rudder stop problem - Beneteau 393

[spaman]

after mostly problem-free last season, noticed uneven rudder range once out on the hard for annual wash and antifoul. remains unresolved despite now afloat, but going nowhere.
no damage/impact noticed (or admitted to) during haul out.
full range to port, but only 2/3rds to starboard (as evidenced by autohelm rudder angle indicator).
the chain at the wheel/binnacle appears perfectly aligned on the cog. dead central when rudder straight, correct range when turning to port, but blocked when 2/3rds to starboard (ie I don't believe the chain is the problem).
the stops at the rudder post have been adjusted to allow for maximum range, yet it is still not right.
five people (so far) have ventured into the aft locker for a look-see, but all have come out without an answer.
I feel this problem should be easy to fix. the Beneteau steering arrangements cannot be that complicated...
despite that, I cannot sail the boat in this condition.
help???

[Terra Nova]

Originally Posted by spaman

...five people (so far) have ventured into the aft locker for a look-see, but all have come out without an answer...

Five "people"? Hire a pro to diagnose this.

[GeoPowers]

Are you sure it isn't an issue with the rudder angle indicator? I don't see how 5 people could look at it and not verify the rudder is clear of any obstructions and seems to be swinging as designed.

[spaman]

thanks - the indicator is reading accurately. the problem was evident when the boat was on the stand.
person #6 (expert ?) looking at it today or tomorrow.

[Boracay]

Possibly (Assuming cog/chain/cable steering) :-
1) If the cable is held by clamps these have become loose and the cable has slipped.
2) The chain has jumped one or more sprockets on the cog.
3) The rudder stops have moved.
4) The quadrant has moved relative to the shaft - key has sheared?
5) The key holding the cog on the shaft has sheared.
6) The tangs in the rudder itself have sheared.

Has a yard worker worked on that section of the boat?
How old is the boat?
Has the boat been used regularly in strong winds?
Has the steering been "serviced"?

[delmarrey]

Most rudder shafts have a quadrant, or tiller arm for hydraulics, and threw the quadrant/tiller there is usually a pin that passes through the center. This pin may have sheared and is allowing slippage in one direction.

If yours has this quadrant, then mark the shaft and the quadrant while it is against the good lock, and then turn it all the way to the other lock. Then check your marks to see if they are still aligned.