Seacock warning, probably most relevant to Australians

[Cpt Pat]

Originally Posted by El Pinguino

PS.... the ones on their site are branded... they are 'CHINA' brand.....
https://www.whitworths.com.au/bronze-ball-valve

Then it wasn't bronze. It was Chinesium (brass-plated pewter or some other cheap metal).

All through-hulls are evil. I eliminated all but three on my boat (two cockpit drains and one rudder post) after the internal seal failed inside a wonderful bronze ball valve one night and I had to go over the side to stuff epoxy putty into the below-the-waterline port. Single-handed.

Plumber's epoxy putty is great stuff. It cures underwater. Just hold it in place for 60 seconds. I have no idea how to hammer a bung into a hole under water at night in 8 foot swells.

[GILow]

Originally Posted by Wotname

Curious, what is the galvanic circuit when using un-bonded seacocks?

Shhh. You’ll spoil the fun.

[GILow]

Originally Posted by Cpt Pat

I have no idea how to hammer a bung into a hole under water at night in 8 foot swells.

With great difficulty I suspect.

[er9]

Originally Posted by Oceansailor

Bronze seacocks fail as they are not 100% bronze. More or less all manufacturers uses a brass stem and a brass ball in a bronze housing. The brass parts acts as an anode and corrodes. Stem breaks and you get the handle in your hand. If anyone knows a manufacturer that actually do not use brass parts I’m interested. I have so far not been able to find anyone....

Spartan Marine's bronze seacocks are tapered cone not ball valve. 100% bronze through and through. I think Apollo makes tapered cone as well but I may be mistaken. I have 40 year old tapered cone bronze seacocks on my boat and they are all in near perfect condition. all you have to do is re-lap them with lapping compound every decade or so.

[Wayfarer111]

Interesting reading, thanks to all for furthering my education

er9 i hadn't thought of lapping the ball valves, this would seem IMHO to be a good solution for tight valves. Mine were out recently (just a few that are above the waterline) and i simply sanded them clean, lubed and replaced .....they are still tight

actually can anyone identify them, they are all the original fittings and seem to be going strong at 35yrs of age. All i can see is a "made in Sweden" in the casting.

ps, sorry for the pic that will not rotate

[George DuBose]

Cheap seacocks are available world-wide. Some manufacturers are installing them in new builds. The EU requires that seacocks be changed every five years.

My 1973 Pearson came with massive marine bronze seacocks made by Wilcox-Crittenden. After 46 years, they are as good as new. Whenever I see these W-C seacocks on eBay, I buy them.

Brass or plastic, neither are as strong as the older models. Spartan and Groco still make quality hardware.

Buy cheap tools, buy them twice.

[Dockhead]

Originally Posted by s/v Jedi

+1 people need to check that out. It includes my recommendation for flanged adapters.

What is the point, exactly, of the flange there?


It would not increase strength in the ABYC test because the ball valve is supported by the same threaded neck which is the weak point with an ordinary mushroom headed skin fitting. I notice that MaineSail tested some Groco mushroom headed skin fittings but not any flanged ones.


This would be a different matter: .


This would be stronger because there is no threaded neck; the ball valve is directly supported by the flange. However I'm not sure why this much strength is needed.



I'm open minded about this, but I'm struggling to see the point of any of these. They are not used by European builders even on multi-million euro boats.

[s/v Jedi]

Originally Posted by Dockhead

What is the point, exactly, of the flange there?


It would not increase strength in the ABYC test because the ball valve is supported by the same threaded neck which is the weak point with an ordinary mushroom headed skin fitting. I notice that MaineSail tested some Groco mushroom headed skin fittings but not any flanged ones.


This would be a different matter: Attachment 207710.


This would be stronger because there is no threaded neck; the ball valve is directly supported by the flange. However I'm not sure why this much strength is needed.



I'm open minded about this, but I'm struggling to see the point of any of these. They are not used by European builders even on multi-million euro boats.

The threaded part that the ball valve attaches to is not the through hull fitting. The fitting has linear thread and is rather weak as you write. It is cut to size and the flanged adapter is screwed onto it and fastened to the hull, completely protecting the skin fitting.
On top the flanged adapter has a tapered thread for the valve. It matches the tapered thread that valves have and it is much more substantial/stronger than a skin fitting. The big advantage is that the valve can simply be replaced with another one or even a bronze cap.

