Replacing Rudder Bearings

Gypsy

Member
Joined
14 Feb 2004
Messages
584
Location
Sydney and Australian East Coast
www.tech-x.com.au
A few weeks back I asked for advice about changing the rudder bearings for a Bavaria 44 (2002). I received a few good hints and warnings as one has come to expect with the range of experience on this forum.

Yesterday I hauled out and assisted my local shipwright to do the job.

The process is simple but the very fact that the bearing was binding on the rudder shaft made the execution a little difficult. For those who may face the job here is a summary:

1) Undo quadrant clamp and set it back from the shaft.
2) Remove the key between the quadrant and the shaft
3) Loosen clamps of the rubber gator on the stern tube.
4) Place something under the rudder to support is as it exits the bearings/stern tube. It will be heavy!! 60-80kg or more.
5) Undo the top of shaft retaining/locking ring
6) Place a piece of hardwood on top of shaft and knock down with a heavy hammer. We ended up using a 7-10kg sledge hammer. Use a hardwood rod when the shaft goes below the top of the bearing.
7) If the bearing is tight, it will take time and energy to persuade the shaft down through the lower bearing.
8) On the B44 the shaft diameter at the lower bearing is 68mm but tapers after about 200mm inside the gator to 65mm where the quadrant attaches. The top bearing is 50mm.
9) Once it comes free, after 200mm, the rudder will drop like a stone. Be ready, it is heavy!
10) The lower bearing was stuck in the mount. We had to cut it out. The top bearing came out by rotating 90deg and dropping thru the slot.
11) When replacing the rudder, use 3 gorillas to lift it into place with someone in the lazarette to guide it. Quickly put the top lock ring in place.
12) When positioned vertically, tighten the ring to minimize movement. There shouldn’t be much with new bearings.
13) Re-attach the quadrant and check cable tensions.

The steering is now “as smooth as silk”. It is amazing to realise how this must have been gradually binding and adding resistance. There must be thousands of boats (not just Bavs) with this problem creeping up as I write.

I was impressed to realise that the rudder shaft is solid stainless steel!

On a final note, I decided to use a different material for the new bearings. I am not sure what material the Bavaria originals are made of. They are white, they could be Nylon or Delrin or something else. I searched the web for alternative materials as I don’t want to do this every 5-6yrs. I found a material/product called Vesconite which claims to have 0.07% size change in 100% humidity (compared to 3% for nylon). It is used in mining pump and marine bearing applications. I bought tube of appropriate raw dimensions and found a machinist to create what I needed modelled on Bavaria originals which I purchased.

I am really impressed with the smoothness and lightness of the helm. Was it this good when the boat was new? I can’t remember. The real proof of the Visconite will be in 5yrs. Watch this space.

Anyone want to buy a pair of Bavaria 44 rudder bearings, unused?
 

hairbox

Member
Joined
10 Oct 2003
Messages
300
Location
UK
Visit site
Hi Gypsy
thanks for the info I have a 40 which suffers from stiff steering how did you know it was time to change the bearings and where did you purchase the new Bavaria ones from?

regards
 

Bav34

...
Joined
7 Aug 2006
Messages
4,259
Visit site
Excellent report. Thanks. Now bookmarked.

Something that I have always wondered is how the rudder shaft is actually held in place. I can see the retaining ring that you talk about. It has two holes in it that I guess are for a special tool ?????

If this ring spins on in the same way as a nut on a bolt, why doesn't it turn when the rudder does?
 

rogerthebodger

Well-known member
Joined
3 Nov 2001
Messages
13,776
Visit site
Visconite is the only material to use for bearings below the water line.

My rudder, prop shaft and bow roller are all Visconite. I have also used a flat sheet as a ware strip between the bow roller and windlass to protect the stem fitting and deck from damage buy the anchor chain

There is a new version caller Visconite Hilub which is white in colour which is said to be better but have not used it yet.
 

cormorant

New member
Joined
19 May 2005
Messages
57
Visit site
Yes I have used Vesconite now for rudder and cutless bearings...time will tell. There do seem to good reports about this stuff.Did you order from S Africa, they don't seem to have an agent in the UK?
 

samwise

New member
Joined
6 Dec 2001
Messages
1,523
Location
Suffolk
kalessin-of-orwell.blogspot.com
If the original bearing material was nylon, no wonder it was causing problems, the material swells when immersed and would bind on the shaft. I would have thought it unlikely that Bavaria would cost cut to that extent.
However, I would also think that if you have to replace the bearings every four or five years, there is something more seriously wrong with the basic design. We changed the bearings on our Westerly before a big trip in 2006, the originals (1988 boat) were still ok, but there was sufficient play in them to justify a change on the grounds of preventive maintenance. Hopefully, if it needs to be done again in 20 years time it'll be someone else's problem!
 

