Way back in 2009, I cut the old rudders out of the boat and had a new set of stainless rudders fabricated. I spec’d the new ones to use delrin bushings to isolate the stainless from the aluminum, since dissimilar metal corrosion can be a problem and aluminum loses out to just about everything. In retrospect, I probably should have just used plain steel with a grease fitting, similar to the original design, because plain steel and aluminum are far more compatible than aluminum and stainless. The biggest problem with the original design was having a bronze gland nut threaded onto the aluminum shaft log, through which the steel ran. As I explained in the previous article, the whole shebang turned into unimetal during years of no maintenance.
Fast forward to 2013, and I had to remove the rudders when we were installing the new shafts and strut barrels. That was when I realized that the fabricator (who I’ve long since fired from the refit) decided to use HDPE instead of delrin for the bushings. HDPE, being a somewhat softer material, didn’t quite bond with the epoxy barrier coat, and there was a breach in the coating. That started a bit of aluminum oxide growth, which put a bit of a squeeze on the bushing. When I tried to reinstall the rudders after doing the final shaft installation (as well as the propellers) one of the rudders just wouldn’t go in without gouging into the relatively soft HDPE, pushing a mound of the material in front of the rudder shaft and bringing it to a halt.
Sooooo, I drove out the “new” bushings and ordered up a set of new-new ones, this time relying on Glide Bearings. The installation was the same, bedding the bushings in Devoe Coatings epoxy, which seemed to stick to the Glide material as well as it does to aluminum.
It really didn’t take much oxide between the log and bushing to squeeze the HDPE to the point that the shaft wouldn’t go back into place.
Flue brushes work well to clean the inside of aluminum pipe that’s used for all of the shaft logs and thru-hulls on these boats. They use a standard fitting that you can attach to extensions that fit in a 1/2″ drill chuck. The syringe next to the hole in the pic above is for applying the Alumiprep and Alodine solutions.
The epoxy that remained on the exterior is very well adhered to the aluminum, so I’m leaving it in place. I scuffed it with an abrasive pad when I applied Alumiprep and Alodine to the log, so it’s ready for coating.
Glide machined grooves for o-rings that will, in theory, serve two purposes: 1) keep the epoxy from dripping out the bottom when I installed them and 2) should the epoxy seal fail, the o-rings may keep water out of the space between the bushing and the log tube. The Glide material is much, much harder than the HDPE bushings were.
It wasn’t until I saw these pix on the computer that I realized how heavy I’d laid it on. No problem, though. That ring of epoxy near the top should help ensure the hose seals!
I applied anti-sieze to the threads so the packing will be easy to adjust when the time comes.
Next up in our 1969 Chris Craft Roamer 46 Refit: Rudder Alignment