Rudder bearings. good or bad

Juniperskip

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This is another of the "how long is a piece of string" questions, or so I have just discovered. We had some lateral movement in the rudder, that we had professionally checked before heading off for a years trip. Advice was that all was fine so we left it, monitored the amounts when diving and then on return checked again on lift out. True to the advice no increase to the movement (I should say it is minimal) but I decided to have the bearing changed. I was surprised that there was no bearing race in this modern design just a solid sleeve at the top and bottom of the stock. Clearly the lower one was slightly out of tolerance on build so the the fix was to have a new one made and we are now solid as a rock.
It did surprise me that my vision of what the bearing would look like and reality were miles apart - the drawings supplied were not helpful. So I would start at looking at the style of bearing and move the questions on from there!

Doesn't quite answer your questions but thought the scenario might help some...
 

pugwash60

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Speaking from ignorance here but I'd have thought that the type of rudder set up would be fairly important to know, i.e. is it hung on the back of a long keel, on a skeg or just a modern blade hanging under the boat like a dinghy's rudder. I'd have thought that in the first two scenarios then a little play wouldn't be all that significant but in the third one it would be 'unhelpful' verging on unacceptable.
 

vyv_cox

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My Sadler has a skeg mounted rudder with bearings at top and bottom. There was noticeable play, maybe 1 mm, in the top bearing when I bought the boat. It didn't seem to be a serious problem so I left it to see if it worsened. 15 years later it is almost exactly the same.
 

BobE

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Rudder Bearings Good or Bad

Vyv,
My Sadler 32 is on the hard and I'm trying to check the "deck level" rudder stock bearing where there's a little fore/aft play..( one sideways)
The two rudder/skeg bearings seem fine although if I take the ground the tiller lifts about 5 mm (lift keel 32)
Have you any idea what's under the teak cover to the bearing??
What's it made of etc...?
Cheers Bob E...
 
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Check any steering connections first. If I wobble my rudder, it feels as if there is play in the top bearing, but a more detailed look reveals that it is the rod end on the steering gear.
 
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vyv_cox

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Vyv,
My Sadler 32 is on the hard and I'm trying to check the "deck level" rudder stock bearing where there's a little fore/aft play..( one sideways)
The two rudder/skeg bearings seem fine although if I take the ground the tiller lifts about 5 mm (lift keel 32)
Have you any idea what's under the teak cover to the bearing??
What's it made of etc...?
Cheers Bob E...

Sorry, no I don't. I have never found it necessary to remove the cover. My rudder also lifts, probably more than your 5 mm. I suggest you ask on the Sadler and Starlight forum http://mly.gamalanhost.net/forum.asp where I know there are owners who have replaced the bearing.

Vyv
 

Neil_Y

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Strictly speaking any bearing has a designed running clearance range at new and in most cases an advised clearance when it is considered ready for replacement.
This calculator is for Maritex, other materials should also have design spec's. You enter in the shaft OD and the carrier ID to get the clearances (these are broken down into running, thermal, and moisture allowances)
http://www.h4marine.com/Downloads/Maritex AQUARIUS General Calculator REV 20100519.xls
for 60.00mm shaft 80.00mm carrier
0.22mm running clearance change when clearances gets close to 1.50mm
 
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BobE

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Thanks for the replies...
The Tiller to stock interface is fine ... no athwartships movement at all ...
There is just enough fore and aft movement in the top (Deck level) bearing to annoy one when helming but as said before, no sideways play at all...
I'll have a look at the gamalan forum again... maybe I missed it but couldnt find anything about the very top bearing...
Thanks again for replies ... Much appreciated
Cheers Bob E...
 
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