Repairing worn rudder stock

[Tranona]

Most likely cause on the Bavaria is antifouling with copper based paint right up to the bearing housing. Current recommendation is to leave a 10cm ring around the housing and use Trilux for that. Alternatively Coppercoat the hull as I did with my second Bavaria.

 

[eddystone]

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.

No Bavaria
Is there a treatment that can inhibit fatigue cracks eg filling in and matching to profile?

 

[eddystone]

Most likely cause on the Bavaria is antifouling with copper based paint right up to the bearing housing. Current recommendation is to leave a 10cm ring around the housing and use Trilux for that. Alternatively Coppercoat the hull as I did with my second Bavaria.

Yes I have Jefa datasheet on that

 

[Tranona]

Are you replacing the lower bearing with the roller type? As Vyv says doubt the strength has been compromised unduly so you might consider using an epoxy filler like this sylmasta.com/product/superfast-aluminium-stick-113g/ to fill and fair. I have not used this specific product but used similar many years ago on the aluminium front cover of a Yanmar 1GM. it was still sound after 10 years when I sold it.

 

[vyv_cox]

No Bavaria
Is there a treatment that can inhibit fatigue cracks eg filling in and matching to profile?

Almost any treatment cannot overcome the increase in stress concentration. Filling with epoxy is merely cosmetic, the pits are still there unchanged. Even weld repair is a stress concentrator. Rounding out the pits will in theory reduce the stress concentration but would need to be done very carefully.

 

[eddystone]

Are you replacing the lower bearing with the roller type? As Vyv says doubt the strength has been compromised unduly so you might consider using an epoxy filler like this sylmasta.com/product/superfast-aluminium-stick-113g/ to fill and fair. I have not used this specific product but used similar many years ago on the aluminium front cover of a Yanmar 1GM. it was still sound after 10 years when I sold it.

The drawings of the roller type bearings supplied by Jefa would not fit in the existing housing - the dimensions are very different. The existing is like a slightly flattened sphere of white acetal type material.

 

[bitbaltic]

Why not approach Jefa for a replacement? I had one delivered this winter 5 weeks after commission.

It replaced a rudder which had been rebuilt 10 years earlier with a new stock after severe pitting to the original- pitting is very hard to repair with epoxy. In the case of my boat’s original rudder stock, the epoxy filling had deteriorated and caused the bearings to seize.

My boat is a Hanse 301 and problems with the original rudders are very well known though. Increasingly these boats now have Jefa replacements.

I and others have found Jefa’s replacement prices competitive with boatyard rebuild quotes.