Repairing worn rudder stock

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dedwards

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We’ve discovered that our rudder stock is worn on one side by 2 to 3mm (its otherwise 60mm diameter solid aluminium) for the 3 inches where it’s been in contact with the lower rudder bearing. The boatyard have quoted to make a new one requiring breaking apart the rudder blade and a price tag the wrong side of 6k. I am wondering if there are any plausible cheaper alternatives.
For example, would it work to weld over it a new aluminium pipe with aluminium epoxy used to fill the worn area in between? We need a new bearing anyway so the extra diameter shouldn’t be an issue.
 
A specialist engineering shop might be able to repair it as you say, by welding in some material and grinding down to size.

Perhaps fill with a metal epoxy that is compatible. Make up a tubular jig to slide on and grind down to size accurately?

What about a collar such as a speedy sleeve?

6k sounds like a lot. Would a new rudder be cheaper? Might the yard sub contract the rebuild and add 100%+ for their mark up?

I had the waterfilled rudder on my last boat rebuilt by a local GRP lad for a few hundred. But no welding involved there.

You will likely save £s by doing some leg work by finding and talking to specialists yourself.

Where are you based? Forumites may well point you towards local engineering shops who could help?
 
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Thanks all for the comments so far. I’m in Gosport and have attached a pic. That quote is to scratch build a whole new rudder, which feels excessive. I’ve talked to one other machine shop who also seem keen to make new (and have offered to also split and remake the rudder blade).

Your thoughts seem similar to mine that metal epoxy to build up and then adding a sleeve to protect and offer a uniform surface is a viable option then?
 

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As you are going to fit a new bearing anyway, another thing you might do is to make the new bearing twice as long as the original so that an unworn length of the rudder stock is used.

But if you do decide to fit a sleeve, here's a link to a manufacturer:

SKF
 
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I agree that it’s not good to mix stainless and aluminium. They may seize,corrode etc. Also the SKF sleeves are too delicate I think.
If you can fit an oversized bearing (plain probably in acetal) into the tube then an aluminium sleeve epoxied into position on the stock may be an option.
 
I had an American boat ( Pearson) that used aluminium spade rudder shafts, prone to and known for premature wear and failure .
I made a new rudder and fabricated a new stainless steel 50mm shaft and web, had those welded professionally and then set them into the new rudder clam shell.
But, it’s work, a lot of hours!
And this is where the yards get you with their high £/per hour and that’s not just for the specialist..
I would suggest planning a winter project, removing the rudder and cutting out one side of a cheek to expose the shaft and tangs( web) with a grinder. Probably worth a separate thread or google..as it s a knack making the right cuts with minimal destruction.. And then take the aluminium assembly to a metal shop and have them rebuild it in stainless? Or work on the alloy as per their advice/ recommendation?

I think you will get far better value this route and a long term added reliability.
For this summer? Shove a new bearing in and life with it?

For what it’s worth, Pearson used push in Delrin bearings which were inexpensive but crude. I expect you have a stub rudder shaft and some sort of o ring seal inside the boat. And maybe a clunking or dripping rudder seal..
Good luck, there are some great machinists out there but it is always cheaper to take the assembly to them or pay the yard to just drop the rudder and
deliver it for you to your chosen engineer for re engineering the shaft. They are amazingly heavy awkward things to wrestle!
 
Try the Jefa rudder website, If your boat is an AWB, they may have a pattern for it
They may also make a complete new one for you. I had a new one when my old Polish manufactured one failed
Jefa
Although I see that you have a skeg, which becomes non standard. I would imagine that they still make skeg hung rudders. However, their bearings may help
 
Yeah them skf sleeves look a nogo due to being stainless. I did try emailing Jefa but didn’t get a response. It’d be great to hear if anybody in the uk has any experience dealing with them.

I guess where I’m going with this is: am I missing any important reason why an alu tube as a sleeve (with metal epoxy to fill gaps) is a bad idea? Am thinking a 5mm thickness tube bringing the overall diameter up from 60mm to 70. I understand it’ll require a bigger bearing but that’s shot and I need a new one anyway.
 
dedwards said:
Yeah them skf sleeves look a nogo due to being stainless. I did try emailing Jefa but didn’t get a response. It’d be great to hear if anybody in the uk has any experience dealing with them.

I guess where I’m going with this is: am I missing any important reason why an alu tube as a sleeve (with metal epoxy to fill gaps) is a bad idea? Am thinking a 5mm thickness tube bringing the overall diameter up from 60mm to 70. I understand it’ll require a bigger bearing but that’s shot and I need a new one anyway.
Click to expand...
I had a lot of help from them both emails and on the phone as I recall about a year or so before COVID
 
I dealt with them when i lost my rudder in Inverness on my round UK ( via Cally canal) trip. I spoke to a chap who said that they had a slot for my rudder in 3 weeks time (or 10 weeks)but had to place order next day. Please do not try to contact him again as he was up to his neck in work. Just pay the bill on line.. I tried to pay 5 times Internet acess in the inverness marina was rubbish & Jefra's website was playing up. I got a phone call from the wife saying that barclaycard wanted to speak to me. It seemed i had paid £3K 5 times into jefra's account. Barclays said I would have to get on to jefra & claim it back. I said why could they not just cancel 4 of the payments. What did they do- They cancelled all 5 & i missed the slot.
By now I am having an apoleptic fit as I cannot contact the Jefra guy as internet is bad as is phone line from inverness.
Eventually i got him 3 days later & he apologised. He took payment over the phone. He had saved the slot. Sent me the bearings by return so Calla marina could fit them in advance & did not charge delivery by way of apology
He explained how he was under pressure due to staff being ill & holidays etc but i got my rudder sent straight to Calla marine who copper coated it & fitted it very quickly
Everybody else I have spoken to say that they are excellent & I just caught them at a bad moment.
 
dedwards said:
Yeah them skf sleeves look a nogo due to being stainless. I did try emailing Jefa but didn’t get a response. It’d be great to hear if anybody in the uk has any experience dealing with them.

I guess where I’m going with this is: am I missing any important reason why an alu tube as a sleeve (with metal epoxy to fill gaps) is a bad idea? Am thinking a 5mm thickness tube bringing the overall diameter up from 60mm to 70. I understand it’ll require a bigger bearing but that’s shot and I need a new one anyway.
Click to expand...
Sleeving will work, why not?

Make sure the bigger OD for the 70mm ID bearings you are committing to will fit into the existing housing(s) or that those housings/shoulders etc can be modified to suit without excessive undue work in situ in the hull?
 
Sorry to resurrect old thread but I have a similar issue. Due to galvanic action, either from marina or incompatible ant-foul, the rudder stock immediately adjacent to the top of the rudder has pouting up to 5mm deep but only in parts of the circumference. Given the stock is 88mm solid aluminium what impact will that have on strength. I was thinking of (getting someone qualified) add some material and machine it down. Alternatives are to do nothing or get new rudder made (not by Jefa - I may not live that long)
I will attempt to resize photo to post
 
Is this by any chance a Jeanneau? I have seen very similar pitting on one of theirs. Oddly, an identical boat berthed next to it was undamaged. Possibly electrolytic? Check with a meter with power attached, engine on, etc. Look for any strange wire or hose contacts. See the corroded pintles case on this page Electrolytic corrosion

I think it will not have a significant effect on strength immediately but pits can initiate fatigue cracks. Keep an eye on it for now.
 
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