[Dockhead]

Originally Posted by s/v Jedi

The threaded part that the ball valve attaches to is not the through hull fitting. The fitting has linear thread and is rather weak as you write. It is cut to size and the flanged adapter is screwed onto it and fastened to the hull, completely protecting the skin fitting.
On top the flanged adapter has a tapered thread for the valve. It matches the tapered thread that valves have and it is much more substantial/stronger than a skin fitting. The big advantage is that the valve can simply be replaced with another one or even a bronze cap.

So just like a European mushroom skin fitting in function and probably in strength. Which seems adequate to me unless the fitting must be located somewhere where heavy objects might slam against it.



I guess the main purpose of the flange adapter is to eliminate the NPT/NPF problem with American fittings.

[s/v Jedi]

Originally Posted by Dockhead

So just like a European mushroom skin fitting in function and probably in strength.

No I don’t think so. Show me what kind of fitting you mean (I’m European but you must have something else in mind than what I know)

[Dockhead]

Originally Posted by s/v Jedi

No I don’t think so. Show me what kind of fitting you mean (I’m European but you must have something else in mind than what I know)

Well, the universal system in Europe:







https://www.asap-supplies.com/fittin...fitting-403108


https://www.asap-supplies.com/bronze...e-2-bsp-28910i


The flange adapter is not needed (and never used), because there is no thread mismatch problem -- everything is BSP.

[s/v Jedi]

Originally Posted by Dockhead

Well, the universal system in Europe:


Attachment 207716

Attachment 207717


https://www.asap-supplies.com/fittin...fitting-403108


https://www.asap-supplies.com/bronze...e-2-bsp-28910i


The flange adapter is not needed (and never used), because there is no thread mismatch problem -- everything is BSP.

Well if you like that then more power to you. In the US you get the same kind of nut for the skin fitting but it is considered unsuitable so a flanged adapter or a flanged seacocks is used. Something that attaches to the hull and takes all strain off the fitting. Many boats have had incidents or even sunk because they did not have a flange fastened.

BSP is a thing of horror when mismatches occur. In the Caribbean there are many who try to mate BSP thread with NPT or NPS and they strip out fittings, valves and end up with a leaking mess.

[Dockhead]

Originally Posted by s/v Jedi

Well if you like that then more power to you. In the US you get the same kind of nut for the skin fitting but it is considered unsuitable so a flanged adapter or a flanged seacocks is used. Something that attaches to the hull and takes all strain off the fitting. Many boats have had incidents or even sunk because they did not have a flange fastened.
. . .

I neither like nor dislike these but this is the universal system in Europe, used by Swan, HR, Contest, Oyster, etc. etc. etc. and it seems to work fine. I don't think I've ever heard of a boat sinking in European waters because a bronze skin fitting failed. Different matter is hoses and hose clamps, and those crappy brass fitting the mass builders were using, but that's a materials and not design issue.


The bronze skin fitting stuck through a few inches of GRP bottom, set in Sikaflex, and snugged down with that nut, is hella strong -- must be 10x or 100x stronger than the threaded neck, which is the obviously weak point. A flange which doesn't do away with the threaded neck couldn't possibly add any strength. Different matter of course would be an actual flanged sea cock where the whole ball valve is flanged -- that would be much stronger. But as I said, I'm not sure why that strength would be particularly needed.

[flee27]

Off topic a little bit but it makes me wonder why aren't sea chest used more for sea water needs. Seems like it would be safer to have one through hole/seacock to maintain and with just one, cost is not such a concern. If you ever have an unknown sea water leak just one valve to close to eliminate that problem. If water is still coming in you know you have a breach in the hull.

Thanks for the knowledge to those that know.

Foster

[Dockhead]

Originally Posted by flee27

Off topic a little bit but it makes me wonder why aren't sea chest used more for sea water needs. Seems like it would be safer to have one through hole/seacock to maintain and with just one, cost is not such a concern. If you ever have an unknown sea water leak just one valve to close to eliminate that problem. If water is still coming in you know you have a breach in the hull.

Thanks for the knowledge to those that know.

Foster

I am not one of "those who know" but rather one of "those who can guess and don't mind blathering about it"


Sea chest is a fairly complex construction on a plastic boat so it seems understandable to me that builders would prefer the much more straightforward approach of simply drilling holes and whacking skin fittings in.



Also sea chest might take care of engine room water intakes but you will still need ordinary skin fittings for everything else, so not a panacea.



May be different in metal boats, and in fact you do see them sometimes on metal boats. I've never personally seen one on a plastic boat other than an Amel.