On Wed, 7 Mar 2012 16:56:13 -0500, "Flying Pig"
wrote:

Bum Steer - rudder gland question

Hi, all,

My rudder post is badly pitted in the area near the packing gland. The pits
cut the teflon flax packing and, eventually, no amount of tightening will
prevent water running through, and, all along, more comes than it should.

If you're interested, you can see what I mean about the pits by clicking the
gallery link below, and then clicking through the 2011 refit and rudder
project. I've got pictures of everything to this point; see my
dissatisfactions below...

Dropping the rudder isn't a good option, so even if in the unlikely event
(because I've already been doing exploratory searching - if I were SURE a
shop could handle it, I'd drop it) I could find some machine shop which
could attack the problem by grinding, welding, and then cutting back to
size, I did the best I could, which was to thoroughly clean the pitted area,
including an acetone wash, and then apply epoxy in and over the pits. That
was followed by reducing all the excess epoxy to the level of the good
metal.

That is a bad idea, if for no other reason then it is probably
impossible to weld on a shaft without getting some warping. If there
wasn't that big ugly appendage on the end of the shaft then warping
would be a minor problem as you could just put the shaft in a press
and straighten it but more then likely that the rudder is going to get
in the way.

I'm not concerned about the strength of the post, as it's solid 2" SS rod.
That there are 1/2" keyways cut in the top of it - 2 for 6 inches, and one
of them continues for over a foot - suggests that it could easily work at
only 1.75" - Waaay less than the bottom of the worst pit.

The "pitting" appears to be crack corrosion and will undoubtedly get
worse as time goes by.

The pits didn't fill entirely with epoxy, but it's a lot less cavities
and/or much more shallow than were present before. However, I'm sure that
some of the same problem would remain - the pits would chew up the teflon
flax, albeit at a slower rate, and we'd be not much better off. I went back
and did it again, letting the epoxy thicken a bit before application

What you see with the blue tape and the vaseline was to prevent epoxy from
sticking to the tube. Unfortunately, I didn't make a dam with it, and a
fair amount dribbled into the tube. Aggressive working of the rudder, back
and forth, from stop-to-stop (far more than the steering mechanism takes it,
enabled by the steering being off) scrubbed all the resistance off, helped
by a few drops of 3-In-One oil as I went, and it now turns freely. So, the
second time, I did a couple of things differently:

First, of course, I wire brushed it again to scuff up the epoxy which is in
the pits so far. Then I made sure that the vaseline made a dam around
the entire bottom. And, finally, I didn't put any epoxy on until it was a
great deal thicker than it was the first time. We're in "warm" weather, but
far from "hot" - so the slow hardener I have gives me a lot of time to work
with it - but also a lot of time to wait until it's more viscous.

It actually took three times to get it to where I'm happy with the fill
level. With any luck, that will hold in place. But the nature of the beast
is that either the tube was too big, or has worn over the years, so the
shaft isn't tight against the sides, even with my centering the rudder. That
makes for some pressure points (as the lever-action weight of the rudder
moves the shaft against the packing in different areas), which I'm sure will
eventually make the gland leak more than it should.

However, I've had identical suggestions, separately, by two very
knowledgeable sources, to pack the gland with heavy grease, as well as the
5/16" teflon flax I've just repacked it with. Both suggested drilling and
tapping to allow insertion of a zerk. However, as you may be able to see
from the pictures, that would be difficult at best, would inevitably hit the
post in order to get deep enough, and likely the only possible point would
be very near the bottom, suggesting that most of it would come out at the
hull, rather than going back up the tube. So, instead...

I had to take everything off the top - a major steering assembly, autopilot
and rudder position indicator arms, and the packing nut - to get to the area
I was working on effectively, so it will be an easy proposition to get
access for the 1" of vertical height x ~1/4 inch of grease which I can lay
on without having it start squishing into other spaces before my threads on
the packing nut engage.

Sometimes doing something right takes what seems like more effort then
doing it easily, if one discounts the fact that the easy way almost
always involves having to do it over.

The grease will get forced down the stern tube, and, I'm sure, until I get
it very tight, up the flax cylinder which makes up the actual bearing. It's
been suggested that if this area - under the packing gland, in the stern
tube, and into the flax as well - is solid grease, with the very slow turn
rate of the rudder post, there will be no "tight" or friction issues due to
lack of water, and not the first drop of water will ever make it out of the
gland.

