Seacock Lubrication Tip


The ice has finally gone out of our inlet here at Base Camp and we are getting Morgan’s Cloud ready for launching. Here’s a neat tip that my friend Bob (a fellow charter member of the anal retentive boat owner’s club) taught me.

Why You Should

Metal seacocks should be lubricated every year before launching. If you don’t grease them they will eventually seize up, and since Mr Murphy is always in charge at sea, you will find that state of affairs when you try to close the seacock after a large water hose ruptures.

It’s even worth lubricating the relatively new “maintenance-free” seacocks—those with teflon mating surfaces. Why? Well teflon (PTFE) is also manufactured with oil imbedded as an additional lubricant, but that’s not what they use for seacocks. The point being that if teflon is good, greased teflon is better.

Even if your seacocks don’t seize up, if you don’t lubricate them they will eventually stiffen up so that when working them open and closed you will be putting a huge load on the mating surfaces where the actuating shaft (that connects to the handle) and the ball bear on each other. Eventually, slop will develop in this area and the ball won’t fully close-off the seacock—a scary problem since we might assume a seacock is closed to the deep blue when, in fact, it’s not.

As an aside, the seacocks on a lot of older boats have this problem, and so we should all check for it regularly and look carefully. We have had to replace two seacocks on Morgan’s Cloud for just this reason, that looked and worked fine on casual inspection.

The Hard Way(s)

OK, now we know we have to lubricate, but how exactly do we go about doing that?

Sure we could pull the hoses off to lubricate the ball by squirting a spray lubricant in with the seacock closed…lots of luck with that. Ever tried getting a large hose off a tail pipe it’s been clamped to for even just a year? Good way to burst a blood vessel.

Or we could squirt some spray lubricant in from outside, but it will drip all over our boat’s newly painted bottom.

Worse still, some spray lubricants contain solvents that will dissolve bottom paint. How do I know this? Well, it wasn’t pretty, and resulted in a lot of sanding and repainting.

And anyway, spray lubricant won’t last long.

Some seacocks have a plug you can remove—ostensibly there for draining, which is, if you think about it, a pretty useless “feature” for most of us since said seacock will drain when you open it. But you could temporarily replace said plug with a zirk fitting and use a grease gun. What a hassle.

The Easy Way

Or you could do it Bob’s-Easy-Way:

  1. Close all the seacocks.
  2. Paint the balls from outside the boat with Lubriplate 130-AA grease, which lasts great underwater, using an acid brush (see photo above).
  3. Work the seacock through its entire travel a few times.
  4. Repeat as necessary.

The above process is faster and easier with two people, one working the seacock from inside the boat and the other outside the boat painting the balls.

One caveat: If you have the old fashioned seacocks with the tapered cylinders, you should probably completely disassemble them for service every three years or so since they depend on a clean well-greased mating surface on the cylinder and casing to remain waterproof. Having said that, Bob’s trick will work fine for the interim years.

Thank you, Bob.


Do you have any cool pre-launch maintenance tips? ‘Tis the season, at least for us northern residents. Please leave a comment.

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