Livin' the Dream...rudder repairs in exotic locations

Not My Real Name

Not Actually Me
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Hmmm. I'm guessing you're evading my questions because you don't know/trust me. Or, you are one of those chaps with a diametrically opposed skillset to mine, and can't/won't answer.....? If it helps, I'm hopeless at at least half of the things you do well. Probably more. I do know how to fix boats in third-world countries though, and I concede that you do other, different, worthwhile things too. If we all knew the same shit life would be interminably dull.

Completely understand your reluctance to doubt a builder that has a rep like HR. On the other hand, I have worked under other 'high rep' builders, so know how the shit goes down. If the drawing you posted is the full extent of the info HR supplied, I am both saddened and unsurprised. Boatbuilders are funny fuckers.

Hope you get both short and long term solutions, nonetheless.
The new seals were slid down from the top.

 

Not My Real Name

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As I posted before the main point is that it's already failed and apparently failed a while ago. your oil feed pipe is supposed to be a drain not an oil feed. When the drain starts dripping you note the failure, plug the drain and repair the lower seal promptly at the next haul-out. The top seal you have leaking now is supposed to be the temporary backup seal.

These get bodged up to try and overcome the hassle of the repair. The lower seal leak isn't fixed and inevitably the shaft corrodes. It's a classic situation where you get small amounts of trapped de-oxygenated salt water that leads to some very fast pitting. I'd guess that's why the lower seal doesn't seal. 

The Oil-feed is totally useless if the lower seal doesn't seal. Grease might keep you running for a while but the shaft could have some nasty stress risers from crevice corrosion.
I guess I'm confused, because I'm not totally sold that 1) the bottom seal is failed and 2) the top seal is completely failed and can't be stopped short term with replacing grease rather than oil.

The seals were replaced about three weeks ago, so "failed a while ago" confuses me.

 
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Fah Kiew Tu

Curmudgeon, First Rank
9,853
3,120
Tasmania, Australia
I guess I'm confused, because I'm not totally sold that 1) the bottom seal is failed and 2) the top seal is completely failed and can't be stopped short term with replacing grease rather than oil.

The seals were replaced about three weeks ago, so "failed a while ago" confuses me.
BJ, you may know your boat, but you need to realise that if you want to argue with Mike about this, you're arguing/disputing the opinion of a professional mechanical engineer who spent his working life specialising in ship systems and has designed many shaft/hull penetrations. I don't actually know what you did for a living but I'm pretty sure it didn't involve actually designing, building or being responsible for the construction of complex mechanical systems that had to work in a salt water environment.

Attached is a picture of the new rudder for his boat that he designed & we built in my workshop. That's 250kg with a 75mm solid shaft.

As for the 'failed a while ago' bit, it's obvious to me. Bottom seal starts failing, lets water into cavity, shaft starts corroding (most likely) eventually the top seal fails which is when you notice the problem. Before the failure of the top seal there's no real visible sign of a problem in the making.

Replace seals, new leak within days. Most likely reason, new bottom seal immediately chews out due to pitted/worn shaft area letting water in which bypasses the top seal due to wear, incorrect installation/whatever, leading to the leak you see. It's possible the seals were poorly installed given they had to be done from the top into a cavity that didn't lend itself to inspection, but that's not how I'd be betting.

If you don't think the bottom seal has failed, where is that water coming from? I thought you'd ruled out condensation from inside the hull. Easy way to find out is to pull the top seal retaining ring while the boat is in the water and see what happens. If the bottom seal is fine, you won't have a leak. But do you feel lucky?

FKT

rudder.jpg

 

Not My Real Name

Not Actually Me
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BJ, you may know your boat, but you need to realise that if you want to argue with Mike about this, you're arguing/disputing the opinion of a professional mechanical engineer who spent his working life specialising in ship systems and has designed many shaft/hull penetrations. I don't actually know what you did for a living but I'm pretty sure it didn't involve actually designing, building or being responsible for the construction of complex mechanical systems that had to work in a salt water environment.

