Mon 17 May, HHN day 34: After yesterday’s storm, clean-up day of the rudder bearing… while pondering how to address seals and galvanic corrosion pitting issues.
After yesterday’s high activity, I expected to sleep well. But I was kept awake by a swollen and throbbing middle finger. No, this one is not a maintenance related injury. I stabbed the finger with Oana’s blunt kitchen knife while attempting to get a pip out of an avocado. Oana is right, I need to get back to my cocoon in Bucharest while I’m still alive and kicking.
Even so, I’m still up with the alarm. It is happening the same as last autumn: As I start counting down the days I have left, I get into a bit of a frenzy trying to finish everything on my list… or at least the key items. A boat’s to-do list, of course, can never actually be completed!
Today will be a clean-up day of the rudder bearing, and hopefully some direction as what to do about putting it back in.
I have the seal kit, so I could just clean up the pieces of rudder bearing assembly and throw it back in. And likely even have the rudder back in by the evening. But that’s not how I work. If I do that, the rudder will likely have to come off again before long. There are a few things to be worked out to stop that from happening. I, for one, do not want to see the rudder out again!
Firstly: was the lower seal installed the correct way around, or not? Ray, Paul and I waste a good hour debating.
It feels like Hallberg-Rassy installed it the wrong way, with the open side of the seal facing the sea, fully exposing the spring and bare steel to the salt water. On the other hand, the seawater pressure would always be a little higher than any pressure inside the bearing, so from that point of view it was the right way. I will verify with JP3 tomorrow.
Talking of JP3, Pascal got back to me on why there are 2 seals above the bearing and only one below. Normally JP3 recommend just one seal each side the bearing, but Hallberg-Rassy specially requested a design with 2 seals above the bearing. Again, we debate why on earth this would be. Then we realise.
Hallberg-Rassy are more concerned with water coming into the boat than water coming into the bearing. Which makes sense from a safety point of view. You can buy a new bearing that has been flooded, but if the boat sinks at the same time it would be a tad more expensive. So essentially they are ensuring a double barrier to the risk of flooding.
But we still cannot understand why the lower seal design allows water in behind the main bearing housing. There is a large but skinny O-ring to stop it coming all the way into the boat, but that O-ring had failed on ours with the result of severe corrosion pitting in the aluminum of the housing.
So bad in fact, that I am considering if I should get a new bearing housing. Or, I could just fill the holes with epoxy, or even Lanocote, and make some other arrangements to stop water getting back in there. Decisions, decisions. I have a few days to think about it and to hear back from JP3 on a few ideas I have.
In the meantime, there is painting to do to the top of the rudder and around where the rudder enters the boat.
But let’s get to the actual activities.
My first job of the day is to clean up in the bilge where the steering system is. It is quite a mess left in there after I removed the bearing yesterday. Once cleaned up, I’m actually happy to see that the fibre glass bowl which the bearing housing sits in, is still like new.
Then it’s outside, along with all the parts of the bearing, for cleaning. First, I remove the 3 old seals. The bottom seal which was highly corroded comes out easily. But the top 2, still in good condition are, as usual, a bitch to get out without damaging the aluminum they are placed in.
With old seals and O-rings in the bin, it’s time for my least favorite job – bath time for the bearing babies… in diesel. The grease within the pieces is jet black and sticky, like tarmac on a hot day. But after 3 lots of clean diesel they all scrub up wonderfully. That is the pleasing part about diesel cleaning: the before and after difference.
Now that all components are thoroughly degreased, it’s time to tackle some corroded parts.
Inside the bearing there are none. The bearing cap needs the O-ring seal filing out, and then it’s onto the problem-child: the bearing housing.
The spots of white corrosion turn out to be more like caverns! One is at least 10mm deep once I dig out all the compacted white aluminum oxide dust. These are clearly galvanic corrosion holes, not due to just simple exposure to seawater. Maybe the aluminum of this housing was reacting with the stainless steel of the rudder stock. Either way, I’m going to have to address it.
Someone gave a very interesting possibility with a comment on Hallberg-Rassy Club Facebook page. He said the bear metal of the rudder stock should not be right next to antifoul paint that has a copper element. There should be a gap. And also various ways to neutralize any electrical activity. Some people are really very helpful on these chat groups. Others, on the other hand, clearly need to see a shrink!
And that was my day… A pretty boring read today, I imagine. Tomorrow I will get a barrier coat onto the bits of the rudder that are normally impossible to get to.
Then get on with something else for a change. The boom? Finish locking the prop shaft into the Aquadrive now that my expensive tin of Molycote grease has arrived? Finish riveting the mast now that I have rivets again? The possibilities are endless. One thing for sure, there will be no time to get bored.
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