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Perhaps I do need a surveyor and a lawyer.

The sleeve through the boat has not changed, so there is no way to misalign the rudder. There are no bearings on a Catalina 42, just a fiberglass sleeve that the rudder post slides into. If the rudder was not built symmetrically I guess you could consider it misaligned, but that would be Catalina's fault.
With all due respect, this sounds very strange.
Firstly, rudder bearings at small GRP boats is there not only to make movements smooth but also to take the load from the rudder. GRP in itself is actually rather soft, will not work as a bearing - no way. A simple form of rudder bearing is a bush bearing, often made of Delrin (also found in blocks and such) or today even better materials (Delrin bearings usually lasted ~ 10 years).
Usually in boats of this size there are two bearings, a lower and an upper, often about 3 ft apart. This is to handle the forces in two places, and to avoid too high torque in one point - again, GRP is not good at handling high stress.
These bearings are sometimes somewhat difficult to see without actually removing the rudder. When I had some issues with my rudder it took me some time before I really understood how it was designed and attached. I have had it down some few times, to get things really right.
I have seen your other comment about bearings, I guess you then refer to usual roller or ball bearings.

Secondly, when fitting a rudder shaft into sleeve / bearings / call-it-whatever it is essential that the measurements are very accurate, accuracy less than 0.1 mm. A new rudder, with a new rudder shaft is likely to need new bearings (sleeve or whatever). Without changing bearings, there will be too much play and the rudder will move to one or several unbalanced positions.
It may be so that you cannot detect any play in the rudder, which is possible while still having some play:
a) the rudder may be misaligned so the shaft is under some tension. Then one doesn't feel the play even if it is there.
b) somehow I got the impression you also have a steering wheel. That mechanism adds some extra friction which may shadow the play in the rudder.

What you have to do is to haul the boat, release the steering mechanism so the rudder is free of any attachment. Then you should be able to detect any form of play and misalignments.
Most likely you have to remove the rudder (think before doing this, it use to involve some work), and measure very carefully all diameters. check where the bearings are, and swap to new bearings (if you insist that there are no bearings, then you in any case have to build up new material on which the rudder rests - if GRP or epoxy is used you are likely to have repeat this very regularly).

I myself do not trust any yard to do work like this. Very often they do a fast job, do not have the time to consider design and construction, no time for exact measurements and no time at all to await to get new bearings made.

If you want to know more about rudders and rudder bearings then I recommend the Jefa homepage, probably Jefa rudder and steering systems.

/J
 
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