Gypsy

Member
Joined
14 Feb 2004
Messages
584
Location
Sydney and Australian East Coast
www.tech-x.com.au
I say the Bavaria originals are nylon. I suggested nylon or delrin but I don't know. I do know that this problem is clearly something which is becoming more common on modern production boats but not confined to Bav. It sounds like you had the opposite problem, wear. I had no play over the 6yrs and she has sailed 12000nm.

It could be a wrong material choice. Maybe the new ones are a different material, again I don't know. However I made a choice to spend more money now on a more sophisticated material to avoid a repeat. From the good feedback by other Vesconite users I might have fluked it.
 

Gypsy

Member
Joined
14 Feb 2004
Messages
584
Location
Sydney and Australian East Coast
www.tech-x.com.au
Looking back I can realise it occurred gradually over the last 3 yrs. This year I noticed I couldn't tweak the steering by fingertip when under way, I had to use pressure. When I took the boat for a sail after sitting on the mooring for 3-4mths I quickly felt the stiffness when motoring away from the mooring, to the point that I dropped anchor to take a look for something wrapped around the rudder -but nothing found.

After making sure there were no other causes in the steering system (I have dual wheels) and researching the web on the subject I found that it was not an uncommon problem and that the lower bearing was the most likely cause as it sits in water.

I purchased the replacements from our local (Sydney) Bavaria dealer, North South Yachting. As we are so far from the factory they actually hold a reasonable range of spares.

I can't believe I put up with the way it was but this is a slow process which sneaks up on you.
 

Gypsy

Member
Joined
14 Feb 2004
Messages
584
Location
Sydney and Australian East Coast
www.tech-x.com.au
On my Bav44 the top screw-on ring is the only thing holding the rudder in position vertically. Mine has 2 holes for a tightening tool (C spanner) but it has a cut horizontally on one side which leaves a space of about 1mm which is compressed by a screw in the top of the ring to lock it from moving. The ring SHOULD move with the rudder shaft. There is a Delrin/Nylon spacer under the ring to provide a low friction surface for it to run on.

I have read of a problem on a Bav47 where the ring came off and the rudder dropped out of the top bearing and caused grief. In my case this could not happen because the quadrant works within a steel frame in the lazarette which holds various pullies for the dual wheel steering cables. If the rudder drops by more than 15mm I would get scraping noises as a warning and the rudder could drop no further.

In accidents/troubles I have read about on other (non Bav) boats they have reported that their rudder floated when broken off or when they tried to remove it whilst in the water. If that were the case there would be an upward pressure rather than down. From the weight of mine I can't imagine that there is enough bouancy to float and give upward pressure.

I have marked the position of the ring/shaft with a marker pen and it is always visible from the cockpit so I just check it now and again. I have been aware of this locking mechanism for 3yrs and checked the marks regularly, it hadn't moved.
 

Bav34

...
Joined
7 Aug 2006
Messages
4,259
Visit site
Thanks Ray. The reason that I ask is that I am considering dropping my rudder as I have just noticed that the lower bearing not only rotates on the shaft but also inside the tube i.e. you can spin it!

Not sure if this is actually a problem as there is no more play when I wiggle the bottom of the rudder than on other similar boats in the yard and there is absolutely no play when the boat is in the water. /forums/images/graemlins/confused.gif

What do you think stops the lower bearing rotating in the 'tube'? The only thing that I can think of is if the tube and bearing are tapered and perhaps the rudder has dropped slightly or the outer face of the bearing has worn, but the gap between the rudder and the hull looks ok i.e close and as I say, there is no problem when in the water.

Am I worrying about nothing?
 

