Sea cock replacement

[VirgoVoyager]

The sea cock on the toilet inlet on our Virgo Voyager has ceased to be. The handle turns, but there is no one at home. Anyone got any advice on replacing defunct sea cocks? I am assuming that we will have to drop the old girl on her bilge keels, but any further thoughts, experience etc would be most welcome.

Stuart

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[beneteau_305_553]

I replaced mine this year.

grind off the flange on the outside. Trying to remove the old back nut was impossible. Fit new skin fitting and new ball valve. I used bronze skin fitting but I have been told that the plastic ones are as good if not better and much chaeper. Seal to the hull using sikkaflex 221 or similar polyurethane sealant.



<hr width=100% size=1>Richard

 

[Abigail]

Echo that - we just did 6!! Don't try and get away without replacing skin fitting as just not worth it. When I asked this forum about plastic/delrin for seacocks I got told it was a daft idea, and further examination of the costs has meant we have gone with bronze.

There was an excellent article in this months Cruising World on the topic, which sadly they havn't (yet?) put on line, but you could always contact them via www.cruisingworld.com and see if they will post it or even send it to you.

<hr width=100% size=1>Sarah&Pip

 

[alahol2]

Further to this...
Is there a reason why inlet valves always seem to be these awful gate valves with rusty wheels, that seem to fail after a few years, whereas the outlets are usually Blakes seacocks that go on for centuries? Is it purely down to cost, or am I missing something?

<hr width=100% size=1><A target="_blank" HREF=http://www.troppo.co.uk/tightwad/tightwad.htm>http://www.troppo.co.uk/tightwad/tightwad.htm</A>

 

[AndrewB]

Brass is a particularly bad idea on the heads outlet as urine promotes rapid dezincing.

Brass (including zinc-, manganese- or commercial bronze) gate valves are not only cheap but relatively small, makes them easier to fit in confined spaces. They always have a limited life-span - the usual way they fail is through stripping of the central screw-thread. Often they get so they won't fully close. So they need periodic dismantling, inspection and servicing. Some grades of brass are much better than others. Avoid those made in Italy or China: a giveaway of low quality is they have a pressed mild steel handle (hence the rust) rather than a cast brass one. A minor advantage is that they generally come off reasonably easily, and so do not require a new skin-fitting each time they are replaced, provided the latter is decent phosphor-bronze or similar. As Abigail says, brass skin fittings must also be replaced regularly, as they also dezinc and weaken. I'm anti the plastic ones below the water line after I saw one cracked right across, but of course they are widely used.

 

[VirgoVoyager]

Thanks, guys, for all the helpful advice - I will take a deep breath and go for replacing the whole shooting match!

Stuart

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[DogStar]

Just thought I'd point out what someone told me when I thought I might have to replace a seized seacock. They said don't just dry out for a tide. Wait until you are getting the boat out of the water anyway. Just in case anything goes wrong and you can't finish the job in less than 6 hours. Sorry if I'm teaching granny to suck eggs!

<hr width=100% size=1>I'd rather have a bottle in front of me than a frontal lobotomy!