Sea-cock change - whilst afloat...

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icarusbop

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My toilet outlet 1 1/2" sea cock has failed in the open position, it's not leaking - I just can't close it...
I'm considering changing it out, with the boat still in the water! The plan so far is to heel the boat so the outlet is above the waterline, put in a bung for good measure and change the cock out with the boat in this position.

I am only changing the sea-cock, not the hull fitting and there is an elbow fitted between the skin fitting and the sea-cock - so due to the angle of the sea-cock there is very little (if any) chance of the skin fitting rotating when I undo the sea-cock. I'm confident the skin fitting will stay secure.

For obvious reasons, I want to be as prepared for any "unforeseen eventualities" as possible.

I'm unsure if I should use PTFE tape or loctite 55 thread tape for the thread seal. There is a lot of support for both options, but I've never tried the loctite 55 cord before.

Any other ideas or suggestions much appreciated.

Regards:

IcarusBop
 
icarusbop said:
I am only changing the sea-cock, not the hull fitting and there is an elbow fitted between the skin fitting and the sea-cock - so due to the angle of the sea-cock there is very little (if any) chance of the skin fitting rotating when I undo the sea-cock. I'm confident the skin fitting will stay secure.
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How do you know that the skin fitting and elbow bend are perfectly OK?

Changing a seacock is one of these jobs that often seems to start off small and grow as you do it.

Chances are though that you've probably just got a build up of calcium inside the ball valve.

I usually just use PTFE tape on teh threads. However this year I did end up using Sikaflex on the thread of one hose connector as recommended regularly by a few forumites and it worked well.
 
I done this a few times now , as long as your hull fitting doesn't move it fine and by the sound of thing you have an elbow between the hull fitting and the sea cock ,so all should be ok lot less change the hull fitting going to move .just have a good look around the hull fitting to make sure it won't snap off .
Bung is a good idea if you can get one in but other wise , makesure you have the right thread sea cock i have always use loctite thread 55 , worth its weight in gold , never have had a problem with it and it also mean you can set the sea cock in the direct you want it as it will aloud you to turn the sea cock back a bit .
What I have done a few times is undo the old sea cockand screw the new one in , you will get some water in , but not as much as you think , as I said if you can bung it before hand all the better.
If you happen to be one of these people who removing the speed transducer scare you , best wait till you can get it out of the water .

One last thing , before changing the sea cock , take the handle off the old sea cock and use grips and slowly try and move it back and fro , you might be able to free the old sea cock .
 
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I would be sure to either have an open Chandlery nearby or spares for 'anything that could go wrong' on board, such as a new through hull. Plus all the tools for doing the complete (through hull) job.

I contemplated drying out between tides to repack a slightly leaking through hull and very glad I didn't as I eventually had to destroy the thing to remove it. :eek:
 
lpdsn said:
How do you know that the skin fitting and elbow bend are perfectly OK?
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I don't know for sure, the boat is 14 years old and was surveyed in March this year (out of the water), I'm assuming the survey would have picked up any concerns about the hull fitting and the age helps too.

lpdsn said:
Chances are though that you've probably just got a build up of calcium inside the ball valve.
Click to expand...

I assume the same, but I've had a pair of grips on the handle and have pushed has hard am I'm willing and still no movement, I suspect the previous owner has never closed it in the 14 years since the boat was built.
 
Thanks for the replies so far, it's nice to know other people have done this.

an extra question I thought of - do I need to fit a fibre washer between the fittings, if so, I'll need to make sure I have one with me.
 
sailaboutvic said:
One last thing , before changing the sea cock , take the handle off the old sea cock and use grips and slowly try and move it back and fro , you might be able to free the old sea cock .
Click to expand...

I've had a pair of grips on the handle and have pushed has hard am I'm willing and still no movement, I suspect the previous owner has never closed it in the 14 years since the boat was built.
 
icarusbop said:
Thanks for the replies so far, it's nice to know other people have done this.

an extra question I thought of - do I need to fit a fibre washer between the fittings, if so, I'll need to make sure I have one with me.
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Between what fitting ? The elbow is an female or Male in which case you fit the appropriate connector between the elbow and sea cock , the other end of the sea cock you have a nozzle which will fit into your pipe . Don't forget to put two J clips on the pipe . Also when removing the seacock of the elbow , get someone to hold the elbow to stop it moving on the hull fitting so not to disturb the seal .
 
icarusbop said:
I've had a pair of grips on the handle and have pushed has hard am I'm willing and still no movement, I suspect the previous owner has never closed it in the 14 years since the boat was built.
Click to expand...

Remove the handle and put grips on the shaft and try moving it the opposite way , you may just be lucky it only need to move a little bit to get it started , it worth a try . Maybe a hot air gun , be careful you working next to fibglass
 
icarusbop said:
I don't know for sure, the boat is 14 years old and was surveyed in March this year (out of the water), I'm assuming the survey would have picked up any concerns about the hull fitting and the age helps too.



I assume the same, but I've had a pair of grips on the handle and have pushed has hard am I'm willing and still no movement, I suspect the previous owner has never closed it in the 14 years since the boat was built.
Click to expand...

Rather remiss of your surveyor not to have checked it functioned.

As I said, it is probably just a build up of Calcium deposits, but at 14 years old you have no way of knowing that de-zincification hasn't occurred. The RCD just specifies 5 years, which is a loophole that some production boatbuilders use just to fit brass.

If it were me, if I couldn't free it, which it seems you can't, I'd ensure the hose was securely double clamped then just live with it until the next lift out for anti-fouling. It's lasted 14 years untouched but you don't know what the impact of getting the ball valve off will be if it is in poor condition.
 
lpdsn said:
If it were me, if I couldn't free it, which it seems you can't, I'd ensure the hose was securely double clamped then just live with it until the next lift out for anti-fouling. It's lasted 14 years untouched but you don't know what the impact of getting the ball valve off will be if it is in poor condition.
Click to expand...

I'd also leave it until the next lift out.
 
The chances of it having seized to the through hull, or even been bonded to it with some kind of loctite, seem too high to me.
It would be quite possible to disturb the through-hull while 'persuading' the seacock to come off it.
I'd leave it.
Check the clip.
Get a tapered bung to fit the hose or hole in the hull and leave it taped to the through hull just in case.

Or dty out on a tide and do it properly, even that can be fraught.
 
Just thinking aloud here- if it's probably calcium build up, how about putting the bung in from the outside. Removing or perhaps not even removing the pipe from the seacock and pouring Rydlyme down the fitting to dissolve the calcium? No idea of the practicalities but it might be less risk? Feel free to tell me it'll eat away the chrome/seacock etc.
 
ballyabroad said:
Just thinking aloud here- if it's probably calcium build up, how about putting the bung in from the outside. Removing or perhaps not even removing the pipe from the seacock and pouring Rydlyme down the fitting to dissolve the calcium? No idea of the practicalities but it might be less risk? Feel free to tell me it'll eat away the chrome/seacock etc.
Click to expand...

Thats what I was thinking. Well worth a bash.
 
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