Gypsy

Member
Joined
14 Feb 2004
Messages
584
Location
Sydney and Australian East Coast
www.tech-x.com.au
I believe the lower bearing holder is slightly tapered to allow for tolerances with the bearing diameter (maybe the upper one too). After 4yrs (9,000nm) sailing my rudder had a slight play, no more than 15mm at the tip. I tightened up the top ring about 1/2 a turn which cured it.

My guess is you just need to tighten up the the top ring. Tighten incrementaly, say 1/4 turn at a time and check the play and ensure it doesn't cause any binding. Is there any kind of locking screw on the top ring such as I described?

The bearing in mine was tight in the holder, we could not rotate it to allow it to come out the slot. We cut it out. There was a small amount of corrosion on the inside of the aluminium holder which would explain why the bearing was stuck and could have been part of the shaft binding problem if the pressure on the outside from the corrosion pushed inwards. I'll leave that to experts.

On a recent report about a Hanse which lost its rudder in the Irish Sea, they found that the aluminium rudder shaft had pitting near the lower edge of the bearing although this was not considered to be the cause of the failure. The point was made that whilst everyone is aware of problems with copper based anti-fouling attacking aluminium sail legs which require a tin based paint, one never hears warnings of painting copper based anti-foul near to the rudder bearing socket/shaft.

The corrosion of the bearing socket on mine was minimal but this time I made sure the top of the rudder, the bearing holder and 100mm around the shaft were painted with the tin based paint I used on the saildrive. The rudder shaft on mine is solid SS so it is not at risk, but I want to protect the bearing holder.

We learn something every day!!
 

Tranona

Well-known member
Joined
10 Nov 2007
Messages
42,736
Visit site
I have a 2001 37 that did 7 years as a charter boat with no sign of either wear or stickiness. As you say, I don't think that the original is nylon as it would cause problems very quickly. I am not sure if the stock on mine is stainless or aluminium, but the maintenance people in Corfu where I keep my boat saw stickiness is usually caused by fouling on the stock where it goes into the bottom bearing. Cured by dropping the rudder and cleaning.

I shall have a closer look at mine when it is out next spring.

Thanks for the good description of how to do it.
 

Gypsy

Member
Joined
14 Feb 2004
Messages
584
Location
Sydney and Australian East Coast
www.tech-x.com.au
If the bottom bearing is binding like mine, the rudder doesn't drop, you have to BELT it out! I can easily imagine stiffness occurring if there is a build up at the bottom of the bearing.

Of the first 5 years of life, 2 of the 4 winters were spent on the hard, and the 5th had 5 weeks out of the water whilst shipping to Sydney so that could help explain why the problem cam eup now after being in the water 2 yrs with less use.

Anyway there are plenty of variables in boating and this forum is a great way of learning what can happen and how to fix it. I have benefited on the learning curve in the past so hopefully the description I have provided and the discussion which followed will help others.
 

Bav34

...
Joined
7 Aug 2006
Messages
4,259
Visit site
[ QUOTE ]
Is there any kind of locking screw on the top ring such as I described?


[/ QUOTE ]

Will check (and tighten) next time I go down to boat. Too cold today /forums/images/graemlins/frown.gif

Thanks again.
 

EyeCandy

New member
Joined
4 Dec 2008
Messages
18
Location
Kiama, NSW, Australia
Visit site
Hi Guys,
On the strength of this subject I have just registered.
I have a 2005 Bavaria 39 in Turkey and last week I went through the same struggle to remove the rudder as Gypsie. The lower bearing was very tight on the shaft and required lots of pounding to get the rudder out. The bearing was too tight in the housing to budge with a 10 pound sledge hammer so I too drilled out the bearing. Discussing this with the Bavaria agent in Sydney we learned that the bearing material is Ertalyte. On the specs given by the Ertalyte manufacturer it seems to be a suitable choice of material for underwater bearings. Dufour amongst others use this material too so I dont believe this is the cause of tightness.
I found a thin layer of hard material(possibly corrosion products) inside the lower housing. It chipped off redily with a careful scraping action. There was a small area (10mm dia) of pitting inside the housing but not in contact with the ertalyte bearing. I believe the tightness was caused by this material squeezing the bearing onto the shaft. I have yet to figure what to do about preventing the corrosion. Any thoughts anybody?

