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steele

J boats JP3 bearing info

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I just went through a long and expensive repair and thought I would share my experience. This is not a rant against a particular product, but it might save some boat owners some grief.

My late model French built 109 developed a very stiff helm under load over the last season. After the usual suspects were ruled out I had it put on the hard and pulled the rudder. The problem was failure of the lower bearing housing. It is aluminum, and holds a dougnut shaped bushing that is self aligning. The housing had corroded and swelled, no longer alllowing the bushing to align under load, such as going hard up wind. It was so bad the bushing, which should be removable by hand, could not be budged with hammer and had to be cut out. The fix was to replace the whole lower assembly with a non aluminum one by Jeffa. The result as a huge improvement, even better than prior to my noticing the problem.

This is not a unique issue, the yard I was in had 3 boats with the same issue, not all Js. The bearing housing can not be painted since it has a bushing inside it that moves. It is buried in the hull with no way to attach an anode. They are known to fail quickly if cooper bottom paint is used on or close to the housing, similar to an aluminum saildrive. In my case there was no evidence of bottom paint on the housing, but some advise no antifoul anywhere near the rudder and bushing. I am not sure what you are supposed to do about marine growth in the area which could impede movement of the rudder.

What to do? If you have a French built J boat, or any recent European boat (Dufour owners take note), try to figure out the manufacture of the bearing system. The next time the boat is on the hard drop the rudder and take close look the bushing and housing. Keep any non compatable bottom paint way away, and budget for a replacement in future. Mine was 7 years old.

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This is (unfortunately) a very common problem. Aluminum just does not last in this application. I have replaced Harken, JP3, Custom built, whatever, if there is aluminum it is going to fail. PYI & the all plastic Jefa bearings are your best replacements if they will fit.

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Yes, the more I researched this, the more failures came to light. Jefa ended up running an extra production cycle this summer to meet the demand. I was lucky the outside diameter was a close match to the original housing. Lucky, as in just a few boat bucks as opposed to major boat surgery, and missing 6 weeks of the summer sailing season. It seems this is a doomed to fail component. Why J, and other boat companies, are using unprotected aluminum below the water is a mystery. 

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Copper oxide antifoul destroys any aluminum that is wet 

to upgrade the lower bearing use a non metallic one 

jefa makes one , jp3 might make one 

contact J- boats 

its not an easy job to replace the bearing ...cut the old bearing  out with a hole saw ..then epoxy laminate in a new bearing assembly 

be careful with alignment 

https://jefa.dk/products/roller-bearings/6bb/

 

 

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