Sea-cock change - whilst afloat...

[lpdsn]

One would think if the OP is going to take on a job which involve chancing it while in the water , he the type of guy who could tell by looking and tapping the fitting before removing it , and if it was that bad he haul out ASAP .

He could risk it. He could very well get away with it, but de-zincification isn't as easy to spot as all that unless it is right the way through so it could really go wrong. I really see no point in advocating a high-risk strategy when a low-risk one will achieve the same ends.

Not long after I bought my boat I seriously considered doing a sea cock in the water as the local yard wanted €1,500 for a lift out and splash (they're probably still reminiscing about the days of the Celtic Tiger). In the end I lifted 6 months later somewhere far cheaper and as well as doing the anti-foul I attempted to replace four seacocks. Two went well. In a third case the elbow bend broke and in the fourth it clearly needed replacing. No issue, I just replaced the whole gubbins for those two. If I had attempted it in the water I'd have had two holes below the waterline. It would not have been wise to go to sea with them bunged (yard I eventually lifted at was >50miles away) and I've had been forced to pay the €1,500 or whatever extra they wanted to bung on top for an emergency lift.

It just wasn't worth it. The OP has a very minor problem. If he takes a careful approach he can change the seacock at his leisure when out for anti-fouling. If it goes wrong he can get an angle grinder and remove the skin fitting in <30 mins. Why take the risk of turning a minor issue into a crisis?

 

[maby]

A few years ago, when we were looking for an upgrade to our boat, we looked round a very nice Hunter (the US kind) forty-odd footer that was being offered at a very attractive price by the local boat yard. It was just a few years old and looked almost new. I was exploring the panels and slipped a finger behind one of the wall panels - I found dry mud. Then the yard came clean - they had bought it off an insurance company and fully refitted it - the previous owner had taken it into his head to do some sea-cock maintenance with it in the water and it had then spent a couple of weeks sitting on the bottom while the insurers had found someone with a big enough floating crane to lift it back up!

Personally, I would recommennd against it - if you do decide to go ahead, plan for the worst - have plenty of help at hand, plugs, pumps, buckets for bailing and make sure that you know where the crane driver is in case you need a very urgent lift out!

 

[sailaboutvic]

He could risk it. He could very well get away with it, but de-zincification isn't as easy to spot as all that unless it is right the way through so it could really go wrong. I really see no point in advocating a high-risk strategy when a low-risk one will achieve the same ends.

Not long after I bought my boat I seriously considered doing a sea cock in the water as the local yard wanted €1,500 for a lift out and splash (they're probably still reminiscing about the days of the Celtic Tiger). In the end I lifted 6 months later somewhere far cheaper and as well as doing the anti-foul I attempted to replace four seacocks. Two went well. In a third case the elbow bend broke and in the fourth it clearly needed replacing. No issue, I just replaced the whole gubbins for those two. If I had attempted it in the water I'd have had two holes below the waterline. It would not have been wise to go to sea with them bunged (yard I eventually lifted at was >50miles away) and I've had been forced to pay the €1,500 or whatever extra they wanted to bung on top for an emergency lift.

It just wasn't worth it. The OP has a very minor problem. If he takes a careful approach he can change the seacock at his leisure when out for anti-fouling. If it goes wrong he can get an angle grinder and remove the skin fitting in <30 mins. Why take the risk of turning a minor issue into a crisis?

I take your point , and I sure there thousands that wouldn't untake this job in or out of the water , but there also many other that would and as long as you take precautions there isn't any reason why it can't be done , yes there a risk but there also a risk every day you get out of bed and if the worst came to the worst unless he panic he going to get a bucket or water in the boat probably like some find each weekend when they visit there boat from the shaft .
The job is going to be done in his Marina which I expect will have haulout facilities, so there be no need for him to go out to sea with bung in his hull .
BUT let's get back to what the OP ask ,
Basically he said he plain to do the job and his question was

" 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."

Your suggestion and other are not to do it , that's fine , I sure he took note of that .
My suggestion as well as advising him what loctite I use and why , I also given him some suggestion on a way he can do it .
I take your point , you don't agree , but what your capable off and what I am capable off or come to that what the OP is capable off , very different things .
At the end of the day it's up to the OP , no point arguing the point with me ,
it's not me doing the job , if it was I would be asking advise if I should do it , I know very well what a lot will say .


No long ago someone asked the question about changing the rigging while the mast was still up ,
many suggested he need to remove the mast to be in the safe side , this can happen , that can happen , plus he can do a better job ,
but as I know because I did mine last Sept and many many other know you can safely replace rigging with the mast up as long as you do it the right way .
It all comes down to the person and what is capable off .