I installed a new Bavaria supplied bearing and it fitted easily and the steering now is dream - dare I say better than new.

Bav34, if yours is the same as my 39 there is a plastic sleeve between the lower bearing and the top of the rudder (so as to keep the rudder clear of the hull). This normally is loose so dont confuse this with the lower bearing turning in the housing.

ALSO I know a New Zealand Bav 39 in Turkey that had their bearing machined out this year because of severe steering tightness. This boat is a 2006 model. I can't say about any corrosion.

Andrew
 

Bav34

...
Joined
7 Aug 2006
Messages
4,259
Visit site
Hi and welcome.

Gypsy is spot on with his description '' Mine has 2 holes for a tightening tool (C spanner) but it has a cut horizontally on one side which leaves a space of about 1mm which is compressed by a screw in the top of the ring to lock it from moving''.

It looks like all that I have to do is slacken the locking screw then turn the ring which will draw the rudder further up into the tube against the bearing.

Regarding the sleeve OR lower bearing I'll take a piccie of it tomorrow and post it here just to show what is rotating.

Perhaps you could look and advise.

Many thanks.

ps Ignore my dumb comment ''If this ring spins on in the same way as a nut on a bolt, why doesn't it turn when the rudder does? '' Of course the ring turns when the rudder does .... I get confused easily these days /forums/images/graemlins/mad.gif
 

Gypsy

Member
Joined
14 Feb 2004
Messages
584
Location
Sydney and Australian East Coast
www.tech-x.com.au
Hi Andrew, welcome to the forum. Its always good to have new input.
I saw your blog thru a link from the NSY newsletter and read about your rudder problem. Tried to reply via the blog but it is for short messages only. Anyway, you have found the solution.
The lower bearing in mine was also stuck in the holder and we had to cut it out. After scraping out a small amount of corrosion and sanding the area where the bearing sits, the new bearing fitted in nicely and could move as it should.
I think you have a point about the external buildup of "crud" and/or corrosion causing the compression of the bearing onto the shaft. But how to stop it in the future?
Our boat was hauled out for 3 of 6 winters so that would reduce the build up if crud but most boats around Aus and NZ stay in the water all year. As mentioned earlier, I am now ensuring that there is no copper based anti-foul near the bearing holder to avoid any corrosive influence.
I have used Vesconite as an experiment, keep an eye on the forum to see if my experiment is a success. On the other hand, it is not a good test as I have changed 2 things (bearing material and anti-foul) so how will I know which is the solution if all goes well?
 

Gypsy

Member
Joined
14 Feb 2004
Messages
584
Location
Sydney and Australian East Coast
www.tech-x.com.au
As the weight of the rudder and the quadrant is on the top ring you might find it difficult to turn. If the boat is out of the water, try to find a way to support/lift the rudder when you try to adjust the ring. It will also show you how much vertical adjustment is needed/possible.
I couldn't find a suitable 'c' spanner but a small chain grip pipe wrench works a treat. The chain goes around the outside of the ring and a handle gives leverage and an angle to cause the chain to grip.
However, after considering your problem of play, I'm no longer confident the adjustment will help. Although I read that the bearing holders of this type are slightly tapered you would need something at the top of the rudder to push the bearing up into the taper in order for it to succeed, but as you/we know, there is a washer/spacer between the rudder and the bearing holder which would limit the vertical movement of the rudder and not allow any upward pressure on the bearing to cause it to seat better.
Anyway, take a look. You learn something new every day.
 

EyeCandy

New member
Joined
4 Dec 2008
Messages
18
Location
Kiama, NSW, Australia
Visit site
Ray,
I gather that your boat was also in the Med. You don't suppose that the increased salinity and temperatures there are a factor in this? My boat has also been stored out of the water each year since new in 2005.

I have read another forum suggesting that we should bond the aluminium housing to a zinc anode to prevent corrosion of the aluminium. What do you think? It seems to work for the saildrive. The nearest metal object is the Stainless steel rudder shaft but I can confirm that these are isolated from each other and the boats DC earth (the engine block). But something is causing the housing to corrode. Have a look at http://www.c-2.com/forums/pviewall.tpl?fno=499.5&uid=F&SKU=2008211042545.56

Andrew
 
Top