Disused sea cock

Nick_H

Nick_H

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www.ybw-boatsforsale.com
If you were planning to stop using a sea cock, and you knew it was going to be quite difficult to access it later, would you be happy to just close it and leave it to seize up, or would you want it removed and the skin fitting blanked off?

I can't see any great reason not to just close it, but i'm interested to hear other opinions.
 
Nick_H said:
If you were planning to stop using a sea cock, and you knew it was going to be quite difficult to access it later, would you be happy to just close it and leave it to seize up, or would you want it removed and the skin fitting blanked off?

I can't see any great reason not to just close it, but i'm interested to hear other opinions.
Click to expand...

close it & cap-off. do not rely on the pipe & closed valve
 
I have sailed around with a redundant one for more than 12 years. I simply closed it and tightened the bolts on the clamp plate so that it can't be opened. It is no more likely to fail than any of the others on the boat.

It might come in useful for something 'one of these days'. :D
 
I'd never leave a sea cock open when I leave a boat for any length of time, I always close mine . If the said valve is no longer req I'd have the hole glassed. In next time the boats out for now I'd close it and cap it off. This year I've lost count how many valves ive fitted with this and anodes I seem to have had a run on them, anodes seem to be wasting away quicker for some reason, maybe down to poorer metal qualities. I've just replaced various valves on a not vey old fairline mainly down to corrosion and not being opened and closed regularly to clean the ball part of the valve from marine growth.
 
volvopaul said:
I'd never leave a sea cock open when I leave a boat for any length of time, I always close mine . If the said valve is no longer req I'd have the hole glassed. In next time the boats out for now I'd close it and cap it off. This year I've lost count how many valves ive fitted with this and anodes I seem to have had a run on them, anodes seem to be wasting away quicker for some reason, maybe down to poorer metal qualities. I've just replaced various valves on a not vey old fairline mainly down to corrosion and not being opened and closed regularly to clean the ball part of the valve from marine growth.
Click to expand...

The background to the question is that the gyro has been installed directly above the sea cock for the fire hose, making it extremely difficult to reach to turn it on/off. I'm obviously not happy to have a sea cock I can't get to in an emergency, so my plan is to have a new one fitted in a more accessible position, but that leaves the problem of what to do with the old one. To blank it off will be near impossible due to the restricted access, so the only option I can think of is to turn it off and leave it, other than craning out the gyro again to get access.

As you say, the concern is galvanic corrosion. I can't see any other way a redundant, permanently closed sea cock could realistically fail. Corrosion wouldn't affect just the redundant sea cock though, so if I had to replace any sea cocks due to corrosion then i'd obviously have to deal with the redundant one then, as the risk of failure would be there.
 
Nick, in years to come a redundant sea cock is a liability as one day it will corrode to nothing, I dread old boats with old skin fittings, especially when im around engine rooms where a slip of the foot could break it off , believe me ive seen the result of a rotten seacock(no names mentioned) not a pretty sight, get it glassed in.

Another point, are there any ferrous parts of the valve that could upset the gyro like the handle, just thinking magnetically.
 
Dis-used Seacock

If I spotted a dis-used seacock tucked away and forgotten about for convenience I would immediately ask what other neglectful tricks had been played on that boat.

Seacocks should all be exercised several times each season, and if any are not required I would permanently remove them.

The boat I bought last year had sat on the mooring for 3 years, and after survey the aft heads inlet valve seized shut (gate valve). When I removed it a few weeks ago the thing disintegrated due to de-zincification. Had this happened when I was trying to get it to open the speed the water would have entered through a 1.5" hole would have been frightening.

A Glass fibre repair underwater does not have to be that pretty, but is relatively simple to do.
 
if it were mine i would close it and cap it, with a view to the next time the boat being pulled out having it removed and glassed over. I certinaly wouldnt consider leaving it long term. As has been pointed out these things can degrade and if it has been capped you may find it overlooked.
just my thoughts
 
Nick_H said:
The background to the question is that the gyro has been installed directly above the sea cock for the fire hose, making it extremely difficult to reach to turn it on/off. I'm obviously not happy to have a sea cock I can't get to in an emergency, so my plan is to have a new one fitted in a more accessible position, but that leaves the problem of what to do with the old one. To blank it off will be near impossible due to the restricted access, so the only option I can think of is to turn it off and leave it, other than craning out the gyro again to get access.