Attached is a picture of the new rudder for his boat that he designed & we built in my workshop. That's 250kg with a 75mm solid shaft.

As for the 'failed a while ago' bit, it's obvious to me. Bottom seal starts failing, lets water into cavity, shaft starts corroding (most likely) eventually the top seal fails which is when you notice the problem. Before the failure of the top seal there's no real visible sign of a problem in the making.

Replace seals, new leak within days. Most likely reason, new bottom seal immediately chews out due to pitted/worn shaft area letting water in which bypasses the top seal due to wear, incorrect installation/whatever, leading to the leak you see. It's possible the seals were poorly installed given they had to be done from the top into a cavity that didn't lend itself to inspection, but that's not how I'd be betting.

If you don't think the bottom seal has failed, where is that water coming from? I thought you'd ruled out condensation from inside the hull. Easy way to find out is to pull the top seal retaining ring while the boat is in the water and see what happens. If the bottom seal is fine, you won't have a leak. But do you feel lucky?

FKT

View attachment 313438
I'm not arguing. I'm trying to understand what the fuck he's talking about.

Do the words "I don't understand" and "I am confused" sound like I'm fucking arguing?

 
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Not My Real Name

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As for the 'failed a while ago' bit, it's obvious to me. Bottom seal starts failing, lets water into cavity, shaft starts corroding (most likely) eventually the top seal fails which is when you notice the problem. Before the failure of the top seal there's no real visible sign of a problem in the making.

Replace seals, new leak within days. Most likely reason, new bottom seal immediately chews out due to pitted/worn shaft area letting water in which bypasses the top seal due to wear, incorrect installation/whatever, leading to the leak you see. It's possible the seals were poorly installed given they had to be done from the top into a cavity that didn't lend itself to inspection, but that's not how I'd be betting.
I have no idea who Mike is or what he does for a living - he could be a mortician or a professional bagpipe player for all I know about the guy.

----------------

There is OIL coming out of the top of the thing, and there is no obvious water except that one little bolus.

This is what is confusing me - if the bottom seal was leaking, wouldn't there be salt water coming in? A fair amount of it? And not just oil oozing out?

I've not ruled out condensation. Some mornings in this cold water literally drips off the window frame over my head. If you run your hand along it you get a shower from condensation.

I didn't say it was "ruled out" because I can't prove that. I said it "didn't seem likely", as most of the condensation is more on the cabin trunk and around the lewmar windows. We do get some in the out of sight places in the boat like this when it's cold and nasty like it's been the last couple of weeks.

We're talking one bolus of water, about the size of your fingernail. If more shows up, I'll let you know.

I am just trying to understand what he is saying, what you are saying, and how - like in your example above - when you a draw a conclusion based on what you inferred, not what I actually said, it relates to the reality of what I am seeing.

There's a reason I paid someone to do this job in the first place instead of doing it myself, I know my knowledge limits and what my comfort zone is in dealing with things, and this is outside it.

 
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vibroman

Super Anarchist
Something like this, suggested by the contractor, could keep a slight positive flow of grease in there.

https://www.skf.com/ph/products/lubrication-solutions/lubrication-systems/single-point-automatic-lubricators/gas-driven-single-point-automatic-lubricators/index.html

You can dial it out to dispense a small amount of grease periodically for up to 12 months. Disposable, it seems.
BJ Iwould not go there. There are several variants of that and nearly all are uncontrollable. Push too much when hot not enough when cold. There is an electric version that is controllable. They are all designed to push grease through a bearing so unless you have a purge port you will blow seals. Sounds weird but you need to determine is the water ingress is condensation or not. Taste will let you know that.

