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Bum Steer - rudder gland question
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. 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 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. 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 Morgan 461 #2 SV Flying Pig KI4MPC See our galleries at www.justpickone.org/skip/gallery ! Follow us at http://groups.yahoo.com/group/TheFlyingPigLog and/or http://groups.google.com/group/flyingpiglog I expect to pass this way but once; any good therefore that I can do, or any kindness that I can show to any fellow creature, let me do it now. Let me not defer or neglect it, for I shall not pass this way again. - Etienne Griellet |
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