Differing advice--can someone clarify?

[FrankLanger]

In reading about seacock maintenance, I am reading and hearing that seacocks require annual lubrication, but ball valves are relatively maintenance free. I had thought that ball valves are a kind of mechanism in the seacock, not a different fitting altogether. And I can't understand why a seacock needs annual maintenance, but a ball valve doesn't. Is there anything that a ball valve does need, other than regular operation to ensure it still works?

I am not talking about gate valves, which I understand are bad on a boat because one can't tell if they are open or closed, and apparently they aren't as reliable.

Thanks for any clarification.

Frank.

[sailingdog]

There are three types of valves used as seacocks on boats. They are:

gate valves...which are a really bad idea
ball valve...which are becoming the norm nowadays
tapered cone... which are becoming a bit scarcer as of late

All of them, including ball valves, will generally require annual maintenance of greasing or lubricating the mechanism. Most will require at least monthly operation to prevent them from seizing in a given position.

The real reason gate valves are such a bad idea on a boat, is the gate can fail and even though you think you've closed the valve, and turned the handle all the way shut...the inner part may still be open. That can't happen with a ball valve or tapered cone valve. So you may be starting work on a hose, and shut the valve, and when you remove the hose, the through-hull is still pouring water into the boat...

[FrankLanger]

Thanks, Sailingdog. For the ball valve, is there any way to grease/lubricate it without taking the hose off (I don't like the idea of undoing a non-leaking fitting as with my luck it will encourage it to leak afterwards). Can it be done by pouring a bit of vegetable oil down the drain or flushing a small amount of vegetable oil through the head? Can it be done from the outside during a haulout?

Or do I need to "bit the bullet" and take the hose off, apply grease, reattach the hose and then work it to spread the grease on the ball valve?

Thanks,
Frank.

[sailingdog]

You can do it from outside the boat, by putting grease on the end of stick and putting that into the through-hull. You really should have someone on the inside of the boat to work the valve while you hold the grease against the ball. This can even be done with the boat in the water, but you'll probably want a scuba tank and mask if you're doing that. You really need to use a grease, an oil is too thin and won't lubricate the valve seat properly. IIRC, Lanocote can also be used.

[LarryandSusanMacDonald]

Here at the Yacht Yard where I work, frequently customers will request that their seacocks be lubricated when we pull them. If they are ball valves (the norm these days) we use two guys - one on the inside, one on the outside. The guy on the inside works it back and forth while the guy on the outside sprays with silicon lubricant.

More than once, the poor guy on the outside got a shower from a holding tank, so be careful which seacock you're opening.

If the seacock does not operate smoothly, we dissassemble and repair, or replace if necessary.

We have found that most of the time when the bronze seacock is green - badly green - it has suffered from galvanic corrosion. It is ALWAYS bonded when it is green - which is why I don't like bonding in a boat. Most of the guys in the boat yard agree. The rest don't know what they're talking about.

The tapered cone style we almost always dissassemble and lubricate with a lubricant which looks a little like library paste and comes in a 5 gallon bucket. I forget what the stuff is called. I haven't done it a long time.

[camaraderie]

Or buy good Marelon seacocks! Actually the whole annual maaintenance thing on through hulls is way overblown. It comes from the fact that MOST boasts sit at the dock and the through hulls don't get excercised and get clogged up and stiff with disuse and with barnacles etc.
If you are using your boat and working the through hulls regularly and they are operating smoothly, just keep em cleaned out from barnacles etc. which you can do from the water with a hanger wire. If they start feeling a bit stiffer or if you are hauled and it has been a couple of years..then you might add a bit of grease...and as dawg says...you can do it easily from below if you have someone work the lever while you work the gun.

[Faster]

Hopefully this isnt considered a hijack, Frank....

Our current boat has tapered cone thruhulls throughout, with the exception of the cockpit drains which had been gates and I've changed to ball valves.

How much of the "seal" on these tapered cones is provided by the grease? Mine do not hold well (they seep if I remove the hose), but if I tighten the gland any further I can't move them easily. - I'd also be interested to know the best grease to apply on the next haulout.

Thanks

[JohnRPollard]

Originally Posted by sailingdog

All of them, including ball valves, will generally require annual maintenance of greasing or lubricating the mechanism. Most will require at least monthly operation to prevent them from seizing in a given position.

In my experience annual maintenance (greasing or lubricating) would be over-kill for bronze ball valves.

I last lubed our seacocks (bronze ball valves) five years ago and they still open and close easily. Our boat is typically in the water 11+ months a year. Maybe the fact that we open/close them all when we come and go from the boat has something to do with it...?

[chucklesR]

Faster,
Tthe best grease is what you apply to the yard workers palm when he replaces the cone seacock with a marelon ball type seacock. After that, if you insist - Lithium marine grease stands up well to the test of time.

[chucklesR]

IIRC, the best cleaner for bronze deck drains, valves etc is good old fashioned Navy koolaid, which we called bug juice. It literally works as a mild acid and removes any gunk that has built up.