Replacing Ball Valves Without Replacing Skin Fittings -- Bad Practice?

[jgbrown]

RE&Re the skin fittings to re-seal them. I'd replace and never think about them again myself but at least pull and replace them with fresh sealant, 17 years between re-sealing is a pretty good run, unless you get hauled out and blocked for free and are paying someone by the hour for the job. It'd be pretty frustrating to pay for a launch and then pay for a haul again because one is leaking. If there is a thread mismatch, replace for sure(not a problem in your case though), by the time you buy ball valves, build backing plates and install flanged adapters you may as well do the skin fitting too and just be done with it.
I like Permatex high temp PTFE sealant, has a nice dispenser nozzle and is useful for pretty much everything thread sealing related(except propane of course) a tube will last you years, and never goes bouncing along the bilge unrolling itself like tape does. Easier than mucking about with tape in confined spaces too. Don't use both, one or the other whichever you choose. It's half for assembly lubrication and half for sealing.

[Dockhead]

Originally Posted by Kenomac

Change them, then you’ll know what they’re made from. Right now... you don’t know for certain.

Well, but I do know what they are made of (gunmetal bronze) , and who made them - they are all original Moody fitment.

[Dockhead]

Originally Posted by Wotname

As for replacing the skin fittings, my take is these should inspected regularly (as DH is doing) and replaced on condition rather than time in service.

However if one's wallet is deep enough and one is sure that the replacement item is the same as (or better than) the original, then go for it.

I wouldn't mind spending the money on skin fittings, but installing them is pretty laborious, and I'm trying to get back into the water and such a job would really stress the work schedule - coming on top of a number of unexpected jobs like cutless bearing and stripping the keel to bare metal. I just had an eminent local surveyor glance at them, and he shares the opinion of most of you here that they are ok for further service.

[Dockhead]

Originally Posted by deblen

Groco flanged adapter plate.

https://marinehowto.com/seacock-thru-hull-primer/

Not applicable as we have all BSP threaded hardware.

[Dockhead]

Originally Posted by malbert73

Just out of curiosity how do you lubricate them and what do you use?

Waterproof white marine grease. I daub it in through the skin fitting with a foam paint brush, onto the ball, then work the valve.

[Dockhead]

Originally Posted by terah

My understanding is that pinking is an issue with brass; the dezincification leaves behind copper which appears pink. So if your through hulls really are bronze (or DZR brass) I'd be tempted to leave them.

Mine unfortunately (and thanks to the barmy RCD requirement of them only needing a service life of 5 years) are brass, so will be replacing the lot.

Had they not been brass I was considering fitting TruDesign ball valves to the existing through hulls.

Only thing is to be very careful not to disturb the seal of the through hull while removing the ball valve.

Indeed.

Mine all popped right off without any problem. If the skin fitting doesn't stay put when you do this, then it needs to be rebedded, in my opinion, so I don't hold them when twisting off the valves. Intentional stress test.

[stormalong]

Originally Posted by a64pilot

Good point, assuming both are straight threads then Loctite and not pipe dope or tape ought to be the preferred substance.
Although I doubt there would be any leakage anyway.
Perhaps purple “low strength” or green “wicking” would be best?
Even blue over that size of threads would be tough to remove.

I’d be tempted to put it all together, then apply the green to the assembled joint myself.

Never use locktite for this purpose. It requires heat above 400 degrees Fahrenheit to remove. Do you really want a blowtorch in your bilge?

As for through hull sealant use 3M 5200. I know this will start a heated discussion but it will hold the through hull from spinning and yes, it will be a pain to remove but it will not fail. I have had 5200 sealant in my Marelon through hull fittings since the boat was built. When I went to change one after 20 years to put on a strainer both the Marelon and the sealant were as good as new.

As for replacing through hulls so that you know what material they are made of don't be too sure. Just because they are new does not mean that the alloy is correct. That is the main reason I like Marelon - no potential for electrolysis.

I have thirteen Marelon seacocks in my 32 Y.O. boat. About two thirds of them original and they all work fine.

[iseadreamer]

We replaced all the gate valves with ball valves in 1997; leaving Morgan's original skin fittings. We use CRC Corrosion Control in and out every year on haul out and have had zero issues with either corrosion or valve sticking.

[Cadence]

Originally Posted by Dockhead

I'm changing a bunch of sea cocks on my boat. Some of them are original to the build, so 17 years old. Others were changed 7 or 8 years.

I changed the previous ones because they were frozen and/or shaft broken -- neglect by the previous owner. But I exercise and lubricate my sea cocks, and always turn them off when I leave the boat overnight, so the rest of them have not suffered from this problem. I've had some external green corrosion but the bronze has otherwise held up just fine. I have tested them in different places and there is no pink.

However, my bilges are damp (keel stepped mast) and the f-ng handles of these ball valves are plated mild steel! They eventually rust, and the shafts are steel too and rust . I have bought new bronze ball valves made in Italy with stainless handles and bronze shafts and plated bronze balls.