As you say, the concern is galvanic corrosion. I can't see any other way a redundant, permanently closed sea cock could realistically fail. Corrosion wouldn't affect just the redundant sea cock though, so if I had to replace any sea cocks due to corrosion then i'd obviously have to deal with the redundant one then, as the risk of failure would be there.
Click to expand...

Is it possible to grind the outside of the skin fitting off from the outside of the boat, thus releasing the remainder of the seacock inside the boat, and then just fish it out from under the gyro? Could the resulting hole not then be ground back and reinstates solely from the outside - or does the reglassing have to happen from both sides? (Genuine question, I don't know how this works at all)

Cheers
Jimmy
 
jimmy_the_builder said:
Is it possible to grind the outside of the skin fitting off from the outside of the boat, thus releasing the remainder of the seacock inside the boat, and then just fish it out from under the gyro? Could the resulting hole not then be ground back and reinstates solely from the outside - or does the reglassing have to happen from both sides? (Genuine question, I don't know how this works at all)

Cheers
Jimmy
Click to expand...

I've been thinking the exact same Jimmy, and have e-mailed the shipyard to see if they can do it when it goes in for antifouling just before Easter. At a stretch I think someone could get some resin soaked matting roughly in position on the inside of the hole, if the GRP work can't all be done from outside.
 
Nick_H said:
I've been thinking the exact same Jimmy, and have e-mailed the shipyard to see if they can do it when it goes in for antifouling just before Easter. At a stretch I think someone could get some resin soaked matting roughly in position on the inside of the hole, if the GRP work can't all be done from outside.
Click to expand...

Nick,

I'd definitely want to make sure that a larger piece of matting was rolled on the inside (after paint was scraped/sanded off and area roughened for better keyin). Yes should be able to do it all from outside, but I'd not be happy!

cheers

V.
 
An alternative to glassing the hole shut if access is difficult; if it's a bolted flange have a piece of polycarbonate cut to the shape of the flange and bolted in its place, if its a threaded through-hull fitting buy or have turned up a blanking plug to take the same clamp bolt. I have seen ready-made blanking plugs but I don't know how widely available they are.
 
Nick_H said:
I've been thinking the exact same Jimmy, and have e-mailed the shipyard to see if they can do it when it goes in for antifouling just before Easter. At a stretch I think someone could get some resin soaked matting roughly in position on the inside of the hole, if the GRP work can't all be done from outside.
Click to expand...


Hmm but after grinding off the flange it will still be very well stuck with sealant on the inside and will require quite a blow to remove it on the inside

I'd prefer to leave the seacock installed in the boat, redundant, than have it GRP plugged without access to the inside for GRP work. I wouldn't want a one-sided patch below the waterline. There's no reason it will corrode at different rate to other seacocks in the boat. But I would get shipyard to clean it properly from underside back to the metal, and fill up inside the seacock from the outside of the hull with 3M 5200 polyurethane, in a big plug, wiped flush with the hull. Then paint an epoxy patch over it. Then antifoul it. This will stop seawater reaching the ball ie where 2 metals are together, so (a) eliminating glvanic corrosion and (b) stopping it getting wet ergo it cannot become an anode by virtue of being wired to the boat's bonding system (if it is so wired). By doing this you do not end up with a solution that has dubious mechanical strenght (ie the one-sided patch)
 
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jfm said:
By doing this you do not end up with a solution that has dubious mechanical strenght (ie the one-sided patch)
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Im pleased you mention the one sided patch. I am also seriously concerned about a one sided patch.

I converted one of my first boats from inboard to outboard and plugging the 2 inch shaft hole was very difficult.

I had experience of building with fibreglass ( canoes) and repairing canoes which had broken in half.

Plugging the 2 inch hole was far more difficult.

Cured fibreglass isnt easy to bond to.

rounded off thick stainless blanking plate inside and out with rubber washer inside and out , bolt through the centre, job done !

not read the full thread , sorry if it has already been said.

http://www.vetus-shop.com/electrica...pe-ebv-12-volt-12and34-incl-panel-p-1357.html



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