Seacock Quality... Replace?—Currently on the hard.

Jun 14, 2025
42
Hunter 1981 30 Chesapeake
So one of these is stuck and the other turns over 90 degrees.

Should I replace these seacocks?

I asked to just replace all the seacocks... Reason I ask is because the boatyard contractor told me that might be a bit much and these bronze fittings usually last forever. He said we could just do the valve levers.

Just wanted a second or third opinion.

Thank you!
 

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jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,070
CAL 35 Cruiser #21 moored EVERETT WA
Hey, it is your boat. Your choice.

I would replace all the through-hulls on a boat I just bought. I did that on my boat.
You have no idea how they have been maintained. Your boat was new in 1981. That is 44 years ago. :yikes:

Seacocks and through-hulls do not last forever. They are replaced like wiper blades on a car. They are more critical to protecting your boat from sinking.
 
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Jun 14, 2025
42
Hunter 1981 30 Chesapeake
I don't know the age of the thru hulls. The brass looks decent with my eyes. Is it a hard job to do? Hmm... I'm Stewing on it. Leaning towards just living on the hard and replacing them when possible.
 
May 17, 2004
5,642
Beneteau Oceanis 37 Havre de Grace
The second attachment looks like the notches on the handle are intact, so I presume that’s the one that’s stuck? It shouldn’t be able to turn more than 90 degrees with those notches. If that’s the case than the first attachment must be the one that turns too far?

If it’s stuck and you don’t know how old it is I would replace it. Being stuck is more than just a handle problem. The first one looks gnarly enough that again without knowing its pedigree I’d replace that too.

To be pedantic - what you have are technically not “proper” seacocks, they’re thru hull fittings attached to ball valves. There are major manufacturers that build them that way, so I won’t go so far as to say it’s absolutely wrong, but a traditional seacock is generally preferred if you’re replacing them anyway.
 
Jun 14, 2025
42
Hunter 1981 30 Chesapeake
The second attachment looks like the notches on the handle are intact, so I presume that’s the one that’s stuck? It shouldn’t be able to turn more than 90 degrees with those notches. If that’s the case than the first attachment must be the one that turns too far?

If it’s stuck and you don’t know how old it is I would replace it. Being stuck is more than just a handle problem. The first one looks gnarly enough that again without knowing its pedigree I’d replace that too.

To be pedantic - what you have are technically not “proper” seacocks, they’re thru hull fittings attached to ball valves. There are major manufacturers that build them that way, so I won’t go so far as to say it’s absolutely wrong, but a traditional seacock is generally preferred if you’re replacing them anyway.
This was exactly my line of thinking and knowledge. I was challenged a bit by the contractor as he thinks the thru hulls look good and he doesn't want me to 'waste my money' on replacing perfectly good thru-hulls as it's an expensive job. What do you think? I didn't think the job was too intensive but I've not personally done it before.
 
Jun 11, 2004
1,757
Oday 31 Redondo Beach
Going against the general rule of always leaning toward the side of caution I would think if you could get the handles replaced, the stems cleaned up and the valves freed to easily move through their proper 90 degree arc (and no more) you would probably be okay.

But if it is something you are going to lose any sleep over you should just go ahead and replace them.
 

dLj

.
Mar 23, 2017
4,377
Belliure 41 Back in the Chesapeake
Well, I'm one for making sure my boat doesn't sink and tend to stand on the side of the fence of replace the whole thing.

However, looking at your pictures, it looks like you can just change out those ball valves and be fine. I would definitely be thinking to change to bonafide seacocks as @Davidasailor26 said above - and after pulling off those valves definitely inspect those thru hulls. But there is nothing in those photos that looks alarming enough at this point to do that whole job right now.

But be prepared to do so, however, after pulling those valves in case those thru hulls are worse on the inside than they look on the outside...

dj
 
Jun 11, 2004
1,757
Oday 31 Redondo Beach
Well, I'm one for making sure my boat doesn't sink and tend to stand on the side of the fence of replace the whole thing.

However, looking at your pictures, it looks like you can just change out those ball valves and be fine. I would definitely be thinking to change to bonafide seacocks as @Davidasailor26 said above - and after pulling off those valves definitely inspect those thru hulls. But there is nothing in those photos that looks alarming enough at this point to do that whole job right now.

But be prepared to do so, however, after pulling those valves in case those thru hulls are worse on the inside than they look on the outside...

dj
I can't disagree with anything said here.

If you are going to just replace the old valves try to make sure you don't twist the through hulls in their bedding . If you do you might as well replace then too.
 
Jun 14, 2025
42
Hunter 1981 30 Chesapeake
I will be living on the boat a significant amount throughout the year. I was a little surprised that they weren't flanged, but if I'm getting positive vibes on these thru hulls on a boater forum, they might just be okay to stick with until my haul out in 2 years. Still thinking on it. Will investigate soon.

Appreciate the perspectives and was wondering what you think about this article from How To Marine on proper seacocks: Replacing Thru-Hulls and Seacocks - Marine How To

Mine certainly do NOT meet their standards, which bothers me a bit.
 
Jun 14, 2010
2,326
Robertson & Caine 2017 Leopard 40 CT
I can't disagree with anything said here.

