Replacing or servicing seacocks in the water

[cha0s]

I'm quite sure this has been asked before, but a quick search hasn't turned up a result. I have a lot of seized open seacocks with old brittle hoses connected to them. I need to service (and possibly replace) the seacocks, but cant get the boat out of the water.
I found a product online called seabung which is designed to allow you to remove seacocks in the water, but this won't work for me, as a lot of the through hulls are oval with a strainer thing on them. BUT THIS GOT ME THINKING.

SO I'm wondering if theres a way to cut a bit of rubber (from a large tyre inner tube or something) or maybe even a bit of really thick plastic and then apply 3m 5200 or some other goop around the edges, and cover the through hull fitting from the outside (over the top of the irregular shaped through hull fitting), then safely work on the seacock without fear of the boat sinking if I break something when I start trying to free up the seacock.

I'm sure I read something about a large rubber cup type thing (like a plumbing plunger) that would cup over the outside of the hull but I can't find anything on line to match this description - and in any case, theres a few through hull penetrations in positions where I don't think something like this would seal.

I need a way to make it work with a sheet of plastic or rubber.

[Ziggy]

Depends how dangerously you like to live. By the way, 5200 might work, but it would then be really nasty to take off.

If I were in your place, I'd haul the boat. There's probably other stuff you can do below the waterline, like new antifouling or at least scrub the bottom.

[cha0s]

The boat is in the pacific, the closest place that has a big enough slipway to haul her out is 800 NM away. Before we go to sea, the raw water intake's need to be made safe. Almost every other through hull could be bunged shut, but obviously we need raw water for cooling the engine.

I feel its living dangerously going to sea for a week with so many seized open seacocks - with bungs shoved in them.

Is there another non setting type of sealant that would hold a rubber patch in place for a day or so, and be easier to clean off.

[kellymj]

Don't know if this will help, I used a diver. We have strainers on the outside of the hull. We used a combination of a dry cleaning bag with a plastic grocery bag behind it, slapped up against the strainer. On the inside I swapped out the seacock. This method gave me a very slight trickle of water initially which then stopped before I bedded and tightened the new seacock. From the time the driver went down to completion was probably under 10 minutes. It was a marelon seacock.

Marty
S/V True Colors


Sent from my iPad using Cruisers Sailing Forum

[Rustic Charm]

Cutting a balloon up and putting it over the strainer will also slow up the ingress significantly enough to change it. I'm presuming your seacock's are threaded though and not bolted to the hull?

If there bolted I wouldn't take the chance.

Another option is to tie to a jetty somewhere and wait for the tied to go out and do as many as you can that way. That is usually free.

[Cheechako]

So.... are these tapered bronze seacocks? (TB) Your plan is to remove the seacock? If TB... then just plug from the outside and remove the taper part, clean it and the inside of the seacock and apply liberal amount of grease or lanolin. If gate valves or ball valves... that will require replacement.
If TB... just loosening them and rotating them shut might work to get you the one week....
What type are they??????

[Rustic Charm]

Originally Posted by cha0s

I feel its living dangerously going to sea for a week with so many seized open seacocks - with bungs shoved in them off.

Hell yes!

Are you just wanting to 'replace' the seacocks or are you looking at something to go to sea with?

I know they have to seaward strainers, but What sort of seacocks are they exactly?

[Ziggy]

Originally Posted by cha0s

The boat is in the pacific, the closest place that has a big enough slipway to haul her out is 800 NM away. Before we go to sea, the raw water intake's need to be made safe. Almost every other through hull could be bunged shut, but obviously we need raw water for cooling the engine.

I feel its living dangerously going to sea for a week with so many seized open seacocks - with bungs shoved in them.

Is there another non setting type of sealant that would hold a rubber patch in place for a day or so, and be easier to clean off.

If you can bung the thruhulls from the outside, then you can service or replace the seacocks. I think that would be safer than rubber patches. If the boat was sitting in one place neglected for some time, the bottom is likely badly fouled and it may be difficult to get a good seal with a patch.

If you're lucky, you may be able to unscrew the seacocks without breaking the seals between the thruhulls and the hull.

Unless the strainer is part of the thruhull, you may be able to remove it. It's usually held in place with 4 screws.

[bsurvey]

no caulking will dry underwater except splash zone
you can use plastic sheet and a hard wood plug on the outside as water pressure o the hull displacement will hold it in.


plumbers plugs will work also suction cups at harbor freight will also work cups have a cam like the kind that glass guys use. hull has to be smoothy around the through hull to get a seal.

[HopCar]

"no caulking will dry underwater except splash zone"
5200 will set underwater.

[Pirate999]

I've done this before. We used a large toilet plunger over the thru hull. The pressure/suction kept it firmly in place when the thru hull/seasick was open. Proceeded to replace the seacock with zero dribble or leak. Always had someone in the water just in case. When it was done we closed the new seacock and the plunger dropped off. It does take two people.

[Terra Nova]

Originally Posted by Ziggy

...If you're lucky, you may be able to unscrew the seacocks without breaking the seals between the thruhulls and the hull...

Come on you guys! Use your heads!

If the thru-hull fitting is temporarily plugged, so water doesn't fill the boat, how can you get a wrench on it to prevent the thru-hull from turning when you try to unscrew the seacock?

[kellyp08]

Interesting problem. In the Islands they used to replace bottom planks on old schooners by careening - with halyards secured to block and tackle on a dock or another schooner.

If no dock is available and you had access to 3 anchors you could careen the vessel with main halyard to an anchor rode set on the side opposite the seacock in question and two other anchors set away fore and aft on the side of the seacock you want to work on. Then take up on the halyard until the toe rail is awash and careen the vessel to expose the seacock that you want to work on/replace (providing that the seacock is not too far down - like at the hull/keel junction).

[Cheechako]

Originally Posted by Pirate999

I've done this before. We used a large toilet plunger over the thru hull. The pressure/suction kept it firmly in place when the thru hull/seasick was open. Proceeded to replace the seacock with zero dribble or leak. Always had someone in the water just in case. When it was done we closed the new seacock and the plunger dropped off. It does take two people.

any suction device will not work in this instance... the seacocks are open! no suction will occur! Even if they weren't open... as soon as he removes the valve there will be no suction!
something thin enough for the water pressure to hold it might work. but it's pretty dicey.

[Ziggy]

Originally Posted by Terra Nova

Come on you guys! Use your heads!

If the thru-hull fitting is temporarily plugged, so water doesn't fill the boat, how can you get a wrench on it to prevent the thru-hull from turning when you try to unscrew the seacock?

I found that in most cases the sealant on the thruhull (polysulfide) is set so firmly that it's very difficult to turn even if you try. But you can't count on it.