Let's Talk Seacock

[Dockhead]

Your setup is OK except for two things:

1. The fittings are likely to be brass (the markings indicate land purposes). You want 85-5-5-5 bronze; insist on it and accept no substitute.
2. The through-hull fittings are too long, leaving too much thread exposed.

And possibly one other thing:

3. If those are NPT fittings (as opposed to the rest of the world BPT/BPS standard fittings) you may have a thread mismatch, which is not good.

If you get good quality bronze through hull fitting with properly matched bronze ball valve, you don't need the flange. The cultists will cry that "you will die!" but virtually 100% of European boats are built that way, and no one dies, and that includes the best boats in the planet, namely Oyster, Discovery, Contest, Swan, HR, etc.

The Groco flange shown in some of the posts above will solve any thread mismatch problem and will make the assembly somewhat stronger, but you have to drill three extra holes through the hull in each through hull position, protect the core properly if there is coring there, etc., etc., etc. I would never do that myself -- immense amount of trouble, plus added risks to the boat's core, for slight gain of strength. But to each his own, and you will have to make up your own mind.



Another thing I don't like about the flange is that it adds one more joint to the assembly, and you can't inspect the through-hull fitting without pulling the flange off. How many people with those flanges have ever pulled them completely apart to inspect the through hull fitting for dezincification or other deterioration? I'm guessing it's an even zero. And that is not good!! Also the length of the through hull fitting becomes absolutely critical, and how likely are you to get it exactly right? Sorry to the cultists, but I just do not like these.


If you go without the flange, Groco makes matching throughhulls and ball valves, or you can simply use BPS/BPT fittings which don't have this problem.

Use top quality bronze fittings, though, whatever you do! Groco is good; in Europe we use Maestrini which are excellent, and you might be able to get them where you are.

And make sure the through hulls are the right length, not to leave too much threaded part exposed, and make damn sure that the ball valves thread down with at least however many turns -- I forget -- I think 5 or 6. Otherwise the assembly won't be strong enough.

[Bowdrie]

Originally Posted by Dockhead

If you get good quality bronze through hull fitting with properly matched bronze ball valve, you don't need the flange.

Like many devices on a boat, all is fine when products are newly installed.
The downside of the valve screwed directly on the thru hull appears when the time comes to replace the valve.
No, it doesn't happen all the time, but I've experienced it on more than one occasion whilst working on other boats.
You go to unscrew the valve and the thru hull rotates in the hull, now the adhesive seal is broken.
If there is not enough exposed thread on the thru hull that you can grasp with a pair of narrow jaw "water pump" pliers you're in a bad situation.
Then the job becomes a two-man job with the boat hauled out.
If in the water, well, now things have become more complicated.
IIRC the Groco flanges are available with both thread standards, and testing has shown that the strength of the assembly FAR exceeds the term "somewhat".
And thru hulls can be checked/replaced/changed without any disturbance of the flange or valve.
It's a no-brainer, no matter what was originally used.

[gonesail]

i have the older Spartan Marine bronze seacocks. one of them was stuck and during a haul out .. i removed the cone for lapping and was surprised to see that the bronze was in good shape after 30 years. greased it and carefully put it back together. now operates with one finger and no leaks.

[stormalong]

Skip the bronze quality dilemma - Go to plastic. Marelon or Truedesign. No corrosion worries. No maintenance other than turning the valve from time to time.

Before a certain individual chimes in be aware that there was a problem with Marelon 30+ years ago. Handles would break off. That problem was solved way back then.

[Dockhead]

Originally Posted by Bowdrie

Like many devices on a boat, all is fine when products are newly installed.
The downside of the valve screwed directly on the thru hull appears when the time comes to replace the valve.
No, it doesn't happen all the time, but I've experienced it on more than one occasion whilst working on other boats.
You go to unscrew the valve and the thru hull rotates in the hull, now the adhesive seal is broken.
If there is not enough exposed thread on the thru hull that you can grasp with a pair of narrow jaw "water pump" pliers you're in a bad situation.
Then the job becomes a two-man job with the boat hauled out.
If in the water, well, now things have become more complicated.
IIRC the Groco flanges are available with both thread standards, and testing has shown that the strength of the assembly FAR exceeds the term "somewhat".
And thru hulls can be checked/replaced/changed without any disturbance of the flange or valve.
It's a no-brainer, no matter what was originally used.

Yes, breaking the seal of the mushroom fitting when removing a directly attached ball valve is certainly a risk of that type of installation, and it's happened to me. It's rare if everything is installed correctly (really well bedded-in mushroom valve; properly doped and not over-tightened ball valve joint; properly cinched down lock nut), and anyway you don't do this with the boat in the water. Most important is that the lock nut is tighter than the ball valve.

