Catalina Rudder Bearing Replacement

While anchored two seasons ago, I noticed a clunk when Priorities rocked back and forth from the wakes of passing boats. The sound clearly came from the rudderpost area in the lazarette. After visually observing the rudderpost wobbling back and forth with each clunk, I figured last winter was finally time to act on a project I had been putting off for a while: replacing the top rudder bearing.

Priorities is a 1996 Catalina 400 Mark I, and like many Catalinas around her size and vintage she has rudder bearings made from a hard plastic. They are a wear item, but should last a decade or two. One symptom of excessive wear is a bunch of play in the rudder that’s noticeable when shaking the bottom of the rudder after haulout. Rudder bearing wear is a gradual process, and isn’t a crisis when first noticed. However, I can see where it might aggravate wear on steering cables and autopilot drive linkages… also items on my winter project list. It also wasn’t going to get better with time, either.

Several years ago, I hired a professional to help me replace the bottom rudder bearing. Though the job itself wasn’t that complicated, it needed to be done while the boat was out of the water and high enough above the ground to allow us to completely remove the rudder from the boat. With a rudderpost that extends 3 feet above the rudder, we needed 3 feet of clearance under the bottom of the rudder in order to remove it. I worked with the boatyard to do the project while still in the slings after haulout, but before being placed on her cradle. An alternative is to dig a hole in the ground below the rudder… but that’s not that easy in frozen Wisconsin, or for those of us that store on concrete!

I had purchased the complete set of rudder bearings from Catalina Direct when I replaced the lower bearing. It was a whopping $620! Though I initially planned on replacing the top bearing the same year I replaced the bottom, the looseness seemed much better after replacing just the bottom bearing. I put off what I saw as unnecessary work until I started hearing that clunk two seasons ago.

After haulout last winter, a quick check revealed nearly an inch of play when shaking the bottom of the rudder. The bottom bearing itself had become loose from the hull, too, which was part of the problem. It did seem, however, that most of the motion was in the top of the rudderpost, confirming my observations earlier in the season. After our steering cable failure on our trip to Pentwater that same season, a steering overhaul was big on my list of winter projects… so I replaced the top rudder bearing this same winter.

I started this project by climbing into the bottom of the lazarette and getting photos of everything. Having photos of how systems look when fully assembled helps when reassembling them later… especially if i don’t finish until spring.

Since I planned a complete steering overhaul including cable replacement, I disconnected the steering cables from the quadrant, and removed the quadrant from the rudderpost. I also removed the autopilot tiller. When I replaced the lower bearing a few years ago, I delivered the boat to the boatyard a day before haulout before disconnecting the quadrant. Some other 400 owners have used their emergency tiller for the final maneuvers to the crane… but mine didn’t fit until recently.

Since I didn’t need to replace the lower bearing this time, I didn’t need to completely remove the rudder. Therefore, I did this project out of the water in the cradle, making logistics simpler.

Before any more disassembly, I compared the new top bearing with the old top bearing. The new top bearing is a self aligning bearing, involving a partial sphere sandwiched between two plastic rings. The self aligning feature allows the bearing to “wiggle” to stay aligned while not allowing lateral movement. Apparently it helps reduce friction when underway, when the rudderpost bends with stress. Unfortunately, its overall size is larger than the original on my boat.

With some careful measurements and fussing, I figured that simply mounting the top bearing on top of the bearing box wouldn’t work due to a lack of space. Some other Catalina 400 owners, especially owners of later models, might not have this issue since I’m willing to bet each boat’s bearing box is semi custom made and has slightly different dimensions. Some boats might even use this new self aligning bearing as an OEM part.

I came up with a design that should be pretty strong: the upper bearing straddles the bottom of the bearing box, transferring any lateral loads directly into the box. The bottom flange of the bearing mounts under the box, held up by a piece of G10 fiberglass and through bolts that also hold the top flange in place. To keep the spacing right, the top flange had a ¼” piece of G10 under it as well. I used ¼” G10 under the bottom flange, but in retrospect the bottom G10 piece probably should have been ⅜” or ½” for additional stiffness.

