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Old 24-09-2019, 17:06   #16
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Re: Rudder check

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A set of bearings from Catalina is close to $1,000.
Machined to specification from a variety of plastics here in Mexico is about $200, with 2 day turn around.
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Old 24-09-2019, 17:06   #17
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Re: Rudder check

We have had the same issue with corrosion in this area of the rudder post (you can barely see it in this photo, but it is the only one I can find).

Originally, our rudder post had the same nylon bearing, but we have recently replaced both the upper and lower bearings inside to allow stable and non-binding movement without the need for the plastic ring. As you know, stainless steel is only 'stainless' in the presence of oxygen; when starved of oxygen, rust forms (corrosion occurs). As others have mentioned in regards to adequate water flowing past this area, we believe the plastic bearing prevented adequate exposure to the necessary oxygen.

Admittedly, we also messed up on several occasions by allowing the copper-laden bottom paint to reach this part of the rudder post - again, interfering with the needed oxygen exposure and also setting up bi-metal corrosion. Now we are super-careful to keep the antifoul off the rudder post.
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Old 24-09-2019, 17:07   #18
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Re: Rudder check

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Machined to specification from a variety of plastics here in Mexico is about $200, with 2 day turn around.
I'm on the way, plan is to be there next year. Heading to Panama from here.
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Old 24-09-2019, 17:10   #19
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Re: Rudder check

What does the washer even do? I can not see what its purpose is.
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We have had the same issue with corrosion in this area of the rudder post (you can barely see it in this photo, but it is the only one I can find).

Originally, our rudder post had the same nylon bearing, but we have recently replaced both the upper and lower bearings inside to allow stable and non-binding movement without the need for the plastic ring. As you know, stainless steel is only 'stainless' in the presence of oxygen; when starved of oxygen, rust forms (corrosion occurs). As others have mentioned in regards to adequate water flowing past this area, we believe the plastic bearing prevented adequate exposure to the necessary oxygen.

Admittedly, we also messed up on several occasions by allowing the copper-laden bottom paint to reach this part of the rudder post - again, interfering with the needed oxygen exposure and also setting up bi-metal corrosion. Now we are super-careful to keep the antifoul off the rudder post.
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Old 24-09-2019, 17:16   #20
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Re: Rudder check

The washer keeps the rudder from flying up into the hull if the boat pitches hard.

Some boats have a flanged bearing and some have a plain bearing and washer. Some have both. Ask the engineer. Seemed like a good idea at the time. ��
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Old 24-09-2019, 17:20   #21
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Re: Rudder check

Ok,I suppose the rudder could possibly move up, obvious really, thanks.
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The washer keeps the rudder from flying up into the hull if the boat pitches hard.

Some boats have a flanged bearing and some have a plain bearing and washer. Some have both. Ask the engineer. Seemed like a good idea at the time. ��
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Old 24-09-2019, 18:56   #22
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Re: Rudder check

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How many pull their rudders to have a look?

I'm on the hard in Trinidad, there was a little slop in the rudder bearings, not huge but abit. I've got quite few miles to go to get home so I thought I'd change them.

I was surprised to find quite abit of what looks like crevice corrosion on the rudder post, just above where it enters the rudder.

This area sits directly under what Catalina calls a thrust bearing, just a plastic ring that has no load on it, it just sits between the lower rudder bearing and the rudder.
Prudent of you to have checked! I pull our rudders frequently, to lubricate the shafts. On our boat its easy, the boat can be afloat.

With composite shafts, our rudders are bouyant, so I've fitted a couple of acetal thrust washers where the shaft enters the hull. Maybe your rudder is slightly bouyant, which would necessitate the thrust washer?
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Old 25-09-2019, 04:41   #23
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Re: Rudder check

Hi 44, your right. I was thinking about this last night and I believe the rudder is buoyant. Its a large rudder (2.8m) total length and theres alot of foam in it. Even with the 4 inch diameter SS shaft it would still be buoyant. When I Iifted it the other day buoyancy didn't cross my mind, its bloody heavy.

I think rudder failures may occur more than we realise.

Two boats crossing the Atlantic at similar times to me this year lost their rudders. One was a friend on an older 57 lagoon , no problem as he has two ( hes lost two over the last 10 years) he flew a rudder in to St Helena.

Also a mono lost theres , not sure of make as I dont know them, they used a drogue to get to port.
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Prudent of you to have checked! I pull our rudders frequently, to lubricate the shafts. On our boat its easy, the boat can be afloat.

With composite shafts, our rudders are bouyant, so I've fitted a couple of acetal thrust washers where the shaft enters the hull. Maybe your rudder is slightly bouyant, which would necessitate the thrust washer?
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Old 02-10-2019, 06:29   #24
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Re: Rudder check

I now have the new rudder in and are ready to splash.

I dont have a definitive answer to what caused this corrosion. The boat sat in marina for a decade plus prior to me purchasing her, maybe this has something to do with it?

I'd like to throw a couple if questions out there, I'm no genius in this area.

First of all if I had a stray current leakage wouldn't this result in faster anode deterioration? My anodes last easy a year.

Second question, the rudder shaft isnt protected by any anode, all other underwater parts are, shaft, maxprop and SS P bracket (strut). The rudder come from factory this way.

I could run a wire from the shaft inside the locker to the bolts of the SS P bracket which has two anodes on it, is this something to consider?

All thoughts welcome.

Thanks in advance.

Cheers Dale.
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Old 02-10-2019, 06:42   #25
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Re: Rudder check

Dale,

Are you sure there is no connection from your quadrant to the main grounds?

If you walk around and look, you will find some rudders with zincs. It always seemed random to me. Roxy has a ground cable from the quadrants.
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Old 02-10-2019, 06:48   #26
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Re: Rudder check

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Dale,

Are you sure there is no connection from your quadrant to the main grounds?

If you walk around and look, you will find some rudders with zincs. It always seemed random to me. Roxy has a ground cable from the quadrants.
I'm sure, and I know it's from factory this way, I've rung Catalina. They assure me this is quite normal.

Yes, I do notice a number of boats have a anode attached to the rudder.
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