I spent the day on my new boat yesterday inspecting everything from bow to stern and making a full inventory of everything that was included in the sale. One of the tasks was to identify all through-hull penetrations and to exercise all seacocks.

Everything was in working order, except for the 2 x head seacocks. (raw water inlet and waste discharge) Both of these are frozen in the closed position. Am guessing they haven't been used for some time.

There were only two other seacocks; raw water engine intake and galley sink waste discharge, which both worked fine.

So question, how do I fix a frozen seacock. I am thinking the following, but would like feedback or suggestions;

1. Undo 2 x stainless hose clamps from hose on seacock
2. Remove hose from seacock
3. Spray liberal amounts of something (WD40?) all over and inside the seacock.
4. Wait an unspecified amount of time
5. Try to exercise the seacock.
6. Repeat steps 3 - 5 as required until I have a working seacock.

7. If all else fails, replace the skin fitting and seacock at haul-out, but I would like to get the head working before the boat is due for anti-fouling.

Any tips?

What should I spray on the seacock?

Anything better than WD40?

Here is a pic if it helps. The seacocks in question are the ones on the left and right. The one in the middle at the back is the engine raw water intake.

I had a similar issue with the same type of sea cock. Take the hose of and have a look, in my case I found a calcification build up, it was nervous work gently chipping it away, the ball and seal where in good nick and is still in service today. Good to see the bungs are good to go

Your lucky both handles are SS. I found the same when I bought my boat. The balls will be in a plastic liner. I just worked the handles back and forth till they freed up. There will be just a bit of shell build up on the seawater side of the inlets.

Thanks Woko and Ramona. I was hesitant to add too much force yesterday, but have a better idea now. Thanks for the replies.

And yes there are wooden bungs for all through hull openings.

Pretty simple to dive in and ram a couple of bungs in. Then undo the existing ones and replace. Just be sure to use a wrench on the thread to hold against the force on the unwinding valve.

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Enigma1 said..
Thanks Woko and Ramona. I was hesitant to add too much force yesterday, but have a better idea now. Thanks for the replies.

Just use one hand to brace against the pressure on the handle. Just move it a few millimeters till the inside hole of the ball slices up the shell.

If you're not satisfied with the wd40, try CorrosionX. Well worth the cost, does a much better job IMO.

Looks like there is enough thread under the valve to get a new one on. Clean up the thread under the valve really well. Dive and bung the through hull. Cut under the valve using the bottom of the valve as a guide to get a straight cut. Battery angle grinders are good. Have new valve ready to go. Make sure its the right size and thread!! Screw new valve on.
This was a plan we came up with but lifted the boat instead.
This is if you cant free it up with small up and down movements, Wd etc.
Wooden bungs should be dry and hard they expand when they get wet. Old soft ones aren't great.
Move your valves regularly!

Thanks for all of the replies. Got a plan of attack now, escalating from jiggling the handle to remove any shell buildup, to WD40, to CorrosionX to full on replacement (in the water or out of the water).

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tarquin1 said..
[SNIP]
Wooden bungs should be dry and hard they expand when they get wet. Old soft ones aren't great.
Move your valves regularly!

Yes there was rainwater in the bottom of the cockpit locker. I have now bailed it out and sponged up every last drop. Will take the bungs and put them in the sun next time I am on the boat and if they don't dry up or are damaged, will replace them.

Got the two frozen seacocks sorted today. The raw water intake was easier than the waste discharge, but in the end didn't even need to remove the hoses. Thanks for the tips.

BTW I also let the wooden bungs dry out in the sun today.

That's sounds easy. When you put the new head in and of course replacing the hoses pay attention to the in side of the outlet valve, it could be restricted and that will bit you when you least expect it

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woko said..
That's sounds easy. When you put the new head in and of course replacing the hoses pay attention to the in side of the outlet valve, it could be restricted and that will bit you when you least expect it

Yeah thanks woko. Will definitely have a good look when I install the holding tank. Am assuming the waste discharge side may have some buildup.