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S&S Swan Maintenance - Grinding top rudder bearing on Swan 431? Pls. advise
11 January 2021 - 17:14
Join Date: 12 January 2011
Posts: 11

Grinding top rudder bearing on Swan 431? Pls. advise


Our rudderstock is held by two metal plates. It looks like the upper part of our rudder stock grinds something away. Is this metal from those plates? Or, delrin, or bearings?

What could be happening here?

The rudder stock can also be moved a little on the top site and you can see it moving from site to site, very little, maybe 1mm. You can feel the movement also by hand.

The rest of the rudder stock does not seem to move as far as we can see. Where the rudder goes out of the ship it looks all good.

We have red all posts on the forum about rudders we could find, but could not find an answer to our situation. We would love to know how to solve this.

We have seen this at first a year ago after an Atlantic crossing. Now after a sailing trip of 7 days, we see new grinded material. We had the steering wheel locked for 8 months between these periods. Laying at a mooring, the rudder had minimum influences from movements of water waves. 

We hope somebody can give us advice.

Is a haulout required? It looks like the upper plates can be taken off, without removing the rudder, is this so? Do we need to replace the bearings? Take the rudder off?

We are in Antigua, with good repair facilities available.


We added some pictures

Thank you in advance

Martin and Henny

Snow 431#3

Top part and grinding result

Middle part and grinding result

Lower part where all looks good

11 January 2021 - 18:53
Join Date: 02 January 2008
Posts: 1547

Dear Martin and Henny

Pls check if the rudder stock turns in the black plastic bearing. If not, the plastic bearing has frozen to the stock, and forces the aluminium ring outside the bearing to turn against the aluminium housing.
It appears that by opening the horizontal bolts holding the assembly it can be lifted up and removed from the stock, but the frozen bearing may now hold it firmly. CRC or similar could be tried.
Kind regards

12 January 2021 - 14:24
Join Date: 12 January 2011
Posts: 11

Hi Lars,

Thank you very much for your explanation. We consider it good news. It looks indead frozen like you explain.

We wish we had asked the question earlier so possible damage would be less.

If we understand you correctly, the outer ring/tube should be firmly connected to the aluminium plates. The rudder stock should move within the black ring.

We will trie to get the plate off and loosen up the frozen ring on the rudder stock.

You mention CRC. Do you mean Lithium grease? I used that before, trying to grease (an already frozen plastic bearing)

If this all works, do you think we should also fill the fractional mm space that is grinded away between the metal tube and the plates? Maybe have new plates made, maybe ask Nautor to make them? Or try to fill up the litte space with something?

Thanks again for your insight. We will update the results.

Martin and Henny

12 January 2021 - 17:36
Join Date: 02 January 2008
Posts: 1547

Martin and Henny

It is likely that the plastic has swollen with the time, by moisture or oil absorbtion, some plastics have such undesirable long term properties.
Afraid that the plastic ring can sit very tightly, a propeller puller type tool could be tried to force the assembly to move up along the stock.
Pls read about CRC here
Check if there is a local metal shop able to make a replica, or, if the damage is minor, repair it with hard epoxy. The plastic ring is better replaced with one made of POM (Delrin) plastic 
Kind regards

12 January 2021 - 19:36
Join Date: 12 January 2011
Posts: 11

Hi Lars,

We tried to remove it in different ways but there is just no movement. We will try to get hold CRC, we now have only wd40. Maybe if it sits a night it can work its way in.

We will look for a propellor removal tool, we will need it anyway some day.

At least we now understand whats happening here. To be continued.

Thanks again. Your advice is very helpfull. 

Martin and Henny

19 March 2021 - 18:32
Join Date: 12 January 2011
Posts: 11

Just an update, problem solved.

We have had Antigua Rigging remove the frozen bearing and they had a new bearing made. Excellent service, they know the problem and have been doing this before as they are very familiar with Swans and worked with Nautor a lot. They wre also very well know with Nautor spare parts who referred them too.

We are very pleased with their knowledge and expertise.

Now the rudder bearing can go on for the next 25 years.

Thanks to Lars and Stan from Antigua Rigging again.

Martin and Henny

New parts aluminum and Delrin


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