On my boat, the packing components around the rudderpost looked like they needed attention… large amounts of caulk had been put around a joint earlier in its life. Since a new packing assembly came with the bearing assembly, I decided I would replace it, too. This meant I needed to lower the rudder a foot to give me enough clearance above the rudderpost in the lazarette to swap old with new. Lowering the rudder this amount would also give me room to make minor modifications to the bearing box to accommodate my plan.

Filled with foam, I’ve heard the rudder isn’t that heavy when in water. On the hard, however, it’s pretty heavy, and felt like it weighed 100 pounds. It’s held up by one bolt above the top bearing. Since I was working alone, I built a stand of scrap 4×4 lumber to prop up the rudder a fraction of an inch and removed the top bolt.

After triple checking my measurements, I lowered the rudder down about a foot. I widened the hole in the existing bearing box to allow the upper bearing’s lower flange to fit better, and drilled holes for the through bolts. I installed the lower section of the packing assembly with screws, sealing the edges with 4200. Then I loosely fit all the remaining components that would end up under the bearing box around the rudderpost: the rest of the new packing assembly, the lower flange’s G10 brace, and the lower flange of the upper bearing. Then, I raised the rudder to full height again.

Getting the through bolts to line up took some work… I ended up drilling out the holes in the G10 pieces one size larger and used washers. The rudder is held up by a new stainless ring (supplied with the rudder bearings) atop the upper bearing. This ring needed to be drilled out as well to fit the new 5/16” bolt that matched the existing hole in the rudderpost.

Now that the new top bearing assembly fit correctly, I felt I could reinstall the loose bottom bearing again with adhesive. The bottom bearing is not self aligning, so I waited to glue this in place until after the top bearing was installed. Lowering the rudder one last time a few inches (or all the way out if replacing the whole thing), I removed the screws holding the bottom bearing in place, and pried the bearing out of the rudder tube with a crowbar and sharp knife.

The bottom bearing is mostly held in place with 3M 5200. Some call this the “devil’s glue,” since it forms a permanent bond that’s awful to remove from most substrates. However, the bearing is plastic, and not much bonds to plastic very well. On both occasions when I’ve removed the bottom bearing it wasn’t a disaster, especially since I could use a knife to cut through the bond. To facilitate future replacement, I used 5200 only on the bottom flange, NONE on the sides that go 2 ¼” into the rudder tube.

There are screws that hold the bottom bearing in place, too. With a hull thickness of 1 to 2 inches in this area, I used 1 ¼” long screws since the bearing flange is ½” thick. When I first replaced the bottom bearing I was told these screws are mostly there to hold the bearing in place while the 5200 sets. As a result, I didn’t tighten them much. At haulout last fall I noticed they had sheared off, possibly contributing to it coming loose again. This time around, I tightened the screws more firmly.

Raising the rudder one last time while the 5200 cured to ensure it cured in alignment, I installed the retainer ring and screw at the top bearing. A few days later I wiggled the rudder back and forth to check for any binding of the bearings. Without any steering connections, the rudder moved very easily, with only a slight resistance in one direction.

New ½” flax packing was installed in the new packing assembly, and the top compression ring tightened moderately to prevent leaks. This packing is above the waterline, so the boat won’t sink at the dock if this fails, but a seal is needed in waves and maybe when motoring.

To complete the project I reinstalled the quadrant and autopilot tiller. The bearing box cover was reinstalled and resealed with silicone caulk, and the emergency tiller access port got a new O-ring purchased from McMaster-Carr.

After a season of use, including several instances of being stressed when sailing overpowered, and sailing in 6-8 foot waves, everything seems to be holding up well. Hopefully, the new bearings will last many more years. If or when they need replacement again, though, it should be easier… assuming the bearing design doesn’t change again!