Tides Marine Rudder Bearing on Freedom 40/40

[geoffschultz]

During our trip through the Great Lakes I could feel a thump when the boat was rolled. It felt like it was coming from the rudder, but you can only imagine all of the possibilities that ran through my head. When we had the boat pulled, the first thing that I did was to figure out what was causing the thump. I found that the outer chase of the lower rudder bearing wasn't in contact with the rudder tube. There was less than 1/16" all around the bearing as shown in the photo below.

The outer chase of the bearing rotates when the rudder is turned. If I insert something between the chase and the tube to keep it from rotating, the inner part of the bearing (I don't know what the correct term for this is) rotates smoothly, so I believe that the bearing is in OK condition. These are Tides Marine bearings (http://tidesmarine.com/rudder-bearings.html) and are machined out of a single piece of UHMW-PE, have no metal, and are designed to last for a "lifetime." The lower bearing is press-fit into the rudder tube and the 2.5" carbon fiber rudder stock is epoxied to inner part of the lower bearing.

The entire rudder hangs on an upper bearing, which is made of the same material. The carbon fiber rudder stock is though-bolted at the top, so it should be next to impossible for it to drop. Based upon old photos that I have of the rudder assembly, it appears that the rudder hasn't dropped and that it has simply come loose from the from the tube. After discussing this with Dave Balfour, who ran the group who commissioned the boat for Freedom, we both feel that's the correct answer. Ideally I'd drop the rudder and install a new bearing, but that opens up a can of worms due to having to grind the epoxy off of the rudder stock, etc, and the feeling that it would be of limited value.

So, the suggestion at this point is to insert some material between the out race and the rudder tube to keep it from moving. It has been suggested that I don't want to epoxy the outer race into place in case I need to replace it. At this point I have 2 suggestions and am looking for comments and/or more suggestions.

1) Inject a material such as warmed up 4200 using a syringe into the surrounding space.
2) Epoxy coat some very thin Popsicle sticks and epoxy them into place.

Any additional comments and/or suggestions would be more than welcome. I'm flying back to Milwaukee on Tuesday to implement this and do some other work before the boat gets shipped to CA.

-- Geoff

 

[kloudie1]

Wow.. not a fun one, Geoff.. OK here are my thoughts.. The bearing-to-post load is mostly compression and not torsional.. Your idea to put something in the gap is a good one .. Whatever you put in there should be as long (top to bottom) as the bearing so that the compression load is impressed on as much bearing as possible... It looks like the bearing Inner diameter has been eaten away slightly by the rudderstock?? OK.. My suggestion would be to push the rudder all the way over and measure the gap. (measure in several places because the wear may not be symmetrical fore/aft and port/stbd) Find a material in half that gap dimension that is in or can be cut into thin strips that can be driven into the gap to fill the gap. Drive in strips about 1" wide or less, opposite each other until the gap is filled and centered. If you can find some flat nylon sheet, it would be a fine material to use since it will swell slightly as it absorbs water. This swelling should lock the nylon to the post and the bearing to the nylon. If ya can’t find nylon, you could use a poly material and thinly coat it with a foaming polyurethane glue (like Gorilla Glue) . I would not use wood.
Interesting problem.. Let us know what you do, Geoff..

 

[geoffschultz]

Claude,

Thanks for the suggestions. I had been trying to think of an expanding adhesive, but hadn't considered Gorilla Glue as I hadn't realized that it was waterproof. I also like the idea of using thin nylon sheet which will expand, as that would provide a mechanical bond to the UHMW-polyethylene, which is very difficult to glue.

Oh, regarding your comment that the inner diameter had been eaten away by the rudder stock. I don't believe that to be true at all.

-- Geoff

 

[geoffschultz]

I'm happy to report that the rudder bearing has been stabilized. After looking at the bearing I could see that there was virtually no play in it, and that's after 40,000 miles on the boat. The only play was about .060" side to side in the tube and virtually nothing front to back. The nylon sheet that I had was .060" and I sanded that using a belt sander into 1" wedges about .030" at the thickest part and going down to a thin edge at the narrowest. I slid these into the sides where it was widest.

I decided to glue the entire bearing as I was worried that when the bearing was side loaded that it might pull away from the rudder tube, so I used a horse syringe with a 2" long #14 needle to inject glue into widest spot. I then used the rudder to turn the out chase and distribute the glue. I repeated this until I had coated the entire outer chase and then I re-inserted the nylon wedges.

Gorilla Glue expands about 4x, so I spent a while collecting glue that was forced out of the gap. After about 2 hours I checked and the bearing was locked in place and there was no side to side movement. Hopefully this will be a long term solution.

Thanks for your suggestions!

-- Geoff