If salty I suspect the premature failure is due to shat damage. In that pic there was what appeared to be damage at the seal area. If that was not meticulously cleaned with scotchbrite (not emery cloth as it removes too much material) theres a fair chance the new seal will leask. I vote to pack with a nice thick high consistency grease (NLGI 4 or greater). Remember a typical grease gun put out 1500 psi plus and lip seals withstand 15 psi or so. If you could hand pack it it would be preferable.

good luck 

 

Not My Real Name

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Did the guys who did the job report on the condition of the shaft at the lower seal?
They said they cleaned it up carefully and it looked pretty good.

Beyond that? I don't think they took pictures.

That picture I posted is from 11 years ago, before the rudder was cleaned up and put back in.

 

MikeJohns

Member
478
123
Hobart
There is OIL coming out of the top of the thing, and there is no obvious water except that one little bolus.

This is what is confusing me - if the bottom seal was leaking, wouldn't there be salt water coming in? A fair amount of it? And not just oil oozing out?..................................
Not when the oil head is greater than the water head. It’ll just keep weeping oil as the oil has a higher pressure but lower density so it’s fed in under a greater head and rises to the top and weeps out of the now apparently failed upper seal.

What happens when you disconnect what is now the oil feed pipe.  That port should be a free draining hole that drains small amounts of water ingress and indicates a failed lower bearing with a more constant flow.
That will tell you everything you need to know. If you get a dribble of seawater  then the lower seal is failing or has failed. If you don’t then there’s no problem with the lower seal. Don't worry about sinking the boat it's easily controlled.


 I was looking at the initial picture you posted and the lower shaft seal bearing area looks corroded on the shaft but it’s hard to tell so I'm just surmising. Who added the oil feed and why ? It really serves no useful purpose unless its an attempt to fix a lower leaking seal. Putting an oil feed into the drain hole is not great practice  because it leads to a small amount of water sealed from the atmosphere by the oil. The shaft whether alloy or stainless needs oxygen to protect the metal surface.

Below is a pic of  the general arrangement.  note the location of the drain that your setup is forcing oil into. 

l_hr45 hr46 version 1.jpg

 

Not My Real Name

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Not when the oil head is greater than the water head. It’ll just keep weeping oil as the oil has a higher pressure but lower density so it’s fed in under a greater head and rises to the top and weeps out of the now apparently failed upper seal.

What happens when you disconnect what is now the oil feed pipe.  That port should be a free draining hole that drains small amounts of water ingress and indicates a failed lower bearing with a more constant flow.

THANKS - that's that I was trying to make sense of.

That will tell you everything you need to know. If you get a dribble of seawater  then the lower seal is failing or has failed. If you don’t then there’s no problem with the lower seal. Don't worry about sinking the boat it's easily controlled.

 I was looking at the initial picture you posted and the lower shaft seal bearing area looks corroded on the shaft but it’s hard to tell so I'm just surmising. Who added the oil feed and why ? It really serves no useful purpose unless its an attempt to fix a lower leaking seal. Putting an oil feed into the drain hole is not great practice  because it leads to a small amount of water sealed from the atmosphere by the oil. The shaft whether alloy or stainless needs oxygen to protect the metal surface.

There was no corrosion evident on the shaft that I saw, but I didn't do the work. The contractors that did the work were pretty conscientious about showing me what they were doing and what they found. If they saw something like that, they would have raise a red flag. Their mandate was to "have a look an see if it's worse than just failed seals, otherwise replace the seals," not just "here are some seals, put them in."  Meaning that dropping the rudder and doing more work was on the table if they found something, so they were supposed to be looking.

Below is a pic of  the general arrangement.  note the location of the drain that your setup is forcing oil into. 

View attachment 313443
I believe the oil drain and the tank is original to the boat. At least it was there when I bought the boat in 2006 (it's a 1997), though I'm the third owner. The guy I bought it from made some dodgy decisions with maintenance so I wouldn't put it past him.

Tomorrow I'll plan to pull the hose off and see what comes out. If it's salt water, then I'll make arrangements to haul the boat and sort it. If it's not, I'll pack it in grease. Gently.

 

TQA

Super Anarchist
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35
Caribbean
Off the wall thought.