If you are going to just replace the old valves try to make sure you don't twist the through hulls in their bedding . If you do you might as well replace then too.
There’s no way he’s going to be able to get those off without breaking the seal of the thru-hull bedding. I’d replace the whole assembly of both. Those original fittings (or new Groco equivalents) are not that expensive, and when you consider the time and effort to try to restore them it’s not worth it. He can use bronze like he has or Forespar Marelon and it’ll be an improvement.
He just needs to remove them, wipe with solvent, scrape and sand it level, solvent wipe again, and install the fittings. (He should have a helper on the other side of the hull when installing the thru-hulls). If he’s ready with the right tools and materials it should take about 2 hours for each one, 4 if you double it or a whole day when you figure in the novice factor.
Tips for @testingthewaters91 - use 3m 4200 sealant (NOT 5200 - that’s only for things you will never need to remove) and if the old sealant doesn’t want to let go heat the metal fitting with a torch.
 

dLj

.
Mar 23, 2017
4,377
Belliure 41 Back in the Chesapeake
I will be living on the boat a significant amount throughout the year. I was a little surprised that they weren't flanged, but if I'm getting positive vibes on these thru hulls on a boater forum, they might just be okay to stick with until my haul out in 2 years. Still thinking on it. Will investigate soon.

Appreciate the perspectives and was wondering what you think about this article from How To Marine on proper seacocks: Replacing Thru-Hulls and Seacocks - Marine How To

Mine certainly do NOT meet their standards, which bothers me a bit.
That's a great article!

dj
 
Jun 14, 2010
2,326
Robertson & Caine 2017 Leopard 40 CT
I will be living on the boat a significant amount throughout the year. I was a little surprised that they weren't flanged, but if I'm getting positive vibes on these thru hulls on a boater forum, they might just be okay to stick with until my haul out in 2 years. Still thinking on it. Will investigate soon.

Appreciate the perspectives and was wondering what you think about this article from How To Marine on proper seacocks: Replacing Thru-Hulls and Seacocks - Marine How To

Mine certainly do NOT meet their standards, which bothers me a bit.
Great article - that’s the ideal way to do it. However, if you’re just daysailing and vacation cruising in the Chesapeake you can use bronze or Marelon ball valves (or Marelon seacocks) instead of bronze sea cocks.
 
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Jun 14, 2025
42
Hunter 1981 30 Chesapeake
There’s no way he’s going to be able to get those off without breaking the seal of the thru-hull bedding. I’d replace the whole assembly of both. Those original fittings (or new Groco equivalents) are not that expensive, and when you consider the time and effort to try to restore them it’s not worth it. He can use bronze like he has or Forespar Marelon and it’ll be an improvement.
He just needs to remove them, wipe with solvent, scrape and sand it level, solvent wipe again, and install the fittings. (He should have a helper on the other side of the hull when installing the thru-hulls). If he’s ready with the right tools and materials it should take about 2 hours for each one, 4 if you double it or a whole day when you figure in the novice factor.
Tips for @testingthewaters91 - use 3m 4200 sealant (NOT 5200 - that’s only for things you will never need to remove) and if the old sealant doesn’t want to let go heat the metal fitting with a torch.
Thanks, the contractor at the boatyard was recommending me to replace the wood with PVC backing, but to keep the seacock thru hulls because he feels they're not a risk and it would be a waste of money to replace them. I'm not concerned about money at the moment. I've got 4 Seacocks on my Hunter 30.
 
Jun 14, 2025
42
Hunter 1981 30 Chesapeake
Great article - that’s the ideal way to do it. However, if you’re just daysailing and vacation cruising in the Chesapeake you can use bronze or Marelon ball valves instead of bronze sea cocks.
I'll be living aboard for several months at a time when not working. Not sailing hard or anything. Mostly just Chesapeake and ICW.
 
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Jun 14, 2010
2,326
Robertson & Caine 2017 Leopard 40 CT
I'll be living aboard for several months at a time when not working. Not sailing hard or anything. Mostly just Chesapeake and ICW.
Still OK IMHO. If you plan to cross oceans I’d rather have proper seacocks but ball valves are just fine if properly installed and you know they’re in good shape.
 
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Likes: BigEasy
Jun 14, 2025
42
Hunter 1981 30 Chesapeake
Still OK IMHO. If you plan to cross oceans I’d rather have proper seacocks but ball valves are just fine if properly installed and you know they’re in good shape.
Okay, thinking about inspection of the current thru hulls. Will take a knife and hammer to them and see if they are brittle or weak. Any other methods to be sure?

If they pass all the tests, maybe I'll just put them on PVC backing as the contractor recommended and keep the thru hulls.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,070
CAL 35 Cruiser #21 moored EVERETT WA
Not sailing hard or anything.
It is not the sailing hard... it is the saltwater corrosion that occurs hidden from eyesight. They corrode from the inside and can simply fall apart.
If you are going to take a chance, at least get some emergency wooden plugs to fill the hole should one of them start to leak.
1750809729651.png
 
Jun 14, 2010
2,326
Robertson & Caine 2017 Leopard 40 CT
Thanks, the contractor at the boatyard was recommending me to replace the wood with PVC backing, but to keep the seacock thru hulls because he feels they're not a risk and it would be a waste of money to replace them. I'm not concerned about money at the moment. I've got 4 Seacocks on my Hunter 30.
If you replace the wood do not use PVC or ”King Starboard” use fiberglass sheet such as G10. Those plastic materials are too easily deformed and sealant does not bond to them. Wood is easier and cheaper to get and easier to cut/shape. Oak or teak, or even marine ply are acceptable if fully coated and sealed in epoxy.