Here is my question -- is it bad practice to replace the ball valves without replacing the skin fittings?

My skin fittings seem to be absolutely fine -- not the slightest pink color anywhere. I have wire brushed them and checked them everywhere. They have remained well bedded in their places and I don't see any reason to change them.

What say ye?

Why not replace them now so you know everything is good and you will probably never have to do it again. I'm assuming skin fittings are through hulls this side of the pond.

[S/V Alchemy]

Originally Posted by GordMay

If you see no reason to change them, I doubt I would either.

I would qualify that by checking the make to ensure they are correct alloy of bronze. Some newer fittings coming out of the EU look like pink (potentially) garbage.

So I gather the idea is to leave the seacocks open and to use short lengths of hose to the new ball valve, which you could close? I just did this, but on a steel boat. I simply welded an SS pipe nipple (NPS threaded) to take a Marelon ball valve. Double-clamped AWABs on the shortest piece of hose I've ever dealt with!

But in terms of function, that sounds like what you want to do.

[Dockhead]

Originally Posted by Cadence

Why not replace them now so you know everything is good and you will probably never have to do it again. I'm assuming skin fittings are through hulls this side of the pond.

If I had time, I would -- the cost would be a drop in the bucket in the context of this refit, which is costing me $30k -- $40k.

The problem is time -- no engineers available, so I'm doing the work myself with an unskilled helper, and we just don't have time for the laborious work of removing skin fittings (yes, through hulls), rebedding new ones, etc., etc. etc. on top of everything else. We have a list of things to do running to four pages and we just can't get sucked into a major job on sea cocks which are mostly quite all right.

As always it is taking twice as long as I imagined with some wrong parts ordered , and as usual what was supposed to be 3 sea cocks turned into 5 and now has turned into 7 , so like most boat jobs this has mushroomed despite our intention to get this done quickly in order to get on with other jobs

The "bangheads" are mostly kidding; I enjoy getting away from my desk job to turn a wrench. I've been fixing boats and cars long enough to know how these jobs always go.

And the most enjoyable thing of all is seeing the gleaming new ball valves with their lovely stainless handles shining in the clean bilge where we put them in. That feels good.

[Dockhead]

Originally Posted by S/V Alchemy

I would qualify that by checking the make to ensure they are correct alloy of bronze. Some newer fittings coming out of the EU look like pink (potentially) garbage.

So I gather the idea is to leave the seacocks open and to use short lengths of hose to the new ball valve, which you could close? I just did this, but on a steel boat. I simply welded an SS pipe nipple (NPS threaded) to take a Marelon ball valve. Double-clamped AWABs on the shortest piece of hose I've ever dealt with!

But in terms of function, that sounds like what you want to do.

Well, I'm not changing anything about the original design. Stout bronze skin fittings with BSP threads and backing plates and nuts, and ball valves screwed directly onto them. KISS.

[Cadence]

Originally Posted by Dockhead

If I had time, I would -- the cost would be a drop in the bucket in the context of this refit, which is costing me $30k -- $40k.

The problem is time -- no engineers available, so I'm doing the work myself with an unskilled helper, and we just don't have time for the laborious work of removing skin fittings (yes, through hulls), rebedding new ones, etc., etc. etc. on top of everything else. We have a list of things to do running to four pages and we just can't get sucked into a major job on sea cocks which are mostly quite all right.

As always it is taking twice as long as I imagined with some wrong parts ordered , and as usual what was supposed to be 3 sea cocks turned into 5 and now has turned into 7 , so like most boat jobs this has mushroomed despite our intention to get this done quickly in order to get on with other jobs

The "bangheads" are mostly kidding; I enjoy getting away from my desk job to turn a wrench. I've been fixing boats and cars long enough to know how these jobs always go.

And the most enjoyable thing of all is seeing the gleaming new ball valves with their lovely stainless handles shining in the clean bilge where we put them in. That feels good.

To me giving up the desk job was. I miss the employees/friends.

[sailorchic34]

I suspect the older bronze through hull fittings are superior to the new ones. Reason is many countries are limiting lead in bronze castings and substituting aluminum instead.

Gunmetal bronze use to be 85% bronze, 5% tin, 5% lead and 5% zinc. Newer bronze ingots are replacing the lead with Aluminum. Which means in seawater after the 5% zinc dezinc's the aluminum will go next.

Overly simplistic as there are many different formulations of bronze.

I did have a discussion with Hopcar ages ago about newer bronze. He contacted a manufacturer, who did confirm that they were using aluminum instead of lead in their bronze formulation.

My old spartan seacocks and throughhulls are original (46 years old) and still look very good (no pink at all)

[onavegador]

As I was tired of the oxydation on bronze sea cocks and through hull fittings and after I had for years no problems with glassfiber renforced Nylon Through hulls and seacocks I changed to that also on my, for me new, but very old British catamaran. One more advantage is that you can forget about galvanic damage. The product I bought is branded Truedesign from NZ, they are Bureau Veritas confirmed.
Good luck.
James