Hints and Tips



Rudder Bearing Replacement JOD35

At the end of the 2002 season the rudder stock had seized to the lower bearing making the boat totally unusable. Looking back through paperwork that came with the boat it would appear that there had been problems with the rudder in the past.


My initial point of contact was with Sea Ventures as they were the main Jeanneau agents in the UK, this revealed that the replacement bearings were expensive, but there was much information available re the removal of the bearing especially with the rudder still attached.


The process outlined below together with the photos supplied should give you an idea of the work that was involved.


The rudderstock was firmly attached to the lower bearing small movements could be made using the tiller but it was impossible to move the rudder blade so a frame was shaped and clamped to the blade so I could move the blade with out climbing into the boat to use the tiller.


The initial plan was to try to remove the aluminium around the bottom of the delrin ball allowing the ball to be lowered out with the rudderstock. It was important not to damage the rudder or the boat.


After removal of a large amount of aluminium using drills, file and hacksaw blades it became clear that I was unlikely to be able to remove the ball as a whole still attached to the stock.

I made the decision to destroy the ball hoping that this would allow me to free what remained from the stock. After drilling and chipping it away with a wood chisel the delrin ball split, this allowed me to open up the split and free the stock, this was lowered out of the boat. A time of much celebration as it had taken many weekends to get this far.

My next problem was to remove the aluminium housing for both the bottom and the top bearing as both were held in place with copious quantities of silicone and large screw rings. This involved a few more weekends making special spanners and citing away bits of mastic and fibreglass.

With the aluminium housings removed the holes that remained were in good condition.

While all this work had been going on research over the Internet had revealed a possible alternative bearing to the original. Jefa Bearings in Denmark were contacted, they were very helpful and emails and drawings passed back and forth eventually settling on a set of their self-aligning roller bearings.


The Bearings were ordered along with the waterproofing tube and collars that were to fit onto the rudderstock. There is a photo showing the old and new.

As can be seen the new lower bearing had a parallel outer case, the original being conical in shape. The outside diameter of the new bearing was slightly smaller that the exit hole in the hull but as the original bearing was conical the hole in the hull was tapered; this was cut to a parallel hole using a large hole saw. The required for the top bearing was larger than the existing, a tapered plug was made to fit in the original hole allowing a larger hole saw to be used to cut the correct diameter hole.

The new Jefa bearings were temporally fitted in place and the rudder was fitted, this allowed alignment to be checked and the measurements to be taken for the aluminium tube. A delrin collar was specially made allowing the tube to be fitted onto the bottom of the top bearing.

Permanent fitting was effected by using epoxy to hold the lower bearing in place, screwing the top bearing to the deck and after fitting the waterproofing tube the lower bearing and tube were glassed into place.

The results at this early stage seem to have been well worth the effort involved. The rudder is so free that it blows in the breeze while the boat was on its cradle. It has been afloat for three weeks now and although I haven't been sailing yet, (connecting up all the electrics etc.) I have moved the boat in the marina; the rudder is very light and responsive. First sail should be this weekend.


Charles Mitchell - JOD 35 - Hysteria