Seacock Problem

[dignity]

When leaving the boat last night I attempted to close the toilet seacock, kept turning the valve but nothing appears to be happening it just turns and turns, also if turned anti-clock wise the handle shaft seemed to be worming it's way out, does anybody know how the internal mechanism works in a seacock can it be fixed, or more to the point is it possible for the seacock to leak through the tap?

I hope you can understand what I've tried to explain, any thoughts would be appreciated because I'm quite concerned that it may start leaking?

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[drawp]

Is the valve part of the toilet pump or is it an actual seacock on the hull. Do you have the valve manufacturere's name and the model number?

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[dignity]

It's the actual through hull skin fitting

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[philip_stevens]

If it is the gate valve type, I think I can explain what has happened - I have even got my gate valve, that had to be replaced last week.

On the spindle of the gate valve shaft, there is - or should be - a small flange, that sits between the body of the top section, and the packing. If (as with mine) the flange has worn away, you get just what you have got - the spindle/handle just keeps turning, but nothing happens to the gate.

The lower part of the spindle has a very course thread that goes into the gate. What you have, is that the thread is going into the gate, but as the flange has gone, there is nothing for the spindle to push against.

If this is what the problem is, then the only suggestion I have, is to replace the gate valve with a bronze ball valve - as I did last weekend on all three gate valves: galley and heads sinks, and engine cooling water inlet.

<hr width=100% size=1>regards,
Philip

 

[dignity]

Thanks for that, what I'm concerned about is should the spindle remain watertight because the valve is stuck open, it's going to be about a month before I can have the boat lifted.

Putting the question more straight forward what seals the spindle?

Sorry if that question sounds daft question, just a bit nervous when it comes to seacocks.

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[AndrewB]

The gate screw stripping won't actually cause the seacock to leak through the handle - but it isn't working either. (However a lot of cheap gate type seacocks tend to leak slowly through the handle anyway). Either the gate is now permanently shut, in which case your heads are out of action, or its permanently open, in which case a leak in the outlet pipe could well sink your yacht.

Brass gate valves are particularly vulnerable when used as heads outlets, because urine hastens the disintegration of the the brass (dezincification, the zinc is removed by electrolytic action).

If the gate is open, get this fixed ASAP, and keep very careful watch on the boat in the meantime. If it's shut, it is not quite so urgent. If for any reason you are obliged to fit another brass gate valve - and it's certainly best not to - make sure it is best quality: look for a solid, not a pressed handle and avoid those made in Italy. Remember that it ought to be stripped down and checked every year, and is unlikely to last more than 4.

 

[dignity]

Thanks for that advice, I'm thinking of doing away with the sea-toilets and fitting chemical ones instead, when the boat comes out I'll fit new skin fittings and blanking devices, which I presume you can buy.

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[Trevethan]

In the meantime, I suggest banging a softwood plug into the skin fitting from the outside, just in case.

I you are serious about replacing the whole fitting, even better is epoxy putty that goes off under water.

I had a similar problem with a gatevaleve that more or less disolved and was left open.

I packed the fitting with plastic then smoothed a a couple of sticks of the stuff inside the fitting to make a plug, while i waited for a lift out. It held well for the month or so I had to wait to get lifted and replaced with a lovely ball valve..

regards,

Nick

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[philwebb]

Hi Dignity,
You could replace your gate valve seacock with a ball type lever action
valve. You will be able to get one of these from a plumbers merchant, or from a mail
order plumbing supplier such as BES. These are more reliable than the gate valves and
give a more positive cutoff. You could dry your boat out on a scrubbing grid to change the valve. You may find that you have to replace the skin fitting at the same time, if it
is corroded. To remove this you will need an assistant on the outside. It will have two
notches on the inside and the assistant will have to push something into it to stop it
from turning while you turn the nut on the inside with a wrench. Not difficult . Use
sikaflex to seal the fitting to the hull, use PTFE plumbing tape to seal the valve to the
skin fitting.
If you have nowhere to dry the boat out you could resort to putting on a wetsuit and
putting a wooden wedge or a rubber stopper in the skin fitting from the outside before
removing your gatevalve, but you would have to be careful that the skin fitting did not
turn while you were removing and replacing the valve.
Regards,Phil

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