DickB
regular
Reged: 20/12/2002
Posts: 495
Loc: Surrey, UK
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A friend of mine has a Bene 36cc and noticed that he could turn to port fully but not starboard. The reason was that the clamp for the autopilot arm had slipped by about 30 deg. which restricted movement one way.
Well we undid the four bolts and moved it back into the correct position, but I noticed the rudder stock is fibreglass about 3" diameter.
It is diffictul to decide how tight to make the clamp. Too tight and you run the risk of crushing the rudder stock. Too loose and it slips...
Has anyone else had a similar experience and if so how do you assess the clamp tension? 
thanks
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Dick
Less work, more sailing...
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nicky71
regular
Reged: 01/09/2006
Posts: 114
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Be careful tightening that. If you read the MCIB report into the sinking of the yacht Megawat, it was due to wear on ther rudder stock caused by a poorly fitted autopilot.
www.mcib.ie/download_stream/?id=253e696c9fc60322
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davidpbo
regular
Reged: 14/08/2005
Posts: 393
Loc: us: Macclesfield Boat: Cumbria
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Any chance of inserting something to improve the grip without increasing the clamp force ? maybe a strip of butyl rubber (used for pond lining) or a piece of anti slip cloth (probably not robust enough).
Releasable gasket compound?
Epoxy a metal sleeve around the stock and fit an enlarged clamp?
I have no experience in this area, just some suggestions as to things I might think about if the problem were mine.
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Bilgediver
regular
Reged: 06/06/2001
Posts: 1400
Loc: Scotland
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Be careful tightening that. If you read the MCIB report into the sinking of the yacht Megawat, it was due to wear on ther rudder stock caused by a poorly fitted autopilot.
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This came to mind here too and not only how the auto bracket is secured but also ensure it isn t mounted on the shaft mid span between bearings where it imparts bending moments......
Fibre glass rudder stock........are you sure??????????
How is the steering quadrant or tiller attached???
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Eastern Scotland and beyond.
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2Tizwoz
regular
Reged: 23/06/2005
Posts: 1677
Loc: Northumberland
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There is a further cause for concern in the Megawat rudder failure report in that 'Awlgrip Gold' a copper bearing anti-fouling had been used. The presence of aluminium in drive legs and that corrosion problems causes their manufacturers to prohibit the use of copper based anti-fouling is well known.
The rudder stock on Megawat was corroded and the copper based anti-fouling may have played a part in that corrosion although this was not apparently the reason for the failure. The owners were apparently unaware of the aluminium stock's potential for corrosion due to the copper based anti-fouling.
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DickB
regular
Reged: 20/12/2002
Posts: 495
Loc: Surrey, UK
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Well it is definitely fibre glass (or maybe carbon fibre in there as well. I think the idea of using a rubber gasket material is a good one, and we may try that. Not really very impressive bit of technology!!!
thanks for your help
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Dick
Less work, more sailing...
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