The suggestion paul rainbow made in #38 is a great one and the OP should try that first before anything else .

 

[icarusbop]

Hello all:
This is the original poster, I'm back to provide an update on what happened so hopefully this post might be useful for someone else in the future. I know it’s been ages since I updated, but I’ve been busy and waiting for the right weather opportunity.
First of all thanks for everyone’s contribution, it has all been very helpful. I also spoke to lots of people in the marina and advice seemed to be split between don’t touch it to it'll be dead easy.
A few things I took away from all the discussions were.
If you are going to try this, have a backup plan, and a backup backup plan. Make sure everything you need for every eventuality is close to hand with you, including your mobile to call for help if things go wrong.
I decided to go ahead and try the change whilst afloat, this was for a couple of reasons. Firstly, I knew the sea-cock was faulty and if there was another failure pipe/ fitting, I had no way of shutting off the water, especially if I was not there at the time of the failure, and it's possible my knowledge of the faulty sea-cock and not changing it might give the insurance company a get-out if there was such a catastrophe.
After I decided it needed doing now rather than at my next lift, the second reason to try it afloat was, the marina has a lift on-site, and I could either lift and change the cock (with the potential of a leak upon re-launch), or try the change afloat and lift if there was an issue. One of these options was cheaper than the other by at least £700, so I picked a day that staff were around to do an emergency lift should I need it.
My backup plans included bungs, tarpaulin patches, underwater gorilla tape, rags and friends, to slow / stop the leak whilst the emergency lift was arranged, if one was needed.
The procedure went well, I bunged the outside skin fitting, and because the pipe was calcified up and there was no flex in it I chopped it above the waterline with an oscillating saw. I used a large syringe and thin flexi pipe down the inside of the pipe to drain out any water still in there.
When I had removed all the water I could I used a chain wrench and a big pipe wrench to remove the seacock, as there was an elbow between the skin fitting and sea-cock, I could minimise the amount of sideways and rotational stress on the skin fitting itself.
The sea-cock came off quite easily, at this point water started coming in from the skin fitting – apparently the outside bung as not as tight as it might have been, but a friend to hand stemmed the flow with rags and muscles, allowing me a minute or so the clean the old gunk off the thread. I applied the 3m thread sealing cord and screwed on the new sea-cock (here there was a slight delay, I needed to screw the cock on in the closed position to stop the water flow, but it could not screw on closed due to the handle position, I spent about another minute removing the handle from the new sea-cock whilst my friend held the water out), once the new sea-cock was only a few threads on the water flow stopped, and we could relax a little. I then took my time screwing the new unit on properly and positioning it so the handle could operate.
We took on about ½ bucket of seawater during the procedure which was easily bailed out and dried.
I found that the horsetail on the old fitting had sheared off during me removing the old unit, it was completely de-zincified, so it’s probably a good job I changed it when I did as it was probably close to failing anyway. (I’ve since got a new hose tail DZR and fitted it and now connected the holding tank back on with new pipe.) The skin fitting itself is sound and looks to be DZR, unlike the sea-cock. The old sea-cock was ¾ open and seized up good and proper – it was never going to work again.
The 3M sealing cord is great, it does not leak and allows the unit to be not fully screwed until you get to the bottom of the thread, so you can position the sea-cock in the beat place for operation.
All in All, it went well with only a bit of stress, and I’m more comfortable knowing it has been changed.
Again, thanks to all for the input and help.

 

[fisherman]

Well done. I had this idea for such work. Get a short length of bike inner tube, with valve. Fold and tie Both ends, push the non valve end down the skin fitting, inflate it. If the inside was constricted with a bit of plastic tube it would be easy to feed a new sea cock over it. Not had the chance to try it, will it work?

 

[Plum]

Well done. I had this idea for such work. Get a short length of bike inner tube, with valve. Fold and tie Both ends, push the non valve end down the skin fitting, inflate it. If the inside was constricted with a bit of plastic tube it would be easy to feed a new sea cock over it. Not had the chance to try it, will it work?

Well done indeed to the OP and your idea certainly looks doable although trying to stuff the deflated innertube through the skin fitting with water flow forcing it back may be a bit of a challenge untill you have inflated it. Now you have published your idea you now have to try it out and report back to us all!!

Www.solocoastalsailing.co.uk

 

[fisherman]

Well done indeed to the OP and your idea certainly looks doable although trying to stuff the deflated innertube through the skin fitting with water flow forcing it back may be a bit of a challenge untill you have inflated it. Now you have published your idea you now have to try it out and report back to us all!!

Www.solocoastalsailing.co.uk

I was thinking it could have a dowel down the middle, but as you say, maybe a lot of flow to overcome and slow to operate