential failure risk?

[esarratt]

Originally Posted by Compass790

If bronze has pinkish hue run a mile.

Thank you!

Originally Posted by Compass790

FWIW Grizzled old boatbuilder ( over 70 ) who had slipway next to club slipway told me he had far less problems with plastic seacocks than metal.

Interesting. That was useful anecdotal information.

[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

[George DuBose]

I have had great luck with my 50 year old Wilcox-Crittenden seacocks. When Skylark came to me, all the seacocks were frozen, but after grinding off the flanges of the thruhulls, I was able to remove all of them, put them in an auto parts washer, disassemble them, clean them up with a wire brush on a bench grinder.

When my wife (the Admiral) saw them installed, she asked me if they were new. I told that I had them gold plated to prevent corrosion.

Really had her going...

Working them regularly, greasing them annually, they will last longer than me.

[bcboomer]

I've had bronze, Marelon and now Trudesign.
Trudesign is the best by far. No concerns about corrosion like you do with bronze and they never stick like Marelon do. I'm sure they are available where you are.

[joelhemington]

Originally Posted by S/V Illusion

I’m all for saving money when there is a choice, however, securing 4 holes in the hull below the WL isn’t the place. How much could you possibly save for the potential failure risk?

Yep seems like an egregious job to me as sea cocks are usually not that accessible. I think I'd drop the change on new bronze ones and be done with it.

[Clivevon]

In all sorts of different contexts, your dilemma is as old as mankind. So old that the ancients have codified their recommended solutions thus:
“Penny wise, pound foolish”; “dont spoil the ship for a ha’porth of tar”; “buy cheap, buy twice”; etc, etc.
I replaced all 11 of my seacocks (yeah, i know, worries me a bit too) with Trudesign ones 6 years ago. No issues since.
You will not get cheap used Blakes seacocks unless you are very lucky & they will likely need a lot of attention. The point with Blakes is that you can refurbish them & of course they are top quality bronze to limit your corrosion worries. They were the best in their day no doubt.
But Trudesign seacocks have zero corrosion issues & are not that expensive, surely. You only need 4. Buy them, fit them properly, & move on, would be my advice.

[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.

[Cadence]

Originally Posted by esarratt

I need new seacocks for my boat. I am cheap when I can get away with it. I was thinking of shopping for used Blakes, Wilcox or Spartan seacocks.

Then it dawned on me, what if they have micro cracks?

Is there anyway to carefully examine a bronze seacock and determine if the metal is sound? I don't want to install it to find out that it has a hairline crack when under pressure.

Can I use dye penetrant testing to find cracks in bronze? Or can I use a jewlers loop?

Your thoughts and suggestions are appreciated.

Why replace used with used and unknown? They had been replaced for a reason. JMHO