Could you turn it into a conventional stuffing box gland with some gland packing string. Then add a remote greaser. ?

 

ice9a

Member
412
8
Do you know where the loaded (with cruising load) waterline is relative to the top lip seal?

My last boat had a lip seal on rudder shaft which was fine for multiple 100k miles, but the seal was 15cm above the water line, so it was really there just to stop splashing - could totally fail and the boat would not sink.

I wonder how difficult it would be to put a boot on this, clamped to the outside of that bearing housing, running up as high as possible (to just below the quadrant or autopilot tiller arm), ideally with some sort of light seal up there, but really not necessary (if it is high enough).  Put a little drain into the boot if no top seal, and just drain it before passages.

You would think such a boot would require taking the top bearing (and quadrants, etc) apart to slide down, and that would be best . . . . but it will be under no pressure and I suspect it would not be hard to do even without disassembling anything - glue, heat weld, or bolt clamp a vertical seam in the boot, perhaps even a double wrap on the boot with a wide strip of velcro on the outer wrap would do the job (for a year or two).   Something along these lines would not be too hard to do (without haul-out) and would contain any leak (and the resulting potential oil mess) and would give me peace of mind.

On the bigger issue of rudder design for cruising, with little relevance to your situation - got to say I personally loved having an absolutely bulletproof spade with bearing above the waterline - we banged that rudder hard into rocks a couple of times and it was not going to break (we did once bend a small section of the tip and once a very small deflection in the shaft), and it was super easy to drop when we needed to (I did it a couple of times single handed just sitting in a slip) and I installed a new one in chile (with better spade shape) sitting in a slip.

 
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Bugsy

Super Anarchist
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Canada
I know I am late to this party, and I am certainly no expert, but on your list of options (some posts above) I think one of your options may be "do nothing".  That is, monitor the oil consumption rate, continue to inspect, gather information, etc.  

That is, continue to collect data until you are confident of making the best decision with the best information. 

Fair winds and thanks for all your useful contributions.  I now know something about HR rudders that I didn't know before.  

 

Zonker

Super Anarchist
9,268
5,196
Canada
our oil feed pipe is supposed to be a drain not an oil feed.
I think it is more likely to put a positive head on the oil in there to resist the hydrostatic pressure of seawater.

It's very common practice for seals like this on ships.

 

Zonker

Super Anarchist
9,268
5,196
Canada
Corrosion on the shaft causing slow leakage? Sure, quite possible.

Installed upside down? Possible but sounds like your guys were pretty careful so if they know what they were doing, less likely

Damaged during installation? Quite possible too - bigger shaft seals like that take a bit of pressure to get them in place and if there is any burr to do a bit of minor damage

Catastrophic failure is unlikely but slow increase in leakage is possible. Monitor the oil level in the tank daily until you get an idea of rate of leakage.

 

Not My Real Name

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our oil feed pipe is supposed to be a drain not an oil feed.
I think it is more likely to put a positive head on the oil in there to resist the hydrostatic pressure of seawater.

It's very common practice for seals like this on ships.
That's the way it was explained to me by the guys that did the work. The feed tank puts a small amount of positive pressure inside the seals to keep water out.

 

randii

Member
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Sacramento area
I like the subject of the thread... living the dream, indeed. This isn't the best part of cruising, but keep your sense of humor and willingness to learn. This will make a helluva story to relate in the future.

Randii (got nothing to share on shaft seals... all my rudders are transom-hung)

 

Not My Real Name

Not Actually Me
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2,767
I like the subject of the thread... living the dream, indeed. This isn't the best part of cruising, but keep your sense of humor and willingness to learn. This will make a helluva story to relate in the future.

Randii (got nothing to share on shaft seals... all my rudders are transom-hung)
There's a certain...paradise mythology...that surrounds the lifestyle and keeps vloggers in Patreon subscribers.

The reality is that's it IS worth doing, but sometimes you run into a string of shit despite your best intentions.

 
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