Sigma 33 rudder bearings - help!

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MGI

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Hi!

I had both rudder bearings replaced about one year ago. I have not been sailing a lot as the little one arrived in my family and plans had to be adjusted. This year when I spent couple weekends on a water I realised that the tiller become more and more difficult to turn and is now generating a very unpleasant (very unpleasant and loud) squeaking noise. It looks like there is a huge friction on the upper bearing. I am sure that all was working fine some time ago. What could be a reason for this? Is the only way of diagnosing the issue removal of the rudder which means lifting yacht from the water? Should a bit of grease help or the bearing is wrong size / material?

Thanks
Michal
 
It might be caused by water absortion by the bearing material (esp. bottom bearing & nylon). If it is, then replacement or reaming out are the only cures.

I had this problem on both of the Dehler 34s I had, and I was able to ease them temporarily by squirting lots of WD40 directly into the bearing and swinging the helm to full lock each way for about 5 minutes.

The Dutch Dehler Owners Club recommend a yearly dose of olive oil to keep things moving, but I think it's preventive measure rather than a cure.
 
If the bearing was made of the wrong material water absorption (rain? ) may have caused it to swell. If it's only the top bearing you may be able to drop the rudder enough to ream it out using a flap wheel on an electric drill. You would have to find a way of supporting the rudder possibly by using a rope under the rudder and going from one winch to the other via a couple of blocks attached to the toerails. Hopefully the rudder would be fairly buoyant. That's what I would try before a lift out.
 
Spyro said:
. Hopefully the rudder would be fairly buoyant. That's what I would try before a lift out.
Click to expand...

No, it will shoot staight to the bottom, guess how I know?
(Sigmas have a proper solid stainless steel stock and frame).
 
Last edited:
Quandary said:
No, it will shoot staight to the bottom, guess how I know?
(Sigmas have a proper solid stainless steel stock and frame).
Click to expand...

So you didn't have a rope undrneath it?:rolleyes::rolleyes::rolleyes:

That must have been one of those "Oh know what have I done moments".
 
Spyro said:
So you didn't have a rope undrneath it?:rolleyes::rolleyes::rolleyes:

That must have been one of those "Oh know what have I done moments".
Click to expand...

On the contrary, when the tide went down it was sitting on the sand and I did not have to dig a hole in the concrete yard. Steering back to our berth without a rudder was tricky and involved two ribs. Needed the marina travel hoist to put it back when the work was done though. (the diver in our crew would not attempt to put it back the same way)
Sigma 33 rudders tend to leak at the top and mine used to have to be drained so it needed to come out anyway.
 
water absorption as others have said. All polymer/plastic bearings absorb moisture to differing extents, but once they are tight then they also suffer thermal expansion from friction. They don't conduct heat too well either.

Dry running properties are obtained from fairly advanced lubricants built into the structure, or giving enough clearance to have some other lubricant present. The measurement and understanding of clearance is critical.

As an example we give thermal and moisture allowances detaioled below the chart here http://www.h4marine.com/Downloads/Maritex AQUARIUS General Calculator REV 20090222.xls

If you are going to do an ocean passage get it sorted properly but for day sailing you could bodge it with some crude reaming if you can get to the bearing.
 
The most practical material to make the bearings in is Delrin. Dead easy to work with and doesnt significantly absorb water. So that takes care of the upper and lower bearing. What happened our sigma was that with time an upper shim which sits on the top bearing, which takes the weight of the whole rudder and shaft, had worn down allowing the bronze tiller clamp to foul and rest on the bronze assembly thats at the top of the transom. If you know what I mean! you could see where they had been grinding and touching.Therefore the whole rudder had lowered itself by about 1mm.with wear.So when we moved the tiller, there was a loud squeeking grinding noise. This shim had worn by approx 1mm. We replaced this shim by two new delrin shims which were slightly thicker and bingo! This then raised the bronze block so that it didnt interfere with the lower bronze block on the top of the transom.No noise and lovely and smooth. We had a few made of different thickness to cover our options and have some left over so if it is this problem give me a shout as I have spares ,no charge.Nik
 
rudder bearings

mine is currently in the yard and I have noted a washer/spacer at the bottom of the shaft in between the rudder and the bottom bearing I have none on the top. The bronze casting has been wearing against the top bearing and there is a wear ring of about 0.5mm into the bronze. The sigma 33 handbook (look at www.sigma33.com for a download) doesn't show either spacer/wear ring.. If you can tell me the size and where you got them I would appreciate it.

cheers
ken
 
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