But how do you inspect the mushroom fitting for dezincification or deterioration if it's screwed into a Groco flange adapter? Only by taking the whole thing completely apart from the top, unless I'm missing something. Either that or unscrewing the fitting from the bottom, breaking the seal, then rebedding it afterwards. Ugh.

[Nicholson58]

Originally Posted by Jammer

Depends on whether you're a member of The Cult.

https://www.cruisersforum.com/forums...ll-267705.html


The "gold standard" has, traditionally, been flanged seacocks through-bolted to the hull, or attached using studs embedded in the hull. Bring money, and allow a couple of hours of quality time with epoxy and G10 board per seacock. Budget for some extra drill bits and hole saws, the G10 will dull them after a couple of cuts.

Remove the 1/8 NPT plug in the valve body and screw in a Zerk grease fitting and add grease whenever.

[Bowdrie]

Originally Posted by Dockhead

But how do you inspect the mushroom fitting for dezincification or deterioration if it's screwed into a Groco flange adapter? Only by taking the whole thing completely apart from the top, unless I'm missing something. Either that or unscrewing the fitting from the bottom, breaking the seal, then rebedding it afterwards. Ugh.

No need to take apart the assembly.
If the adaptor flange, (or a real seacock, like a "Spartan",) is properly thru-bolted to the hull, (or embedded nuts/studs.) and installed on a G10 pad with your favorite sealant, and that pad is bedded to the hull in thickened epoxy, you simply unscrew the mushroom fitting/thru-hull.
Truth be told, with the hole in the fiberglass laminate being well sealed with epoxy, (to prevent any water from wicking into the laminate,) and a bolted flange, you don't even need a mushroom fitting.
You DON"T use the thru-hull/mushroom fitting as a means of securing the flange to the boat.

[Pegu Club]

Originally Posted by Jammer

Depends on whether you're a member of The Cult.

https://www.cruisersforum.com/forums...ll-267705.html


The "gold standard" has, traditionally, been flanged seacocks through-bolted to the hull, or attached using studs embedded in the hull. Bring money, and allow a couple of hours of quality time with epoxy and G10 board per seacock. Budget for some extra drill bits and hole saws, the G10 will dull them after a couple of cuts.

This right here ^^^

If one is to replace thru hulls and seacocks do it right so you only have to do it once.

Fair winds,

[bcboomer]

+1 for Trudesign.
I've had them for 10 years and they never get stiff to turn.
No maintenance and no concern about stray current.

If you have a boat with older bronze how can you be sure it hasn't been compromised?

[CharmCityBoater]

I am a convert and true believer that TruDesign (specifically) is a much better alternative to Bronze. Bronze has its place, however, TruDesign covers 90% of the needs. When you use their ABYC compliant load bearing collars and install them properly they are pretty bulletproof. No corrosion. Still need maintenance, they all do.

There is always a group of people that say "It has to be bronze, it is stronger and better...". I no longer buy that. TruDesign has proven itself. Not a fan of Marelon fittings though.

YMMV.

Phil

[bcboomer]

Originally Posted by CharmCityBoater

Still need maintenance, they all do.

Phil

Hi Phil,
What maintenance do you do?
I have 1 that sat 9 years in the closed position until I added the water maker.
It wasn't stiff at all.

[SOLAR SUPPORT]

In addition to the subject of material selection, I think it is worthwhile to mention the use of ball valves and their long-term waiting position.

Valves whose outlet is under the water line are usually kept closed during long waiting periods. This is the right thing from a security standpoint. It is inevitable that the surface of the valve ball facing the sea outlet will stick to the surface of hard formations such as thyme etc. within a few months.

When you try to open the valve, which has been kept in the closed position for a long time, you will see that the force applied to the arm increases. There are two reasons for this, the first of which I explained above. The second is the increased pitting formations in the valve, especially since there is no oxygen circulation in the sea water trapped between the valve sphere and the valve body for long period of time.

In order to reduce both effects, it may be considered to leave the valve in the open position which is in a solid and reliable condition. Pitting oxidation will be prevented, especially if the valve is left in the half-open position in a controlled manner while sailing. It is also helpful to move the valve handle between fully open and fully closed positions during each visit to the boat.

[DeValency]

Three years ago, I replaced all 15 through-hull fittings and sea cocks with TruDesign composites. Zero maintenance and issues since. Will never go back to bronze.

[Alita49DS]

Forget the ancient technology. Other than as a rather geeky ornament on a shelf at home.

I am another fan of TruDesign. Fit and forget.

[Dockhead]

I have found that with good quality ball valves, it is enough to operate the valves regularly.

The new Maestroni ball valves have composite, not metal balls, btw.