Proper installation of sea cocks

[MarkSF]

My Bristol has about 10 Wilcox-Crittenden "Seacox" and I need to start replacing them, as they are all either too stiff or leak (or both!) Well, the problem seems to be that if you tighten them up enough not to leak, they don't turn!

I was looking at the instructions for installation of Groco seacocks, and they say that the base plate should be bolted through the hull, or at least to a base block of wood, don't just rely on the through-hull mushroom.

None of the "Seacox" Bristol installed are through-bolted (despite having the holes in the base), and neither does a newer Groco one for the engine intake, installed by a reputable boatyard 2 years ago. There's a huge amount of white goo around it though.

So my questions are, how are seacocks normally installed. Is the through-bolting necessary, and if so, why didn't Bristol or the boatyard do it? Time & cost? I would expect the boatyard at least would be only too happy to bill for the extra labour involved in through-bolting the seacock.

[brpyrate]

My Rule is:
ANY hole in the Hull is Capable of Sinking the Hull,if it leaks.
SO Openings in the Hull, Especially below the Waterline,should be Stronger than
the surrounding Hull itself.

Backing Plates,Large.
Then there's the whole Religion of Galvanic/Chemical Corrosion with fittings.
Another Religion> Sealants.
[I like 4200,it's removable By Humans in a single lifetime.]

Is the White Goo oozing out from your newly installed Seacock, Removable?
(A few minutes with a Dental Pic will tell)
If it's not It's 5200 and that's why the Yard didn't bother with PROPER Installation.
(They think 5200 is ONLY removable AFTER the Second Coming)

I wouldn't drill two or four additional Holes in the Hull for Seacock Base Plate Through Bolts.
(Remember:Less Openings = Happier Sailors)
I would use a LARGE base Plate in between the inside of the Hull and the Seacock "Mushroom".
(Example: for a one inch Pipe,a 5 inch (on each side) square Base plate with mucho 4200)

[And ,YES silly me I'd use Stain-Less for the Base plate.]

[eherlihy]

All about seacocks HERE READ THIS FIRST

One way to replace them (through bolting) HERE

Alternative way (no through bolting - and the way I did mine) HERE

[tommays]

I believe from reading Mainsails stuff the old ones can be laped to stop the leaks and work well again

[SloopJonB]

Originally Posted by tommays

I believe from reading Mainsails stuff the old ones can be laped to stop the leaks and work well again

True, as long as they haven't become wasp-waisted. You simply disassemble them, check the "barrel" to ensure it is true then put a little lapping compound on them and start rotating them. Periodically wipe clean to check the pattern of lapping - you will know when you are done. These things are pretty ancient solid bronze technology which should outlive you and several generations of your descendents if they are properly maintained.

Personally, I'd be more worried about the NUMBER of them. 10 big holes in the bottom sounds excessive. I'd be looking for some way to minimize their number so I could glass over the holes.

P.S. - this style of valve needs a little grease on the barrel to seal properly.

[MarkSF]

Originally Posted by eherlihy

All about seacocks HERE READ THIS FIRST

One way to replace them (through bolting) HERE

Alternative way (no through bolting - and the way I did mine) HERE

Thanks! Very informative.

[MarkSF]

Originally Posted by SloopJonB

True, as long as they haven't become wasp-waisted. You simply disassemble them, check the "barrel" to ensure it is true then put a little lapping compound on them and start rotating them. Periodically wipe clean to check the pattern of lapping - you will know when you are done. These things are pretty ancient solid bronze technology which should outlive you and several generations of your descendents if they are properly maintained.

Personally, I'd be more worried about the NUMBER of them. 10 big holes in the bottom sounds excessive. I'd be looking for some way to minimize their number so I could glass over the holes.

P.S. - this style of valve needs a little grease on the barrel to seal properly.

It's the maintenance that is the problem. Pulling the boat out of the water once a year to re-lap and re-grease the seacocks is not very practical.

Not so much I can do about the 10 holes, unless I live without some of the scuppers (6 holes for those... 2 cockpit, 4 gunwhales)

[PorFin]

Originally Posted by SloopJonB

Personally, I'd be more worried about the NUMBER of them. 10 big holes in the bottom sounds excessive. I'd be looking for some way to minimize their number so I could glass over the holes.

Maybe so, maybe no -- depends on function and location.

I've got a bunch of holes myself, but only a couple are redundant enough to consider filling.

I've got 4 well below the waterline:
- Engine r/w intake.
- Head r/w intake.
- Galley/watermaker r/w intake.
- A/C r/w intake.

I've got 8 along the bootstripe (sometimes underwater, sometimes not so seacocks are prudent ):
- 2 x cockpit scuppers.
- 2 x deck drains.
- Galley sink drain.
- Head sink drain.
- Head direct discharge.
- Macerator discharge.

That's twelve, not including the two depth/speed/temp transducer fittings - the second one is the only thing I'd seriously consider taking the effort to fill, but it seals just fine with the blanking plug in place. Some could be relocated higher, but that's kind of a solution looking for a problem.

Back to the OP -- try overhauling your existing seacocks before you replace them. At worst, you're out the cost of a bit of valve grinding paste and some quality time that you're investing into Vigor's "black box."

[PorFin]

Originally Posted by MarkSF

It's the maintenance that is the problem. Pulling the boat out of the water once a year to re-lap and re-grease the seacocks is not very practical.

You can do this in the water -- just plug the t/h from the outside (but don't forget to unplug it when you're done...)

Once a year would be excessive -- it's finally time do so this and they're how old now?

[Ilenart]

I read with interest the requirement for bolting thru hulls as I am right in the middle of changing some seacocks. Unfortunately I have found it is impossible to locate any thru hull fittings which "bolt on" here in Oz; All the fittings sold are like these ones here.

I then dug out my latest "bible" on such matters, Nigel Calder's Boatowner's Mechanical & Electrical Manual (3rd Ed) and was interested to read the following:

At one time the ABYC required seacocks to have flanges that could be securely (ie independently) fastened to the hull. This is no longer part of any standard, although many bronze seacocks are still installed in this manner.

Therefore it appears that a thru hull without "bolts" is acceptable, I assume because utilsing Sikaflex 291 or similar creates a bond which is just as strong as bolting.

Comments/ thoughts?

Ilenart