Leaking rudder tube -what's the likely setup?

robmcg

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We have a long keeled boat with a rudder that is attached to the bottom of the keel by a lower bracket. The rudder stock is bronze and extends into the boat inside a stainless steel tube that is supported by a cross member glassed onto the sides of the hull. The stainless steel tube ends above the waterline. We have a leak, with water dripping out of the top of the stainless tube and dripping down into the bilge. The drip is more pronounced when the rudder is in use. I presume there is some sort of nylon bush between the bronze rudder stock and the stainless steel rudder tube. Is this likely to be the only thing in there or is there likely to be an intermediate bearing in there as well. Working on the principle of it ain't going to get better, we will attend to the issue over winter but where is someone likely to source the nylon bush/bearing that sits between the bronze rudder stock and rudder tube?

Rob
 

Tranona

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Hopefully it won't be nylon. More likely to be either Tufnol or an acetal such as Delrin. You really have to dismantle it to find out how it is installed. Once you find out its size and how it is secured into the tube, not difficult to get a new one machined. You may find, though that it has some form of seal that has worn and allowing water to come up. There is probably also a bearing at the bottom end of the tube where it comes through the hull, and that is also likely to be a water lubricated material such as Delrin.
 

Steve_N

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Ours has a similar arrangement to a propellor shaft stuffing box on top of the rudder tube and the seal is provided by packing material just as in a propshaft.
Is there nothing similar on the inboard/top end of your rudder tube to keep the water out?
 

robmcg

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Ours has a similar arrangement to a propellor shaft stuffing box on top of the rudder tube and the seal is provided by packing material just as in a propshaft.
Is there nothing similar on the inboard/top end of your rudder tube to keep the water out?

This is what I would have expected to see but there is nothing on the top end of the rudder tube, which does surprise me.
 

knuterikt

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We have a long keeled boat with a rudder that is attached to the bottom of the keel by a lower bracket. The rudder stock is bronze and extends into the boat inside a stainless steel tube that is supported by a cross member glassed onto the sides of the hull. The stainless steel tube ends above the waterline. We have a leak, with water dripping out of the top of the stainless tube and dripping down into the bilge. The drip is more pronounced when the rudder is in use. I presume there is some sort of nylon bush between the bronze rudder stock and the stainless steel rudder tube. Is this likely to be the only thing in there or is there likely to be an intermediate bearing in there as well. Working on the principle of it ain't going to get better, we will attend to the issue over winter but where is someone likely to source the nylon bush/bearing that sits between the bronze rudder stock and rudder tube?

Rob
Assuming the bearings are OK and the only problem is leaking you could consider to use a gaiter.
According to Jefa you can install this if the rudder tube is at least 100 mm above the waterline and a clearance between the top of the tube and the rudder quadrant.

Picture of mine
th_IMG_1632_zpsb378c0ba.jpg


You can read more here http://jefa.com/products/products.htm
 

Seajet

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As the boat bobs up and down in the water, the water in the tube is forced out of the top, presumably by the pressure of the water coming up the tube from underneath.

Could it be there was an end cap on the bottom of the tube which has fallen off - have you seen the bottom of the rudder tube before to know if this might be the case ?
 

robmcg

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Assuming the bearings are OK and the only problem is leaking you could consider to use a gaiter.
According to Jefa you can install this if the rudder tube is at least 100 mm above the waterline and a clearance between the top of the tube and the rudder quadrant.

Picture of mine
th_IMG_1632_zpsb378c0ba.jpg


You can read more here http://jefa.com/products/products.htm

That could be the ticket! I see you can get a retrofit kit that means you don't have to drop the rudder. Seems like a decent solution as there seems like there is no other way of sealing the rudder tube other than by the lower bearing which showed no external sign of damage or play at survey or prior to launch. The leak is more annoying than anything else as we end up with a few teaspoons of water behind the gearbox every few weeks.
 

NUTMEG

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My mk1 Cornish crabber is similar. Stainless shaft inside a GRP tube. No bearings, seals or means of lubrication. Water can slosh up the tube in a chop. British engineering at its very best:)

I toyed with the idea of adding a grease nipple but thought its lasted thirty odd years so will probably see me out!
 

Neil_Y

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where is someone likely to source the nylon bush/bearing that sits between the bronze rudder stock and rudder tube?

Rob
A supplier of rudder bearings. The latest composites can be used to replace water ol or greased bearings and some can also be made thin enough to replace white metal bearings if this is what you have. Have you checked to see how much movement you have at the top? If the top of the tube is that close to water level you want a good seal/packing system/gland, if the bearings wear then the packing becomes less effective at keeping water out (if this is the set up) Many times you won't know the set up until you take it apart. A recent job we did had packing which will be replaced with O rings, as the packing had caused crevice corrosion in the stainless steel parts. Crevice corrosion occurs where there is trapped sea water next to SS this is quite often the case in upper rudder bearings.
 

winsbury

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Assuming the bearings are OK and the only problem is leaking you could consider to use a gaiter.
According to Jefa you can install this if the rudder tube is at least 100 mm above the waterline and a clearance between the top of the tube and the rudder quadrant.

Picture of mine
th_IMG_1632_zpsb378c0ba.jpg


You can read more here http://jefa.com/products/products.htm
Exactly what I need too... we seem to take on lots of water in lumpy seas via the rudder tube...thanks for the link
 
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