So, my first question is:

Have any of you done this, and if so, to what result? Does it, in fact,
inhibit the passage of water due to the pressure of water further packing
the grease against the shaft, or does it just make an ungodly mess either
before, during, or after use and during packing replacement on the next time
around? I have visions of grease slowly working its way through and out the
top, making it very sloppy under our bed, which is where the rudder post
lives, VERY inaccessibly when the steering is attached, and then,
eventually, letting water through, however that might be...

Related, if this is such a big and easy success, why is it that rudder tubes
don't arrive with these zerks and instructions on how to use them??? Of
course, mine would be without the zerk, but I can't see that grease could go
anywhere other than out the top if it were needing replacement (it would
float, let alone be held up by pressure, so not go out the bottom other than
by overflow when greasing), and, if the packing were AT ALL tight, I would
expect it wouldn't make it through, the viscosity of the grease being so
much more than water.

Finally, if you've done this, what grease did you use?

A second suggestion, by a merchant mariner who swears his crew did it on
many different occasions on a variety of rotating shafts which were pitted
is this: Take a very hard plastic tube of the right ID such that it can be
tightly slipped over the rudder post. Turn it down to a size which will
accommodate passage through the packing gland. Lubricate with a very light
lube and slip it down onto the pitted area. Reinstall packing and tighten.

He claims that the sleeve, being relatively softer than the metal, takes the
beating and the pits fill up with the plastic, while the packing gland keeps
it all tight but allows the post to turn - and it lasts for years.

My mind can't quite wrap itself around that, in that I can't see how the
hard plastic will do a better job than teflon flax packing at keeping the
water in - it seems to me the water would be more easily able to come up
through the pits with plastic against it rather than the packing material.

Further, as the first set of pix currently up in the gallery will show, the
pits in the area contacted by the packing were, indeed, full of packing
(until I cleaned them out) - so, apparently, filling the pits with something
else isn't the entire answer.

So, in this case, have any of you ever actually done THIS type of
workaround, and, does it, indeed, work?

Thanks.

L8R

Skip

There are several possible cures.

They used to, and likely still do, make a "dripless" gland packing
that was some sort of soft plastic substance what you packed the
bearing with. It "squished" enough to make the gland waterproof and
seemed to stay in place for years. West Marine used to sell it, and of
course it was available elsewhere. Used in a rudder shaft gland as
apposed to a propeller shaft gland it might be satisfactory.

They make a black impregnated packing that the seal shop that I
patronize tells me will last for years even on a pitted shaft. I used
it on a pitted propeller shaft on a power boat and a trip from
Singapore to Phuket, Thailand didn't show any leakage.

Years ago stuffing boxes with a lubrication system were common. Often
times with a "grease cup", but sometimes with a simple zerk fitting it
allowed injection of grease to lubricate the old time flax packing. If
one injected waterproof grease periodically it would likely reduce or
eliminate leakage.

See drawing of gland: http://royalpurpleindustrial.com/prodsi/cap.html
Better lubrication: http://www.gouldspumps.com/pag_0011.html

Finally: while, of course, the ultimate solution is to replace the
rudder & shaft assembly :-( is it possible to rebuild the packing
gland installation so that the gland falls above the damaged area?
With a hose perhaps, similar to most propeller shaft glands?

I can't see, but is the gland acting as an upper shaft "bearing", if
not, it might be possible to make an extension for the present shaft
that clamps on the top of the shaft to mount the quadrant and various
rudder indicating senders and simply raise the stuffing box.

Of course, the ultimate fact is that whatever you do, other then
sticking more whatever in the gland, which didn't work, any final
solution you decide on will probably cost you money.

Addendum: I just happened to think of one more possible solution. You
might try shrinking a section of "shrink tubing" over the shaft in the
gland area. this is a shrinkable plastic sleeve used to insulate and
waterproof electrical connections. Initially it is large enough to
slip over the joint and then you shrink it by heating with a hot air
gun. Comes in 3 foot lengths, I believe.

If you use it do go to a commercial electrical shop and get the type
with the glue inside - they will know what you are talking about. It
is much more robust then the hobby shope stuff. Be aware though that
the industrial stuff takes either a commercial hot air gun or a gas
torch to shrink. Not the hair drier like the hobby shop stuff.
--
Cheers,

Bruce