Rudder Bearing Replacement

by Bill & Judy Stellin  Jaywalker April 2007

I have hull #6 which used a Harken bearing as the lower rudder bearing.  It failed within 2 or 3 years of the boat being built and it wasn’t until this year that I was in a place where the work could be done by someone I trusted.

Even so, it was a harrowing experience since the yard, (Monty North, Barcelona Spain) decided to use a bearing made by Jefa Marine of Denmark.  This meant it wasn’t just a replacement, but rather, a complete rebuild of the whole system.  Jefa is one of the industry’s largest bearing builders and as it turns out, J-Boats uses their bearings in current production boats.

Monty North’s engineer  specified a bearing using lip seals instead of the packing our boat was built with.  I was never keen on packing, as it often had to be adjusted to keep water out of the boat. This change required extensive glass rebuilding as the new bearing is completely different from the one J-Boats installed.

Monty North ultimately did a superb job but only after two tries.  On the first try, they put a man on the job for rebuilding the structure holding the bearing, which had no supervision and frankly didn’t know what he was doing. Jefa has a wonderful web site that gives all the information necessary for a proper installation.  Trouble was, the engineer never looked at the instructions, didn’t specify the proper material or lamination technique and never supervised the workman. 

The pictures that follow show the progress and results of both jobs.  The first attempt had to be done completely over again, as the bearing was never laminated into the hull correctly and leaked between the hull and bearing outside surface. Plus it had no secondary water ingress protection nor enough lamination strength.  To their credit, Monty North did the job over again after I insisted they follow the procedure outlined by Jefa. The second time, they did everything Jefa suggests and at no cost to me.  It did, however take one week; on top of the 8 days the first job took. The steering is now better than ever and I highly recommend Jefa’s self-aligning bearings with integral lip seals which does away with bothersome packing glands.  As a secondary protection against water ingress, an aluminum tube is bonded to the bearing with a rubber gaiter on top sealing the tube to the rudderpost.

Old Harken bearing frozen solid to the rudder post.  It acted as a giant bushing. Note the smooth surface which was turning in its housing.  The corroded part is the end exposed to the water.

Original bearing housing being cut out.

Housing removed and upside down.  Bearing turned in housing acting as a giant bushing.

New bearing being improperly installed and without alum tube.  Green seals are lip seals.

Notice how low the glassing is on the bearing.  Also the man used polyester resin instead of epoxy as called for.  The leaking occurred between the glass and the bearing surface.  All of this had to be ultimately cut out back to the original hull.

This was the final product after the first disastrous attempt. The lip seals are only slightly above the water line with no second line of defense in case they failed.  None of this was called for or recommended by Jefa.  Where the white gel coat meets the black bearing surface water was coming in while motoring.

Cutting the new bearing out for a second try at doing it right.

Working from outside before chipping away all the lamination from the inside.

Temporary rudder. This bearing makes on heck of big hole in the boat when it is out.

Most of the first attempt glass cut and chipped away.

This is a pile of the glass that had to be chipped away from the first lamination attempt.

The hull from outside underneath and reduced to its original thickness.(about 2 inches)

Bearing with alum. tube bonded to it.  Assembly is about 14 inches high.

Tube and bearing being bonded with epoxy resin in hole.  Note thickness of tube.

Bearing, tube glassed in with epoxy resin and wooden supports ready for glassing in.

Rudder back in place, rubber gaiter clamped to rudder post and ready for clamping to glass surface after gel coating.  This gaiter prevents water that might get past the lip seal from getting into the boat.  It is very elastic and quite large allowing the rudder to move to its stops with no noticeable resistance on the wheel.

Final product, gel coated and before gaiter is clamped to glass surface.

Everything is back where it belongs and ready for sailing.

The helm is now feather light in any conditions and there is a noticeable reduction is power needed by the pilot. I think there is a saving of 1-2 amps because of less resistance.

Bernie, I don’t know if this job has wide appeal due to the fact J-Boats changed the bearing soon after our boat was built.  But even if you have a better bearing than the original Harken, the work might be interesting.  Who knows even the more modern bearings that could be 8-9 years old may have to be replaced.  These photos can give one an idea of what is in store for them. 

One last thought.  It is a good thing I took extensive photos which I showed to the yard alongside Jefa’s instructions.  There was no question what was and wasn’t done.  As they say, “a picture is worth a thousand words”.

Regards

Bill Stellin    s/v Jaywalker    J/42,  Hull #6, built 1996