Well, there is progress to report. My latest photos have been added at Flickr:
Joujou Dufour 32's photosets on Flickr
Continuing the tale, after 6 days of soaking in distilled vinegar, we pulled the Shaw plug, placed a piece of hard wood against the bearing, struck it repeatedly with a heavy ball-peen hammer, with no movement of the bearing.
Next we assembled a one foot piece of iron pipe with a short PVC sleeve that fit closely in the hole of the bearing; struck the pipe repeatedly with the hammer, hoping the leverage would be adequate to break the bearing free. Again, no luck.
Out of frustration at this point, I started thinking about destroying the bearing with a reciprocating saw and chisels. BUT I’d risk damaging the aluminum housing.
Called Loughborough Marine Interests, LLC, in Newport, RI, the sole USA distributor of JP3 bearings, and spoke with David. He was very helpful. Found out that the cause of the lockup is calcified algae; he knows of 3 other sailboats currently with the same problem. David explained that JP3 bearing tolerances are too close, allowing the smallest foreign materials to restrict the rudder shaft and movement of the bearing. For 5 years he’s been recommending to the JP3 folks in France that they adjust the tolerances, but they have been unresponsive. David suggested continuing on the chemical route, to avoid damaging the housing. I also ordered a new 60 mm bearing, just in case, though the order can not go in until the French return from their August vacations.
David advised that the bearing is made of a neutral nylon, called “Ertalyte”, which is extremely stable. Full detail is at:
Ertalyte® PET-P & Ertalyte® TX
My friends and I could find no chemical that would attack calcium while being inert to aluminum except for distilled vinegar, which is diluted acetic acid.
A Coast Guard friend suggested shrinking the nylon bearing a bit by placing dry ice inside the opening to chill it, thinking the calcium bond should then be easier to break. We tried it. A 20 minute first attempt produced hairline movement. A 40 minute second chilling, while we had lunch, did the trick. Though still needing the iron pipe and hammer, we could move the bearing fore & aft and starboard to port. We continued to bathe the bearing in vinegar, cleaning surfaces as they were exposed. (See the relevant photos on Flickr.)
At the end the day, we left Joujou with the Shaw plug back in, and the rudder tube filled with distilled vinegar.
Next steps: Return, and continue moving the bearing, and cleaning with vinegar. We need to reach a point where we can flip the bearing 90º so that we can drop it out. After that, more cleaning, and assessing the condition of the bearing and housing.